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Thermal Performance of Floor Screed: How it Contributes to Energy Efficiency

Polycote Easi-Screed Flexible has proven to be the No. 1 choice for property owners, architects, and construction companies alike, due to its high thermal conductivity from the underfloor heating pipes, which has been shown to be around five times more effective than traditional screeds.

Professionally formulated with self-compacting properties, the liquid screed completely covers the underfloor heating pipework, eliminating air voids to ensure optimal heat transfer. It can be installed at much thinner depths compared to traditional sand and cement, providing ultimate control of the underfloor heating system. Energy usage and costs are greatly decreased when over-screeded with Easi-Screed Flexible, due to the system’s increased efficiency.

Easi-Screed Flexible has incredibly high strength and durability (with a compressive strength of 35N/mm²) together with low shrink characteristics. This allows the screed to be installed at far less thickness than traditional screeds, requiring a minimum of only 20mm cover to underfloor heating pipework. This therefore ensures far better heating performance, and faster heat transfer.  It is perfect for use with ground source and air source heat pumps, allowing lower flow temperatures, reduced energy consumption, CO2 emissions, and heating costs, as well as quick heating and cooling for greater system control.

The thermal conductivity of typical building materials can be measured according to standards such as BS EN 12664, BS EN 12667, and BS EN 12939. In comparison to electric-based systems, hydronic systems containing water and antifreeze offer both heating and cooling operations. Being a highly conductive thermally, this self-compacting anhydrite screed provides improvements over conventional screed or slab construction systems by reducing reaction time and enhancing thermal energy transfer.

Depending upon the method of construction, the thermal conductivity of the Easi-Screed system has been measured at between 2.2W/mK, and 2.9W/mK, therefore making it extremely responsive to underfloor heating. The lower thickness of the screed and high thermal conductivity, contribute to improved performance and substantially reduced response time for the entire system.

Easi-Screed Flexible has also been professionally formulated to be compatible for use with almost any underfloor heating system, including both conventional and renewable technologies. The strength, durability, and low shrink characteristics of the screed enables reduced depths without compromising performance and is suitable for most modern construction methods and substrates, subject to suitable engineering. The flowing and self-compacting nature of Easi-Screed Flexible, combined with its unique minimum depth capabilities, have enabled significant gains in placement time. Our contractors are now able to install up to an incredible 2000m² in just one working day. Compared with the limitations of traditional sand cement screeds, this is a massive saving in labour costs and downtime.

Furthermore, whilst on the subject of cost savings and speed, Polycote Easi-Screed allows for faster installation of final floor coverings as opposed to calcium sulfate screeds, which require a final moisture content of 0.5%, potentially delaying floor finishing by months. Easi-Screed can be tiled at a final moisture content of 5% and timber floors can be installed at a final moisture content of 2.8%, thereby expediting the entire build process with far less installation and curing times.

The complete range of Polycote Easi-Screed products are suitable for almost any type of floor covering, from tiles, terrazzo, wood, epoxy and polyurethane coatings and screeds, carpets, and vinyl flooring…, to name but a few!

Finally, Polycote Easi-Screed offers huge environmental benefits, by using far less of earth’s natural resources due to thinner application depths over against those required by conventional screeds. A win-win solution.

Related articles

What is a floor screed?

Types of floor screed.

Polycote UK would like to take the opportunity to thank you for taking an interest in these product and application articles and hope they have been some help to you.

We would of course be pleased to answer any specific questions should you wish to contact us directly on 01234 846400 or email: [email protected]


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Self Levelling Liquid Screeds -V- Traditional Sand / Cement Screed

Traditional screeds made by mixing sand and sharp sand by hand or cement mixer are rapidly becoming a ‘thing’ of the past.  They are perfect for new construction where time is not of the essence and where budgets are tight.  However, as soon as downtime becomes an issue, traditional screeds are simply no longer the answer.  Agreed, the liquid screed material is considerably more expensive than its traditional sand/cement ‘cousin’, but as soon as downtime is considered, the extra material cost pales into insignificance.

Easi-Screed is manufactured in various formulations to cover virtually all eventualities.  With fast curing formulations for areas of restricted downtime, a flexible formulation for the successful covering of underfloor heating, together with an external grade self-levelling version with the ability to withstand the extremes of weathering the Polycote Easi-Screed system has become synonymous with fast and easy!

Why choose a liquid screed instead of a traditional sand and cement screed?


The Polycote Easi-Screed system is now widely recognised as one of the best alternatives to traditional sand and cement screeds. Being able to lay up to 2000m² in a single day together with its speed of cure allowing pedestrian traffic after only 4 hours and vehicular traffic after on 24 hours, makes Easi-Screed one of the fastest and easiest self-levelling cementitious screeds of all time.


When using traditional concrete or sand/cement screeds, there is an industry standard code, normally between M10 and M55, denoting the average compressive strength for each code, as shown below.

Traditional Concrete Codes Compressive Strengths (N/mm2) Usage
M10 10 N/mm² Foundations, Light domestic.
M15 15 N/mm² Foundations, Light domestic.
M20 20 N/mm² Foundations, Light domestic.
M25 25 N/mm² Foundations, Light domestic.
M30 30 N/mm² Domestic / light industrial flooring
M35 35 N/mm² Domestic / light industrial flooring
M40 40 N/mm² Heavy duty industrial flooring installations
M45 45 N/mm² Heavy duty industrial flooring installations
M50 50 N/mm² Heavy duty industrial flooring installations
M55 55 N/mm² Heavy duty industrial flooring installations

The generally recognised period of time for traditional sand/cement screeds

to achieve the above-mentioned compressive strengths is approximately

1 month, per inch thickness of screed laid. This of course would also be

dependent upon the level of humidity and the average temperature range.

