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Yes, you can repair an asphalt roof almost all of the time. An asphalt roof should last beyond any guarantees provided upon installation if it is maintained correctly. But if any problems do begin to occur with an asphalt roof in nearly all cases it can be repaired by a professional asphalt contractor.
It is a very rare situation when an asphalt roof is not able to be repaired. An asphalt roof repair is nearly always possible. However, a situation where an asphalt roof would need replacing is when there are no core vents in place. This is a problem with older roofs where a concrete substrate would have a screeded covering. The reason for this was to create falls in the roof to assist with the drainage of rainwater.
What happens here is the water in the screed becomes forced downwards into the property or begins to breakdown the mastic asphalt membrane. Now core vents are used in roofing systems to dry out the screed and to allow the roof to breathe. This removes the problem of water being forced down into the building being waterproofed or breaking down the mastic asphalt. If you do have a roof without core vents the best option would be a new asphalt roof.
Below we will look at the most common reasons for an asphalt roof repair being required.
Bumps: This is when the asphalt blows and forms a bump. The reason for this is moisture gets trapped underneath the asphalt membrane and when it tries to escape, it forms a bump. If you see any bumps on your asphalt it is a sign of water ingress and should be fixed immediately before more serious problems develop.
Blistering: Blistering is caused in the same way as bumps. The only difference is blistering is when there are multiple bumps in an area. It looks like the roof has multiple blisters hence the name. Just like with bumps this problem should be fixed as soon as it is identified.
Cracks And Splits: Obviously any cracks and splits are serious problems in a waterproofing membrane as the roof is exposed to water ingress. Cracks and splits can form in an asphalt roof in several ways. The first way is when the moisture in bumps or blisters exerts so much pressure on the asphalt, if finally breaks the surface.
Another way cracks can form is through impact damage. This is especially likely on roofs which are heavily. What happens here is a heavy object is dropped on the asphalt and causes a crack or indentation. Extreme cold temperatures can cause cracks in an asphalt roof. This is a very rare phenomenon.
Another common cause of cracks in mastic asphalt is from the cycle of thermal movement. What happens here is the constant expansion and contraction as temperature change begin to wear down the asphalt and cracks eventually form. Solar reflective paint is a great way of minimising the chances of cracks happening due to thermal movement. It reduces the roofs surface temperature and minimise the temperature fluctuations the asphalt must suffer.
Slumping: This occurs when in the summer month the radiation from the sun bakes the asphalt and causes it to lose form. This is especially problematic around lead flashing and upstands as space can be made for water to penetrate. The way to reduce the probability of this happening is solar reflective paint. This does not mean just on the asphalt but also on any lead flashing which covers asphalt.
Failing Flashing: As mentioned above it is advisable to paint any asphalt which is covered by lead flashing with solar reflective paint. The reason for this is lead is a conductor of heat. And will heat the asphalt below. This makes slumping more likely. Additionally, when lead becomes hot it is more malleable which can lead to a space opening where water ingress can occur. Another problem which can occur with lead flashing is when the mortar starts to break down causing the flashing to pull away. The reason for this can be thermal movement or simply age. Although failing flashing is not directly related to the asphalt failing in most cases, it does lead to the roofing system failing and it must be repaired.
Failing Upstands: Upstands can fail due to not being cut into a chase. Or through the mortar attaching them to the wall breaking down due to thermal movement or age. In both cases repair work will be necessary.
Oil Damage: Oil breaks down mastic asphalt if you notice any oil on an asphalt roof this must be repaired as soon as possible This is most often seen around commercial roofs with plant machinery. Like most asphalt repairs oil damage is fixed by removing the defective area using the ‘hot poultice’ method.
Cracked Render: Although nothing to do with the asphalt roofing system itself. A crack in the render is a problem for the substrate the roof protects. What happens here is rainwater hits the wall where the render is cracked then runs down the back of the render and under the roofing system. If this is not addressed leaking will eventually occur.
Split Asphalt Collars: Soil vent pipes are finished with mastic asphalt collars. This is where mastic asphalt tanks the pipe approximately half way up. The purpose of this is to stop water getting between the pipe and the asphalt roof. Thermal movement can cause the pipe to pull away from the asphalt. The problem with this is a gap occurs where water can penetrate. If a mastic asphalt collar has become defective it is imperative to fix it immediately.
If you would like any more information or a quotation regarding the repair of an asphalt roof please get in touch with us or call us now on 01277 375 511. One of our friendly team of asphalt specialists will be happy to help.