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The Truth About Waterproofing A Roof

Waterproofing a roof

Maintaining the integrity of your home is one of the most important aspects of being a homeowner and can be one of the most stressful. We all want to keep our home protected, by how do you do this, and especially without breaking the bank.

This is where roof waterproofing treatments come in, as they provide an effective solution for any roof, whether new or old.

What is a roof waterproofing treatment?

Firstly let's establish what exactly a roof waterproofing treatment is. These treatments come in a range of forms, that can generally be put into two categories; roof coatings and roof sealers. These treatments are often called different things, however essentially a roof coating is a coloured roof paint, while a roof sealer is a clear, invisible waterproofing treatment that does not alter the appearance of the roof.

Roof waterproofing products are designed to prevent moisture from absorbing into a roof tile. This is contrary to popular belief, with many homeowners believing that their roof is already waterproof. The truth is that roof tiles, like most building materials are porous, meaning they absorb some level of moisture. This moisture causes significant damage to roof tiles, causing cracks along the tiles, allowing moss to grow, and generally weakening the strength of the roof.

Untreated roof tiles suffer from a range of problems, including:

  • When a roof is left untreated, moisture can find its way into any gaps between roof tiles, which when it freezes expands, causing hairline cracks in the roof tiles to grow larger.
  • High moisture conditions are perfect for moss to grow, which lifts roof tiles away from each other when it grows, increasing the likelihood of damage.
  • UV degradation can cause discolouration of the roof tiles

This is why waterproof technology has been developed for roof tiles, in order to help protect and restore new and old tiles.

The truth about waterproofing a roof

All waterproof technology has come under fire over the years, with roof waterproofing treatments being no exception. This bad press has come from the introduction of the term 'sealer'. A traditional sealer waterproofs a surface by 'sealing' it, thus not allowing water to absorb into the surface. This attempts to prevent damage and decay that moisture causes over time. Unfortunately, many of these sealers over the years, and still today, while they prevent moisture from entering the material, also prevent moisture from escaping from inside the sealed surface. This traps moisture inside a property, which can be hugely damaging to the material and can cause problems such as damp.

Due to these non-breathable roof waterproofing treatments, many have been led to believe that all of these products are 'sealants' and therefore will be hugely damaging when applied to a roof.

This is why the latest roof waterproofing technology has been developed, in order to ensure that the breathability of the roof is not compromised once the waterproofer is applied. To be considered breathable, a waterproofing treatment must have an SD rating of below 1. If it has an SD rating of below 1, then water vapour can freely breathe out of the roof, maintaining dry building materials.

If a roof waterproofer or roof sealer does not have an SD of below 1, then you must avoid this completely. It will simply trap moisture inside your property, simply making any damp problems worse, as we have discussed.

What's the best breathable waterproofing treatment?

The super hydrophobic technology developed by ProPERLA is the most advanced waterproof technology available in the UK today. 

The super hydrophobic technology consists of the latest nano-technology that lines the pores of exterior surfaces without sealing them. This is achievable as water vapour is small enough to breathe through the treatment, while water particles are too large, thus why they are repelled.

Waterproofing a roof using ProPERLA's super hydrophobic technology has a number of other benefits:

  • Creates a self-cleaning surface as dirt particles are repelled with any rain fall 
  • Extends the lifespan of roof tiles as moisture is the biggest cause of roof tile failure
  • Makes it difficult for the growth of algae, lichens or moss on the roof tiles
  • Helps to prevent discolouration and salt efflorescence

ProPERLA's super hydrophobic technology is available for a range of materials such as roofs, exterior walls, wood & paving. In particular, there are two forms of waterproofing products for roofs; ProPERLA Water Repellent and RENOTEC Roof Coating.

While ProPERLA Water Repellent is a clear, invisible system that helps to protect roof tiles from water damage, RENOTEC Roof Coating is a popular choice with homeowners who want to transform their roof tiles, without paying for a hugely costly re-roofing of their home, which can cost significantly more than simply coating the tiles.

Both of these products come with a 10 manufacturers guarantee as they have been independently tested and certified following a number of tests.

ProPERLA Water Repellent has been manufactured in accordance with DIN 4108, which is the European rating for water repellency. and certified in accordance with EN1504-2 : 2005, confirming depth of penetration, water absorption & resistance to alkali.

RENOTEC Roof Coating has achieved the following quality standards;

  • DIN EN ISO 53054 - Tensile strength
  • DIN EN ISO 7783-2 - Water vapor permeability
  • DIN EN ISO 1062/3 - Water impermeability
  • DIN EN ISO 4624 - Pull-off test for adhesion

These results confirm that the roof coating not only remains flexible to resist tearing, but it also maintains full breathability, is water repellent and offer superb adhesion to roof tiles.

RENOTEC Roof coating

The ultimate waterproof paint for roofs

  • Available in a range of popular exterior colours
  • Super hydrophobic
  • Highly breathable
  • Self-cleaning
  • Discourages moss, algae & lichens
  • Helps to extend the lifespan of the roof tiles
  • 10 year manufacturer's guarantee
Renotec Roof Coating
ProPERLA water repellent

The ultimate clear roof waterproofer

  • Creates an invisible protective barrier
  • Super hydrophobic
  • Highly breathable
  • Self-cleaning
  • Discourages moss, algae & lichens
  • Helps to extend the lifespan of the roof tiles
  • 10 year manufacturer's guarantee
Water Repellent

RENOTEC Roof Coating

Moss on roof


moss on roof tiles


moss removed


moss on roof tiles removed


RENOTEC is available in seven popular colours that are designed to match any property. Our Red Brown & Rustic shades are two of our most popular colours, as they provide a beautifully traditional look to any property. For something more modern, Anthracite & Black Blue also prove extremely popular. These shades work perfectly with white rendered properties, and can really provide a huge kerb appeal. 

Renotec Roof Colours

ProPERLA Water Repellent

While the clear ProPERLA Water Repellent does not alter the appearance of roof tiles, as with any coating, dirt and grime must be washed off before it is applied. This means that the roof must be cleaned of any moss, dirt or algae by a professional.

Once this is done, it is astonishing the difference it can make to a roof. The colour of the roof tiles beneath can provide a beautiful new look to your home, while offering a less impactful finish to the roof tiles as they will still vary in shade from one another. This is particularly useful for older properties that benefit from a more rustic finish to the roof tiles.





How to waterproof a roof

We do not advise that you attempt to waterproof a roof yourself using specialist treatment such as ProPERLA, as there are countless things that can go wrong.

We have a number of Approved Installers who have completed our ProPERLA training course, that ensures they can expertly apply our roof treatments treatments to your home. Please see our Approved Installers page here to find an installer in your area who can assess your property and provide a quotation. These companies range from roof cleaning companies to home improvement companies, who are all trained & certified to apply ProPERLA products.

We hope this guide has answered any questions you may have had regarding moss & how to prevent it. No matter whether you are a homeowner or a roof coating company. We are on hand to assist you with any question you may have.

Want to speak to one of our technical advisers for further advice on our range of roof waterproofing treatments or want more information regarding waterproofing a roof? They are always on hand to answer any questions you may have. Send them an email - info@properla.co.uk
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