Polycote Easi-Screed is available if four different versions, and their respective strengths/curing times. You will note they all reach high strengths far quicker the traditional screeds, thereby ensuring a far quicker return to work.

Product Name Easi-Screed Industrial Easi-Screed Standard Easi-Screed Flexible Easi-Screed External
Applied By Trowel or Pump Trowel or Pump Trowel or Pump Trowel or Pump
Compressive Strength 40N/mm² 36N/mm² 34N/mm² 36N/mm²
Pot Life @ 20°C 25 mins @ 20°C 20 – 30 mins @ 20°C 20 – 30 mins @ 20°C 15 mins @ 20°C
App. Temperature 10°C – 20°C 5°C – 25°C 5°C – 25°C 5°C – 20°C
App. Thickness 5 – 50mm per layer 2-20mm per layer 2 – 50mm per layer 5 – 15mm per layer
Initial Cure @ 20°C 2-3 hours 2 – 3 hours 2 – 3 hours 6 hours
Overcoat Time 24 hours 24 hours 24 hours 24-48 hours

Minimum Thickness

There are in fact several reasons why a liquid pumped screed is far quicker and ultimately less expensive.  In addition to the speed of installation, traditional screeds require a minimum thickness far exceeding that of a liquid screed.  An absolute minimum of 50mm is recommended for a traditional screed and this often increases to 100mm or even 150mm, depending upon the thickness/state of the existing floor, as well as the amount of weight/traffic the new screed has to withstand.  Polycote Easi-Screed can be laid as thin as 2mm and for even the most heavily used areas, Easi-Screed Industrial can be laid at only 7mm.  Not only does this mean far less material required but also means that the existing floor height barely changes, which in turn has little effect on door or ceiling heights.

Furthermore, if only parts of a total floor area require a new surface, a raise in the floor area is, in 99% of cases, completely impractical. Conversely, Easi-Screed will produce a new surface with the transition for the original levels to the ‘new’ level being almost imperceptible.

Dust & Wearability 

Traditional screeds will nearly always result in the dissipation of dust, caused by the fine particles within the screed delaminating.  As these particles delaminate, the loose material almost acts as a grinding layer that exponentially exacerbates the problem.  All Polycote Easi-Screeds are non-dusting and therefore eliminate the huge ongoing issues caused by dust, whether it be general cleaning to damage to stock, machinery, and air conditioning systems.  As far as wearability is concerned, liquid screeds far exceed traditional screeds as they are far more resistant to heavy wear and tear.


Easi-Screed Flexible has been formulated to withstand pressures due to movement, vibration or where underfloor heating is used. The fibre reinforced, protein free design is highly flexible, yet still cures to 34N/mm².


The smoothness of the final finish of a liquid screed far exceeds that of a traditional screed.  This means that the final floor finishes such a carpet, tiles, wood flooring, etc are far easier to lay and in turn ensure a far better overall finish. And talking of the over-laying of the screed with tiles, carpeting, etc, the curing period of a traditional screed often requires an absolute minimum of 3 days before any such over-laying can be achieved.  When considering paint and depending upon the age of the advisor’ the standard advice give is ‘one month per inch’ (thickness of screed) or ‘1mm per day’.  With any of our Easi-Screed liquid screeds, these can be painted, tiled, covered after only 24 hours!

In summary

The benefits of a liquid screed system such as Polycote Easi-Screed are as follows:

  • Speed of installation – up to 2000m² in one day
  • For small to medium sized floors up to 3-400m², Easi-Screed can be quickly and easily mixed on site using a mixing paddle fitted to a standard hand drill. For larger industrial applications, the material can be mixed in much larger quantities and then pumped onto the floor via a large hose.
  • Can be laid as thin as 2mm.
  • Non-dusting
  • Smoother and more level surface. Indeed, Easi-Screed can be laid to a laser-level finish.
  • Cures and ready for trafficking after only 4 hours (pedestrian) or 24 hours (vehicular)
  • Cures and ready for over-laying of final floor finishes after only 24 hours.
  • Much quicker and easier to clean, thereby reducing cleaning times and costs.
  • Almost Imperceptible raising of existing floor heights.
  • Reduces the need for removing existing floor slabs thereby reducing waste disposal costs
  • Reduces noise, dust and inconvenience as well as

Related articles

Checklist For Self Levelling Floor Screed

Types of floor screed.

Thank You

Polycote UK would like to take the opportunity to thank you for taking an interest in these product and application articles and hope they have been some help to you.

We would of course be pleased to answer any specific questions should you wish to contact us directly on 01234 846400 or email: [email protected]








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Screeding A Floor During Periods Of Low Temperatures Or Wet Weather

When installing floor screeds in poor weather, damp conditions and/or during periods of low temperatures, it is important that adequate precautions and protection measures are taken to ensure a successful installation of a new screed.

First and foremost, we advise that you read and fully understand the manufacturers data sheet that should clearly show the recommended application temperatures.

