Water penetration into your roof structure can cause damp, mould, leaks, and even structural damage. These issues are especially common in the UK, where we tend to have persistent wet weather. Making your roof tiles waterproof can help to protect your roof, and your property, and there are a few different methods that can achieve this.
Many people assume that roof tiles are designed to be waterproof. It is true that one of the purposes of a roof is to keep the property dry, but traditional roof tiles are not fully waterproof at all. In fact, they are naturally porous.
Clay tiles are the most absorbent of the two. Clay tiles can absorb up to 25% of their weight in water, whereas concrete tiles can absorb up to 15% of their weight in water. Old concrete tiles, however, will become more porous as they age.
Roof tiles are installed in such a way that the water usually won't seep into the roof's structure, including the roof beams and other elements. However, the absorption into the tile material itself will start to create issues over time.
In the colder months, water absorbed into the roof tiles will freeze and expand. This creates micro tears in the roof tile. As this cycle continues, the tears will gradually get larger, which can eventually create large enough holes for water to penetrate the roof's surface.
Wet or damp tiles create the perfect breeding ground for moss, algae, and lichen growth. The problems that this growth causes aren't just limited to aesthetics.
Plant material traps moisture at the roof's surface, which can make issues with water absorption even worse. Moss can also root into the tile, making it degrade more quickly.
The plant growth can create micro-tears, which absorb extra water, and get larger over time.
Read our article on "How to clean roof moss".
If a tiled roof has absorbed a large amount of excess water, this will increase its overall weight. The roof structure would not have been designed to carry too much additional weight, and over time, this can lead to sagging and other serious structural issues.
This is especially the case if the wooden beams supporting the roof are exposed and absorbing excess moisture.
There are various strategies that can be used to increase a roof's waterproofing capabilities. Some of these happen during the roof tiles' construction, but other strategies can be put in place after the roof has been installed.
Some manufacturers apply a water-resistant coating to roof tiles during production. This helps to reduce the tiles' porosity. These coatings can wear off over time, however, and may require maintenance to retain their waterproofing.
A waterproof roof coating is applied once the roof is in place. They can be made out of a variety of materials, including acrylic, silicone, and polyurethane. They are a roof paint that dries to a waterproof coating.
Roof coatings can be a relatively cheap and easy-to-install option, and they will seal small cracks and holes. They tend to be flexible, so they will expand and contract with the house as the temperature fluctuates, and most are UV-resistant. This helps to prevent the degradation of the roof tiles due to UV damage.
Have a look at our post "Does roof coating stop leaks".
Roof sealers are similar to roof coatings, but they do differ in some key elements. A roof coating creates a waterproof layer that sits on exterior surfaces to prevent water from reaching the material underneath. They also tend to be coloured.
Sealers, on the other hand, are clear and do not create a surface coating. Instead, they seep into the pores of the roof tiles to seal them from within.
Because of this difference, sealers allow you to maintain the natural appearance of the roof. They also have superior breathability, allowing water vapour to more easily escape the building.
They don't, however, last as long as roof coatings and will require reapplication every few years. In contrast, a roof coating can last for 15-20 years, or more.
Unlike a roof coating or roof sealer, a waterproofing membrane is placed underneath the tiles instead of on top of them. Because of this, installation is a more extensive process. For new roofs, the waterproofing membranes just need to be installed before the tiles are laid. For older roofs, the tiles will need to be temporarily removed beforehand.
There are several different types of roofing membranes, and they each work well for different roof types. These include:
They are highly durable and help with temperature and internal moisture control, but they are more expensive and time-intensive to install.
If you've noticed that your roof tile is absorbing too much water or you have small leaks, waterproofing could be the solution for you. At Roof Wash Team, we are dedicated to ensuring that every client's roof is protected for years to come.
Our experienced team will assess the current condition of your roof. For example, they will note if you need any roof tiles fixed or if the seals around your roof windows are intact. These improvements need to be made before any waterproofing can begin.
Then, we will work with you to find the best waterproofing method for your tiles, and will install it to a high professional standard, preserving your roof and extending its life.
Roof tiles can be made waterproof by applying a roof coating or roof sealer. Other methods like roof membranes protect the roof from moisture without waterproofing the tiles themselves.
