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Sealing Masonry – Everything You Need To Know

Sealing masonry

Whether your home is of solid wall construction or has a cavity wall, the chances are it is vulnerable to water ingress. But what is water ingress & how does it impact the performance of your masonry walls? We have covered everything you need to know in this handy guide, so you can protect your masonry long-term.

What Is Masonry Sealing?

Masonry is a term that refers to exterior walled structures consisting of building materials bound together by mortar. Masonry is commonly made from brick, stone, concrete & limestone which all vary in terms of porosity & permeability. 

Porosity

You may be wondering, what do we mean by porosity? Well, in short, masonry substrates are not waterproof. Porosity refers to the amount of void space in a material, which is a key indicator of the materials ability to absorb & hold moisture. The more porous a masonry surface, the more water it can absorb. A conservative estimate for the amount of water a weathered brick (over 20 years old) could uptake is 20% its weight in water. This water makes its way through the pores of the material, hence the name porosity,

Permeability

Permeability refers to the the extent to which air or water can travel through a substrate. Where permeability comes in to the equation alongside porosity is in terms of 'breathability'. The breathability of a substrate, is a measure of how much water vapour can travel through a substrate. If a surface is not breathable, water vapour from inside the property will slowly build up as it has no escape outlet. Eventually, over time this will cause significant problems to a property that sometimes cannot be undone.

It is important to note that while similar, permeability and porosity are not the same. Porosity is a measure of how well a material holds moisture, while permeability refers to the ability to transfer water or air through the material. A substrate can be porous while being impermeable if the pores of the substrate do not allow the moisture to transfer right through the wall.

Brick sealer

While masonry surfaces as a natural substrate are designed to uptake moisture, with ageing masonry there is a danger that they will hold this moisture over time. When the temperature drops, this moisture can undergo a freeze-thaw cycle that results in the moisture within masonry expanding when it freezes. This movement causes cracks in the masonry to open up & expand, allowing more moisture to enter the building and continuing a cycle of deterioration.

As well as damage to masonry, water absorption can also lead to a variety of other side affects, including:

  • Heat loss - damp content of just 5% in a plain brick wall can lower the insulation by up to 50%. This is because wet walls transfer heat twice as quick as dry walls.
  • Damp problems - damp content in masonry walls can transfer into the internal wall of a property when the property is of solid wall construction or when it has poorly fitted cavity wall insulation. By filling a cavity wall with insulation, you can end up removing the space necessary for water to freely escape the building.
  • Discolouration - masonry that has been exposed to long-term water ingress can become discoloured by the moisture.
  • Green growth - moisture allows fungal growth such as moss & lichens to thrive on masonry surfaces.
  • Efflorescence - salt deposits caused by water dissolving salts within masonry & depositing them on the outside of the wall are a key indicator of water ingress. While not damaging, it can create a real eye-sore on masonry surfaces of all ages.
Salt efflorescence on a brick wall

Masonry Sealers

This is where masonry sealers come in. Masonry sealers & other similar treatments aim to prevent the water absorption of masonry, preventing the moisture from being held in the brickwork. By preventing water absorption, the masonry is protected from all of the side effects that the moisture can have.

Unfortunately, in the UK there is a lot of conflicting information regarding masonry sealing. While masonry sealers prevent water absorption, they do this by creating a clear film on the surface of the masonry. This film can impact the breathability of the masonry, preventing water vapour from freely passing through the surface. By preventing this breathability, any moisture that naturally builds up within the structure from condensation will become trapped, along with any moisture that finds its way underneath the paint film from any hairline cracks.

Eventually, after the trapped moisture causes significant damage to the masonry & extensive internal damp problems, the film of the sealer will break under the pressure. This will leave the masonry unprotected and in a worse state than it started in. Imagine wrapping your exterior masonry walls in a plastic cling film. This would trap moisture in the exact same way as a masonry sealer.

A masonry sealer should only be used if you are looking for a short-term solution to water ingress on a small section of masonry. Even in this scenario, it should be treated with caution.

Masonry Creme

When opting for a waterproofing treatment, you must ensure that it is highly breathable, as not to impact the natural breathability of the masonry.

Breathability is measured by an SD rating, which is a calculation of how easily water vapour can travel through a surface. A surface or coating is breathable when it has an SD rating of 0.5 or below, as stated by industry standards.

This requirement of high breathability & waterproof properties is why we developed our super hydrophobic nano-technology here at ProPERLA. Our technology was developed to chemically bond and impregnate into masonry surfaces, rather than create a film on the surface. This lines the pores of brick, concrete, stone & other mineral surfaces without sealing them, preventing water from absorbing into the surface but still allowing water vapour to travel through.