Cold Weather / Low Temperatures

As a general rule, the colder the temperature, the longer the curing time will be.  However, if the temperature drops too low, then this will affect the curing time so much that it could lead to a poor or even non-cure situation.  Indeed, if the uncured material is affected by frost / freezing conditions, the screed will not cure and will have to be removed and new material re-laid.

If the area to be laid is in an unheated warehouse, or maybe in what is an unused/empty building, the area should be heated up with space heaters or similar to a suitable temperature, somewhere between 10°C and 20°C.  Remember, if you are using space heaters, hot air rises and whilst it may indeed seem warn, the floor itself can take a lot longer for its temperature to rise, so it is well worth turning the heat on in the area well in advance of the day of installation, in order for the fabric (and specifically the floor) to ‘warm up’.  Don’t forget, the temperature of a concrete floor is hugely influenced by the ground temperature externally.

Once the floor is laid, ensure the building stays at the minimum temperature for the duration of the curing process.

Other specific areas of concern are where the external perimeter of the floor meets with an external wall.  Again, such areas can remain at a lower temperature due to cold penetration from outside.

Finally, doorways are another area that need to be considered, particularly industrial doors.  Cold draughts able to penetrate under such doors can also seriously affect the curing process.  Some people choose to sandbag or simply tape up along the bottom of the doors to help prevent such draughts.  Other considerations are if the doors cannot be fully closed due to the screed passing directly below.  In such circumstances, some people will lay cloths or some form of insulation material along the outside of the doors to help fill the gap and thus prevent unwanted draughts.

Wet Weather

It is vitally important that the newly laid uncured screed is not allowed to get wet before it has fully cured.  Equally, the underlying substrate must not be too wet in order to be able to lay a screed on top.  Such areas are best allowed to dry prior to the application of a screed.  Again, refer to manufacturers data sheets and guidelines on such matters and if still in doubt, ring the manufacturer and speak to a qualified person.

Similarly, to what has already be touched on in the Cold Weather Low Temperature section above, take note of the seal under doorways and ensure they are watertight.  Again, sandbag, tape or cover any such gaps with some form of waterproof material as damp/water penetrating onto an uncured screed with cause a poor or non-cure situation.

Roof leaks should obviously be repaired and sealed prior to the laying of any new screed in case of unwanted rain, as should any machinery or pipework leaks.

What can affect curing times?

The curing period of a new screed is hugely dependent upon the atmospheric temperature together with the existing floor substrate temperature.  The colder the temperature, the longer the material will take to cure.

Equally, the humidity levels can hugely affect the ultimate curing and hardness of the new screed.  Remember, water is added to the screed and this needs to be able to evaporate during the curing process.  If the weather is inclement and/or the air is saturated with water due (mainly) to recent rainfall and low temperatures, the water within the new screed will be unable to dissipate into the already ‘waterlogged’ atmosphere and thus, this can greatly extend the curing process.

Good airflow through a building is always a good way of helping to dissipate evaporating water as a very hot, airtight area can have an equal effect of the room sweating and thus preventing the water from escaping from the screed.

Transportation and Storage

Water will affect the properties of both cement and aggregates. Therefore, it is vitally important that all materials are stored in dry locations and protected from moisture and rainwater.

It is worth noting that screeds, particularly self-levelling floor screeds have been formulated to have a specific amount of water to be added to allow both the product to be able to be laid, to be able to initially cure and to be able to harden to the strengths as proven in prior testing.  If materials are allowed to take in water or dampness prior to the mixing process, this will affect all of the above-mentioned points, where it be the pourability of the and curing of the material.  Finally, and as a result of too much water within the mix, this then impacts the ultimate strength/hardness of the cured material which will reduce the usability / longevity of the finished floor surface.  All for the sake of not taking a bit of care!

But we’d like to finish on a good note so our final advice is; look after the materials and they will look after you!

Related articles

Checklist For Self Levelling Floor Screed

Types of floor screed.

Polycote UK would like to take the opportunity to thank you for taking an interest in these product and application articles and hope they have been some help to you.

We would of course be pleased to answer any specific questions should you wish to contact us directly on 01234 846400 or email: [email protected]

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Checklist for Self-Levelling Floor Screeds

Pourable Flexible Screed

Choosing the right floor screed system might seem complex but with a little help and guidance afforded from this simple checklist, we feel you will be well on the way to making some better and more informed decisions to assist with your project.

Of course, we would welcome you to contact one of our team, who will happily establish exactly what your circumstances and requirements are and be able to answer any of your questions or concerns. We will be able to tell you exactly what product to use and the reason and justification for the said product.

However, for your initial perusal we hope you find the following information useful.

  1. Screed Specification

There are a huge variety screeds now available, so the most important check is to make sure the screed in question is suitable for your requirements:

  1. Strength (Normally shown as N/mm)
  2. Minimum thickness
  3. Maximum thickness
  4. Pot life
  5. Curing times
  6. Minimum application temperatures
  7. Maximum application temperatures
  8. Flexural strength (where relevant)

Further helpful advice can be found in the British Standards information documents; BS8204 and BS800

  1. Inspection of Existing Floor Structure

It is vitally important to inspect the exiting screed thoroughly prior to the application of any screed.  Please note: the suggested remedy for each point will be outlined later in this document.

