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To fix a leaking asphalt roof you must identify the source of the leak. But before you do this the first step is to contain the leak. If there is water coming through the roof you must clear the area which is getting wet. And then place a bucket to catch the falling water. If the leak is severe, you should get a second bucket to replace the first one when it becomes full. Then, you should dry any wet on the floor using an old towel or a mop. Now you have contained the leak you can start identifying the source and the cause of the leak. Most of the time it would be advisable to contact a professional roofing contractor to do this for you.
Finding the source of a leak on a flat roof can be a challenging process. The first step is to look for any obvious signs of damage to the asphalt. The most obvious signs of damage on an asphalt roof will be bumps, cracks and splits. When any of these issues occur it is likely the roof will be suffering from water ingress. If you identify bumps. cracks or splits in your asphalt flat roof, there is a high probability this is where your leak is coming from.
Another sign of a potential problem is if the roof does no have solar reflective paint, or solar reflective paint has not been applied to the roof for more than 5 years.
The problem which is most common here is thermal movement. This is when the roof reaches high temperatures in the summer and as it contracts as the temperature cools then expands again as it rises. This places stress on the asphalt and can causes crack. The roof itself is not the only areas where thermal movement can cause problems. Any upstands or flashings around the roof can begin to pull away from the wall. This happens as the thermal movement puts pressure on the mortar pointing connecting the upstand or flashing to the wall. Once this breaks down water can penetrate behind the flashing or the upstand and underneath the waterproofing and develop in to a leak.
Another problem related to the lack of solar reflective paint is when it is not applied to lead flashings which cover the asphalt roof. As both lead and asphalt are conductors of heat if there is no solar reflective paint applied to the flashing, the flashing and asphalt get to extremely high temperatures. This can cause a problem known as slumping. As the name suggests slumping causes the asphalt to slump, this can lead to a gap forming between the lead flashing and the asphalt roof. This can obviously lead to the potential of water ingress occurring.
Oil damage is another potential reason for a leaking asphalt roof. This is especially common on commercial asphalt roofs. What happens here is normally completely accidental as a tradesman will go up to repair plant machinery, a soil vent pipe or an air handling unit, completely unaware of how oil damages asphalt. As they carry out oil is spilt on to the asphalt. This oil starts to break down the asphalt which over time will lead to cracks and indents in the surface. This will result in water ingress and in time leaks.
Rendering is another area which can cause a leak in an asphalt roof. This problem is no fault of the mastic asphalt itself. What has happened here is when it rains water hits the rendering which has failed and runs down the rendering and underneath the roofing system. Some thermal cracks in render may only be able to be seen at certain times in the day. This water getting underneath the roofing system will in time cause leaking.
Once the source of the leak in an asphalt roof has been identified it needs to be fixed. In almost every case a leaking asphalt roof can be repaired. To learn more about cases where an asphalt roof may need to be replaced click the following link:
If there is a problem with the asphalt roof itself. This would be in the form of cracks, splits, bumps, oil damage or blisters. If this is the case the "hot poultice" method would be used for the repair. The defective area is heated to loosen the asphalt then with a hammer and bolster a cut is made around the perimeter of this area. Once this is done a shovel or pick is used to remove the defective area. If there is any damp this is dried and the surface is primed. Next the perimeter is cleaned to form a break joint. Next, mastic asphalt is re-applied and a fusion joint is created between the new and old asphalt. Once this is done the surface is painted with solar reflective paint and the repair is complete.
A rendering problem is not directly related to the mastic asphalt. To fix this you will need to get in contact with the appropriate rendering expert this will depend upon what type of render you have whether it is sand and cement or monocouche rendering. Once a professional rendering company has been as rectified the source of the water ingress, your repair should be complete. If you still encounter leaking after this is rectified, your roofing system has another problem aside from the rendering. If this is the case you should get a leak detection survey.
If the mortar connecting the upstands or flashing to the wall has broken down. The defective upstand of flashing will have to be removed (and replaced if necessary). The area behind the upstand of flashing should be dried out and re-primed. Once this is done the flashing or upstand should be replaced. And then, new sand and cement mortar should be applied. In future an annual roof survey would be advised to ensure early signs of any mortar breaking down are identified and fixed. It is recommended to cover any upstands or flashings with 2 coats of solar reflective paint. In the case of asphalt which is being covered by flashing it is also important to ensure this asphalt is covered with solar reflective paint.
If you have a leaking flat roof you should follow the following steps:
1) Clear the area where water is coming through your roof into your property.
2) Contain the leak, with a bucket.
3) Dry the area which the leak has made wet.
4) Identify the source of the leak by looking for problem areas (it is better to call an asphalt professional to do this)
5) Carry out the appropriate repair work to the asphalt roof.
If you would like a quotation or any information on the repair of a leaking 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.