We took our ProPERLA Masonry Creme to independent UKAS accredited laboratory Lucideon to ask them to test our Masonry Creme for durability, water resistance, heat retention & breathability. In a 25 year accelerated weather test, Lucideon found that after the 25 year period, there were no signs of deterioration in performance or appearance.

The treatment was found to prevent 96% of water absorption, even after the 25 years. Furthermore, in breathability tests was found to have an SD rating of 0.03, demonstrating the treatment is highly breathable.

In the test for heat retention, ProPERLA Masonry Creme was found to result in the treated wall being on average 6°C warmer when compared to an untreated masonry wall. For this reason, ProPERLA Masonry Creme was verified by the Energy Saving Trust for its ability to help reduce energy bills & maintain higher household temperatures.

A demonstration of the heat that is transferred through exterior walls when left untreated.

How Do I Treat My Masonry With ProPERLA?

Both ProPERLA Masonry Creme and our coloured system ProPERLA Facade Coating are specialist technologies that must be applied by experts in order to ensure their performance.

We have a number of approved ProPERLA applicators up and down the UK who have attended our rigorous training program to ensure they apply the treatments to the highest level. To find an approved ProPERLA applicator, simply type your postcode in our applicator finder tool and find your nearest applicator, who can carry out the treatment for you.

ProPERLA Masonry Crème

A surface treated with ProPERLA Masonry Crème will insulate mineral building materials by reducing water absorption by more than 95%. The product chemically bonds to the surface, penetrating up to 17mm to create an invisible insulation barrier.

  • Chemically reacts and actively bonds to a range of substrates including brick, stone, concrete and sandstone
  • Tests have demonstrated that when ProPERLA Masonry Crème is applied to clay bricks, it slows down thermal heat loss by up to 76.83% .
  • Manufacturers guarantee of 20 years & proven performance of 25 years
  • Dries clear-  it does not alter the exterior appearance of the property
  • Benefits from an SD (breathability rating) of 0.03- a coating is considered to be breathable if it has an SD value of 0.50.
  • Keeps properties clean and attractive - dirt particles are washed away with rainfall
  • Makes it difficult for the growth of moss, algae or lichens
  • Helps to prevent discolouration, efflorescence & frost damage
  • Unaffected by UV rays
facade coating

ProPERLA Facade Coating

A highly technical two-coat coloured facade coating which mimics the self-cleaning capabilities of the lotus leaf and helps to maintain the freshly painted appearance of the property.

  • Chemically reacts and actively bonds to mineral substrates
  • Choice of colours available
  • Super hydrophobic
  • Manufacturers guarantee of 10 years but the product has a proven performance of 25 years
  • Benefits from an SD (breathability rating) of 0.06- a coating is considered to be breathable if it has an SD value of 0.50
  • Keeps walls clean and attractive - dirt particles are washed away with rainfall
  • Discourages discoloration and prevents salt efflorescence.
  • Discourages growth of moss, algae and lichens
  • Helps to prevent frost damage

Frequently Asked Questions

Q. How do I become an approved applicator of ProPERLA products?

To ensure our products are only applied by trained experts, we ensure that applicators attend our training course in order to become an approved applicator of ProPERLA products. Why not read more about our training course if you would like to be able to offer ProPERLA technology to your clients?

Q. Does ProPERLA Masonry Creme alter the apperance of masonry?

Unlike masonry sealers that can leave a 'sheen' on brickwork, ProPERLA Masonry Creme does not alter the appearance of masonry in any way. This is because it does not form a film on the surface of the masonry, instead penetrating into the brickwork and waterproofing it from the inside.

Q. Should you apply waterproofing treatments to new-build properties?

While new bricks are not as porous as weathered bricks, after a period of time they will become weathered and will start to uptake more and more water. By applying Masonry Creme, you are protecting & investing in the long-term protection of the building. After all, prevention is much easier than restoration.

Q. Do I need to seal brick & masonry before painting?

A common misconception regarding penetrating damp prevention & waterproofing is that you have to seal the masonry before painting. By sealing the masonry, you are creating a water repellent layer that will prevent the paint from adhering to the masonry. If you want a waterproofing treatment but also want to then paint this, simply opt for a waterproofing wall coating like ProPERLA Facade Coating. This contains the same super hydrophobic technology but in a coloured form, removing the need to apply two separate coatings.


Want to speak to one of our technical advisers for further advice on roof cleaning? Send them an email to info@properla.co.uk & one of the team will be on hand to assist you with any questions you may have.


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