  1. Check the condition and soundness of the existing surface.
  2. Check for any evidence of structural cracks.
  3. Check thoroughly for any evidence of damp.
  4. Check thoroughly for any evidence of oil contamination.
  5. Check the levels of the floor to ascertain the high and low points.
  6. Check for existing expansion joints and mark their exact locations prior to the layman of any screed.
  7. Establish whether any part of the floor has underfloor heating.
  8. Is the floor area to be screeded internal (within an enclosed building) or external (open to the elements)?
  1. Base Preparation

Condition and soundness of the existing surface

The existing surface should be thoroughly cleaned and ‘keyed’ to ensure a perfect adhesion between the new screed material and the existing concrete slab.  It is vitally important to remove all loose/friable material including any existing floor paint or sealer.

Preparation can be carried out chemically with the use of an acid etching material (Polycote Etch It), or mechanically with the use of diamond floor grinders, scabblers and/or shot blasters.  It is highly advised that you use a machine connected to a dust recovery unit / industrial vacuum to ensure the entire area is not filled with dust.

Structural cracks

If your floor is suffering from structural cracking, it is highly advisable to establish why the cracking of the concrete has occurred. This could be for several reasons, a) the most common reason being not enough or indeed no expansion joints, b) expansion joints that are no longer functional due to the build-up of dirt within the joint c) the joint has been incorrectly filled in with an inert, solid (repair) material thereby preventing the screed from being able to expand or contract, d) the screed being subjected to too much weight or c) subjected to too much vibration, often caused by heavy machinery.

Obviously, there is little the user can do about the weight or movement of machinery but, if it is simply an issue with the expansion joints, this can be easily rectified by cleaning/re-cutting the joint and filling with a Polycote Jointex expansion product specifically formulated to allow for expansion and contraction.

With regard to any structural cracks, it is advised to both clean and dry out the crack as much as possible and fill with Polycote Crackfiller EP100, an ultra-low viscosity pure epoxy resin.

Rising Damp

If any rising damp has been identified, the floor must be coated with a twin pack epoxy Damp Proof Membrane (Polycote DPM Primer), to provide a totally waterproof barrier and thus prevent the rising damp from pushing up through the new floor screed.

Oil Contamination

If oil contamination has been identified, it is important that all surface contamination is removed as much as possible using Polycote Degrease IT.  Once the surface is clean, paint the floor with Polycote OT Primer in order to totally seal the surface and prevent the oil from rising up through the new screed.

 Further Note:  Re. Damp and Oil

When applying either the OT Primer or the DPM Primer prior to the installation of a screed, it is recommended that two coats are applied.  The first coat should be applied and allowed to cure, prior to a second coat being applied at right angled to the first.  Whilst the second coat is still wet, kiln dried quartz aggregate should be sprinkled on to the wet primer.  All excess aggregate may be removed the following day and prior to the installation of the self-levelling floor screed (Polycote Easi-Screed).

High and Low Points – What is best to do?

This is often an interesting consideration as to what is best to do. If you have a poorly laid concrete with a ‘few’ high spots that are causing an issue, it is worth contemplating whether just to grind the high spots down and not put a screed at all.  However, please bear in mind that for every 1sq.m x 1mm deep, you will be removing approximately 2kgs of concrete.  Whilst this might not sound much, now multiply the total area you have with the depth you wish to remove and multiply that by 2.  You will then know how many kilos you are going to have to move, and the skip(s) you will need to take the waste!

When allowing for the minimum thickness required for the chosen screed, make sure you allow this depth over the high spots and will then need to calculate how much material you will need in excess to fill in the lower areas, which in turn, will obviously be laid to a greater thickness.

If you are not sure how to calculate this, then please don’t hesitate to call the technical helpline 01234 846400, where one of the team will be more than happy to offer help and advice.

  1. Expansion Joints

Expansion joints are a vital part of a successful and long-lasting concrete floor.  It is therefore important that you mark out on a plan exactly where they are so that the joints can then be reinstated by cutting through the new screed once it has cured.

Alternatively, rather than going by a written plan, a mark can be made on the wall denoting the starting/finishing points. Alternatively, some people simply use 6” nails that are driven into the joint.  This method is actually very helpful, especially when you have existing slabs where the joints are not in a nice straight line, or the joints are ‘dog-legged’ or simply not at 90°.  This way, the whole length of joint can be easily plotted and then as soon as the screed has cured sufficiently to walk on, the nails can be pulled out and will then clearly leave holes that will show the exact path of the original expansion joint below.

Please note it is very important the cutting through of the joints is done directly over the existing joint below.

Once cut, the open joint should then be filled with one of our Jointex range of products, to both protect the edges of the joint and to prevent the build-up of dirt in the joint.

  1. Underfloor Heating

When screeding over an underfloor heating system, no matter whether it is a wet system or electric, you should use Easi-Screed Flexible. This has been formulated to reduce the risk of cracking due the extra expansion and contraction brought on by the greater fluctuations of direct heat.

  1. Internal / External Applications

Easi-Screed Industrial, Easi-Screed Standard and Easi-Screed Flexible are all suitable for use internally, within a building.  However, if you have an external application, where the product will be subjected to the extremes of weathering, please us Easi-Screed External.

  1. Mixing

Due to there being many and varied self-levelling compounds we can only advise that you read and fully understand the Manufacturers Material Data Sheet, prior to the mixing and/or application of any product.  Should you have any questions or concerns, contact the manufacturer before any commencement of works.

It is important that you have the entire area prepared and primed as necessary.  Fill a suitable clean mixing vessel with the required quantity of clean water as per the material data sheet.  Add the contents of the Easi-Screed (powder/aggregate) to the water whilst mixing and folding in with the mixing paddle.  It is highly advised to use a mixing paddle connected to a suitable drill as it is important that the product is mixed evenly, thoroughly, and as quickly as possible.

  1. Pouring and Levelling

Pour the mixed material out onto the floor and spread out with a pin leveller. The length of the pins on the Pin Leveller should be set to the thickness of screed required. As soon as the screed has been spread out, the floor should be ‘spiked’ with the spiked roller to pop/disperse any air that has become entrapped in the screed whilst mixing.  Please note, it is both normal and inevitable that air bubbles become entrapped in the mixture, and it is therefore very important that the screed is spiked as soon as possible after laying, whilst it is still wet. This will also help the screed itself to level out and also help each poured mix to merge perfectly with its previously laid counterpart.

Please note:  It is extremely important to maintain a wet edge so that each pour blends in perfectly with the previous pour.

Spiked shoes are also available for the user to enable them to be able to walk over the wet screed during the pouring procedure.

  1. Curing

The benefit of installing one of the Easi-Screed range of self-levelling screed system is speed.  Its fast to mix, fast to lay and fast to cure. So much so, that one of our teams of approved installers can lay up to 2000sq.m in just one day, which can then be traversed by vehicular traffic the very next day! Furthermore, Easi-Screed provides a high wear, smooth and dust free surface and can be laid as thin as 2mm.

  1. Screed Protection

Ensure the new screed is protected during the curing process.  The temperature should not be allowed to drop below 10°C, space heaters are advised in the colder months.  Protect from foot traffic for a minimum of 3 hours and from pallet trucks and forklifts for 24 hours. Consult the manufacturer’s Material Data Sheet for specific requirements or ring our technical helpline for further advice.

  1. Sealing the Surface

If the floor is likely to be subjected to liquids or if you would like to paint it for aesthetic reasons, it is highly advised to complete this exercise as soon as possible after laying and before any ‘major’ use.  It is far better to complete a coating before the screed has been able to absorb impurities into itself, whether it be oil or chemical spillages, from general dirt to rubber tyre marks.

For a clear sealer, Polycote Flortex PU is an excellent single pack polyurethane floor sealer.

Should you wish to achieve a colour, 2 coats of a twin pack water dispersed epoxy resin (Polycote Flortex SG) is one that can be applied after just 24 hours.

Finally, if you are looking for the best, then one coat of Polycote WD Primer followed by one coat of Polycote Flortex Professional, will give you the longest lasting high build coating, that is resistant to both chemical and heavy traffic.

Related articles

What is a floor screed?

Types of floor screed.

Polycote UK would like to take the opportunity to thank you for taking an interest in these product and application articles and hope they have been some help to you.

We would of course be pleased to answer any specific questions should you wish to contact us directly on 01234 846400 or email: [email protected]



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6 Most Common Causes for Concrete Cracks

Concrete is a widely used building material due to its strength and durability. However, it is not immune to cracks. Understanding the causes of concrete cracks is crucial to prevent structural issues and ensure the longevity of buildings and infrastructure. In this article, we will explore the six common causes for concrete cracks and discuss preventive measures to mitigate them.

Understanding the Nature of Concrete

Before considering the causes of concrete cracks, it is essential to grasp the composition and characteristics of concrete and the understanding of the composition and properties of concrete is crucial in ensuring its long-term durability and structural integrity.

Having been used for centuries as a reliable and versatile construction material, the mixture of cement, water and aggregate gains strength over time through a process called hydration, where the cement particles react with water to form a solid mass. Its ability to withstand heavy loads and resist weathering makes it a popular choice for various applications, from building foundations to road pavements.

The Composition of Concrete

The composition of concrete plays a significant role in its strength and integrity. The proportion of cement to water affects the hydration process. Insufficient water can lead to inadequate hydration, resulting in weaker concrete prone to cracking. On the other hand, excessive water can cause shrinkage and reduce durability.

In addition to cement and water, aggregates such as sand and gravel are added to the concrete mixture. These aggregates provide bulk to the concrete and contribute to its overall strength. The size and shape of the aggregates can also affect the workability of the concrete, making it easier or more difficult to place and compact.

Furthermore, chemical additives and fibres can be incorporated into the concrete mix to enhance specific properties such as:

1) Plasticizers: formulated to improve workability, making the concrete more fluid and easier to pour.

2) Air-entraining agents; to create tiny air bubbles in the concrete, which increases the concretes resistance to freeze-thaw cycles.

3) Frost inhibitors: help support the curing of the concrete where conditions are colder than the required limits for ‘standard’ concrete mixes. extra fast curing agents. These can be added to a concrete mix where time constraints require a faster back-to-work time.

4) When added to the concrete mix, specialist fibres can provide added strength to the concrete as well as improving resistance to cracking.

The Durability and Strength of Concrete

Concrete’s durability and strength are influenced by factors such as the quality of the materials used, the curing process, and the mix design. Poor-quality materials or improper mixing procedures can compromise the structural integrity of concrete, making it susceptible to cracks.

During the curing process, the concrete needs to be protected from excessive moisture loss. This can be achieved by covering the concrete with plastic sheets or applying a curing compound. Proper curing allows the concrete to develop its full strength and reduces the likelihood of cracking.

Moreover, the mix design of concrete is crucial in determining its strength and durability. The ratio of cement to aggregates, as well as the type and proportion of additives, can significantly impact the performance of the concrete. Engineers carefully design concrete mixes to meet specific project requirements, considering factors such as load-bearing capacity, exposure conditions, and desired lifespan.

It is also worth noting that the curing time of concrete plays a role in its ultimate strength. While concrete gains strength rapidly in the first few days, it continues to harden and develop strength over an extended period. This is why construction projects often specify a minimum curing time before subjecting the concrete to heavy loads or other stressors.

In conclusion, understanding the composition and characteristics of concrete is essential in ensuring its long-term durability and structural integrity. The proportion of cement to water, the quality of materials, the curing process, and the mix design all contribute to the strength and performance of concrete. By paying attention to these factors, engineers and builders can create concrete structures that stand the test of time.

The Impact of Environmental Factors on Concrete

Concrete is a widely used construction material due to its strength and durability. However, it is not impervious to the effects of the environment. Environmental factors play a significant role in the deterioration of concrete, affecting its longevity and structural integrity. Two of the most common culprits behind concrete cracking are temperature fluctuations and moisture.

Temperature Fluctuations and Concrete Cracks

Concrete is known to expand when exposed to high temperatures and contract under freezing conditions. These temperature fluctuations can create significant stresses within the concrete, leading to cracks over time. Imagine a scorching summer day, with the sun beating down on a concrete structure. As the temperature rises, the concrete expands, trying to accommodate the increased thermal energy. However, when the temperature drops during the cool night, the concrete contracts. These repeated cycles of expansion and contraction can weaken the concrete’s structural integrity, making it more prone to cracking.

In addition to the regular expansion and contraction, rapid temperature changes can cause a phenomenon known as thermal shock. Imagine a sudden downpour after a scorching day. The rainwater, being cooler than the concrete, causes rapid cooling. This sudden temperature change can create stress within the concrete, leading to cracks. Thermal shock can also occur during winter, when concrete structures are exposed to freezing temperatures after being heated by the sun during the day.

The Role of Moisture in Concrete Deterioration

Moisture is another critical environmental factor that affects concrete. When water enters the concrete, it can react with the cement, leading to expansion and subsequent cracking. This process is known as the alkali-silica reaction, where the alkalis in the cement react with the silica present in the aggregates, forming a gel-like substance. As this gel expands, it exerts pressure on the surrounding concrete, causing cracks to develop.

Moreover, moisture can corrode the reinforcing steel within the concrete. Reinforced concrete relies on steel bars or mesh to provide additional strength. When moisture penetrates the concrete and reaches the steel, it can initiate a process called corrosion. Corrosion weakens the steel, compromising its ability to provide reinforcement and support to the concrete. This not only affects the structural integrity of the concrete but also reduces its load-bearing capacity.

Furthermore, moisture can also lead to the growth of Mold and mildew on the concrete surface. These organic growths not only make the concrete aesthetically unappealing but can also contribute to its deterioration. The presence of Mold and mildew can accelerate the breakdown of the concrete’s surface, making it more susceptible to cracking and erosion.

Considering the significant impact of temperature fluctuations and moisture on concrete, it is crucial to take preventive measures during the construction phase. Properly designed concrete mixtures, incorporating materials that can mitigate the effects of temperature changes and moisture, can significantly enhance the durability and longevity of concrete structures. Additionally, regular maintenance and inspection can help identify early signs of deterioration, allowing for timely repairs and preservation of the concrete’s integrity.

The Influence of Poor Construction Practices

Inadequate construction practices can have a detrimental effect on the quality of concrete. Two common factors contributing to cracks are inadequate concrete mixing procedures and improper curing.

Inadequate Concrete Mixing Procedures

Improper mixing of concrete ingredients can result in weak spots within the structure, making it susceptible to cracks. Insufficient mixing or uneven distribution of aggregate and cement can lead to a lack of homogeneity, compromising the overall strength of the concrete.

The Consequences of Improper Curing

Curing is a crucial step in the concrete curing process that ensures optimal hydration and strength development. When concrete is not properly cured, it can dry too quickly, leading to shrinkage and cracking. Insufficient curing time or exposure to adverse weather conditions can also hinder the curing process.

Lack of expansion joints

A concrete expansion joint is a gap which allows the concrete to expand and contract as the temperature increases or decreases respective, thereby allowing movement of the floor and reducing the stresses which are the major cause of cracking.

Concrete expansion joints are particularly important where separate pours of concrete are required. An expansion gap should always be provided as these ‘separate’ slabs will always be subjected to differing movement and vibrations caused by caused by traffic and/or machinery. Furthermore, an expansion joint (gap) should also be created between the floor and wall transitions as well as where there are differing materials (ie. metal inspection covers) where each material type has their own expansion and contraction characteristics.

It is always advisable to consult a structural engineer who will ensure the floor or structure has a sufficient quantity and size or expansion joint. However, for the purposes of this article here are some points for as a ‘general guide’ for your consideration:

1) Expansion joints should be incorporated into slabs with a surface area exceeding 6sq.m.

2) Expansion joints should be placed around 30 times the slab thickness apart.

Therefore, for a slab which is 100mm (0.1m) thick, the joints should ideally be placed around 3m apart.

3) When cutting expansion joints into previously poured and cured concrete, it is advised that the joints should be cut down to around a quarter of the thickness of the slab. So, for example, for a 100mm thick slab, the joints would be cut to approximately 25mm deep.  However, for thicker slabs (over 100mm thick), ensure that the cut joints are at least 25mm deep.

The Role of Excessive Load and Structural Stress

Concrete is designed to bear loads and provide structural support. However, excessive loads and structural stress can lead to cracks and compromise its strength.

Understanding Load-Bearing Capacity of Concrete

Each type of concrete has a specified load-bearing capacity. When this capacity is exceeded, cracks can occur. Determining the appropriate grade of concrete based on the expected load is crucial to ensure structural stability and prevent cracks.

How Structural Stress Leads to Cracks

Structural stress can arise from various factors, including improper design, settlement, and vibrations. When the applied stress exceeds the concrete’s ability to resist, cracks can develop. It is essential to consider all potential stressors during the design and construction phases to prevent future cracking.

The Effect of Shrinkage on Concrete Cracks

Concrete undergoes shrinkage as it dries and hardens. This natural process contributes to the formation of cracks if not adequately controlled.

The Science Behind Concrete Shrinkage

Shrinkage occurs due to the evaporation of excess water from the concrete. As the water evaporates, the volume of the concrete reduces, causing it to shrink. This shrinkage can result in cracking if not properly managed.

Preventing Shrinkage-Induced Cracks

To prevent shrinkage-induced cracks, various strategies can be employed. The use of shrinkage-compensating admixtures, joint spacing, and reinforcement techniques can help mitigate the negative effects of shrinkage and minimize cracking.

In conclusion, concrete cracks can arise from a combination of factors, including inadequate composition, environmental influences, construction practices, excessive loads, and shrinkage. Understanding these causes is essential in preventing structural issues and maintaining the durability of concrete structures. By adhering to proper construction techniques, considering environmental factors, and implementing preventive measures, we can ensure that concrete remains strong, durable, and crack-free for years to come.

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How to Repair a Concrete Floor

Polycote UK would like to take the opportunity to thank you for taking an interest in these product and application articles and hope they have been some help to you.

We would of course be pleased to answer any specific questions should you wish to contact us directly on 01234 846400 or email: [email protected]

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Painting, Sealing and Refurbishing Roof Tiles

Roof Tile Coat: roof paint to improve the appearance of your house

The roof of your home is more than just a protective shield against the weather. It’s a crowning statement of your home’s aesthetics, a testament to its charm and allure. But what happens when time leaves its imprint, dulling the colour of your roof tiles or even rendering them passe? If you’ve ever gazed up at your roof, contemplating whether a fresh coat of roof tile paint could rejuvenate its appeal, you’re not alone. The good news is that there are some excellent roof coatings that have been specifically formulated to not only adhere to roof tiles but more importantly, to withstand the expansion and contraction and extremes of weathering.

Understanding the Basics of Roof Tiles

What are Roof Tiles?

Roof tiles are individual units made from various materials such as clay, concrete, or metal. They are designed to cover the roof’s surface and provide weatherproofing.

Roof tiles have been used for centuries to protect buildings from the elements. In ancient times, people used materials such as straw, wood, or stone to create a barrier against rain, snow, and wind. As technology advanced, so did the materials used for roof tiles.

Today, roof tiles are manufactured using modern techniques and materials to ensure durability and longevity. They are designed to withstand extreme weather conditions, including high winds, heavy rain, and even hailstorms. This makes them an essential component of any well-built structure.

Clay tiles are the most traditional and offer a timeless look. Concrete tiles, on the other hand, are durable and cost-effective. Metal roof tiles are known for their longevity and energy efficiency.

Different Types of Roof Tiles

There are several types of roof tiles available in the market and there are coatings specifically formulated to refresh, refurbish and water-proof for each material type.

Clay roof tiles

Clay tiles have been used for centuries and are known for their timeless beauty. Made from natural clay, they have been shaped and fired in a kiln to create a durable and weather-resistant tile and are available in a range of colours and finishes, allowing homeowners to choose a style that complements their home’s architecture. Polycote Roof Tile Coat is the ideal for the refurbishment and weather-proofing of clay tiles.

Concrete roof tiles

Concrete tiles are a more modern option. They are made from a mixture of cement, sand, and water, which have been moulded and cured to create a strong and durable tile. Concrete tiles are available in a wide range of colours and styles, making them a versatile choice for any home.

As with Clay tiles, Polycote Roof Tile Coat offers maximum adhesion and weather resistance and will hugely prolong the life of concrete roof tiles

Metal roof tiles

Metal tiles are another popular option, especially for those looking for a long-lasting and energy-efficient solution. They are typically made from steel or aluminium and are coated with a protective layer to prevent rust and corrosion. Metal tiles are lightweight, easy to install, and can last for several decades with proper maintenance.

Polycote Polydex is a superb coating that not only has rust inhibitors built into the coating to prevent any further corrosion to steel materials but also has an incredible 200% elasticity, which enables the coating to easily withstand the extremes of expansion and contraction suffered by metal substrates.

Slate & Natural Stone roof tiles

Slate and natural stones tiles have been used for centuries and are known for their elegance and extreme durability and are often used on high-end homes and historic buildings, especially listed buildings that must comply with specific preservation orders.

Slate tiles can be coated with bituminous coatings such as Polycote Wetterflex or Poloflex Premier grade.  However, if your property does have and specific preservation order upon it, it is strongly advised that you speak with the relevant authority to discuss the possibility of coating the tiles.

Stone tiles can be sealed with several different coatings.  However, Polycote Stoneguard is regarded by professional stone roofers as one of the best.  It is totally unique, a completely clear liquid that soaks well into the stone itself, providing a waterproofing seal that is completely invisible to the eye! Thus, this material has never yet been refused by any historic or preservation authority.

Asphalt and Fiberglass roof tiles

These roof tiles are also available and mostly referred to a asphalt shingles and are made from a combination of asphalt and fibreblass, making them lightweight and easy to install. Asphalt shingles are available in a variety of colours and styles, making them a popular choice for homeowners.  Polycote Poloflex or Acraflex coatings are ideal for the coating and waterproofing of Asphalt and/or Fibreglass roof surfaces,

Advantages of Painting Roof Tiles

The main two advantages of painting roof tiles is speed and cost. To be able to effectively re-roof without the need of replacing the entire roof has massive benefits in the saving of huge costs as well as the problems of weather and security when having to remove/replace and entire roof covering.

Whether you want to change the colour or simply restore the original vibrancy, painting can transform the appearance of your roof. Imagine driving up to your house and being greeted by a beautifully painted roof that complements the overall aesthetic of your property. It can instantly enhance the curb appeal and make your home stand out in the neighbourhood.

Additionally, painting can provide an extra layer of protection against the elements. British weather can be unpredictable, with rain, wind, and even snow making their appearances throughout the year. By painting your roof tiles, you can create a barrier that shields them from the harsh effects of these elements. This added protection can help extend the lifespan of the tiles, saving you money in the long run by reducing the need for frequent repairs or replacements.

Step-by-Step Guide to Painting Roof Tiles

1)      Necessary Tools and Materials for Painting Roof Tiles

To paint your roof tiles, you’ll need a few specific tools and materials. These may include a pressure washer for cleaning, a stiff brush for removing debris, paint suitable for roof tiles such at Roof Tile Coat from Polycote UK, and a long-handled paint roller or sprayer for application. If you have any plant growth such as moss or lichen, use a plant/weed killer such as Polycote Destroy IT.

2)      Assessing the Condition of Your Roof Tiles

Take the time to inspect your roof tiles carefully. Firstly, replace any missing tiles. Look carefully over the whole area, checking for any cracks, damaged, or signs of wear and tear, especially any delamination caused by frost damage and either repair or replace as necessary.

3)      Cleaning the Roof Tiles

Cleaning the roof is the most vital step to ensuring the success of any subsequent coating.  The use of a pressure washer will normally make light work of removing dirt, moss, and other debris. For stubborn stains, a stiff brush can be used to scrub the specific areas.

If you have plant growth such as moss or lichen, remember that it is vitally important the vegetation is completely killed at the roots. So to this end, remove all the surface growth whilst cleaning with the pressure washer and allow roof to dry.  The wash of the affected areas with Polycote Destroy IT.  This chemical will then penetrate deep into the roots that have embedded themselves into the tiles and will kill the root.  If this is not done, the plant will continue to grow and will eventually push up and break through the coating.

4)      Applying the Primer

Before applying paint, it’s crucial to apply a suitable primer. The primer helps the paint adhere to the tiles and ensures an even finish. Choose a primer specifically designed for roof tiles and apply it according to the manufacturer’s instructions.

However, roof coatings such as Polycote Roof Tile Coat, does not require a primer as it has self-priming capabilities and simply requires two coats of the same product.

5)      Painting the Roof Tiles

When painting a roof it is important to ensure the chosen paint is specifically formulated for roof tiles and has the capability of withstanding the extreme weathering that all roofs are subjected to, whether it be prolonged periods of both hot and cold temperatures or the expansion and contraction issues caused by freeze/thaw cycles.

It is important to note many exterior paints are perfect for walls and vertical surfaces but are not equal to the extremes of flat or pitched areas.

Apply the paint with a long-handled paint roller or sprayer, starting from one end and working your way across the roof. Allow the paint to dry as per the manufacturer’s instructions and apply a second coat if necessary.

Further note: If applying by sprayer, take great care. Only a light wind can carry the sprayed material far away from the intended surface and end up on neighbouring property!!!

Maintaining Your Painted Roof Tiles

Proper maintenance is key to keeping your painted roof tiles looking their best for years to come. To keep your painted roof tiles clean and in good condition, it’s essential to perform regular maintenance. Remove any debris or leaves that may accumulate on the roof, as these can cause discolouration or damage. Inspect the tiles periodically for any signs of wear and tear and address any issues promptly.

Related articles

Worn and weathered roof that needed a refresh

Make sure you check your roof for snow damage

Polycote UK would like to take the opportunity to thank you for taking an interest in these product and application articles and hope they have been some help to you.

We would of course be pleased to answer any specific questions should you wish to contact us directly on 01234 846400 or email: [email protected]