Asphalt Flat Roofs

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asphalt flat roofs

Asphalt flat roofs

Asphalt flat roofs are one of the best roofing materials for a flat roof and generally are considered to have a life of 30 to 40 years, that is assuming they are laid correctly and detailed correctly.

Problems we have seen with asphalt roof deckings

One of the most important things with asphalt is to ensure that it sits on a firm decking. We have found that asphalt tends to work best when sat on a concrete decking, whereas if it sits on a timber decking it can have some deflection, which leads to cracking and ultimately to dampness getting in the property.

asphalt flat roofs

Plants growing out of asphalt are
never a good sign!

Asphalt on permanent metal shuttering?

We have not personally come across this and would be interested to see if it can be done or not. There would be quite a lot of movement within a permanent shuttering and therefore this would have to be planned for within the design.

Asphalt roof problems things to look out for

No solar reflective paint

Some asphalt roofs have a solar reflective paint that is silver or white in colour. This does tend to throw the inexperienced person as to what the roof actually is. This is a paint applied over the top of the asphalt to help reduce damage from the sun's rays. Unfortunately, this can also hide problems unless you look carefully.

asphalt flat roofs

Asphalt with blisters

Asphalt blistering

Exactly like a blister on your finger, blistering can occur to asphalt. If this is found it needs to be cut out and repaired, because again, exactly like a blister on your finger, it can burst and crack open and again ultimately allowing dampness into the property.

asphalt flat roofs

Close up of asphalt blistering


This occurs where the asphalt literally appears like a crocodile's skin. You need to make sure that the crocodiling is in the asphalt rather than in the paintwork. This needs to be cut out and repaired.

asphalt flat roofs

Asphalt with crocodile type pattern

Cracking to asphalt roofs

Where there is some movement, or poor detailing, cracking occurs. This leads ultimately to water getting into the structure.

Water sitting on asphalt roofs

Whilst an asphalt roof can withstand water sitting upon it probably longer than most types of flat roofs, it does ultimately start to damage it. The beauty of asphalt is that you can, to some extent, amend the detailing by applying further asphalt on top of the original.

How is asphalt applied?

Whilst specifications do vary, generally the asphalt is warmed up and
applied hot and literally put on with a trowel onto the roof in two or
three coats.

asphalt flat roofs

Asphalt to steps, which is on the move,
but do you know why?

Asphalt detailing around roof lights

As found that sometimes the asphalt detailing around roof lights can be a weak area, possibly because a roof light is literally an opening in the roof and may deflect slightly more than the rest of the roof, particularly if the water ponds around the roof light, which it often seems to do.

asphalt flat roofs

Ponding to asphalt where the fall is
insufficient to take the water away

Independent surveyors

If you truly do want an independent expert opinion from a surveyor with regard to roof windows, roof lights, velux roofs, dormer, dormer roofs, roof problems, chimneys, surveys, building surveys, structural reports, engineers reports, specific defects report, structural surveys, home buyers reports or any other property matters please contact 0800 298 5424 for a surveyor to give you a call back.

If you want independent commercial surveying advice please read the following

If you have a commercial leasehold, freehold, etc, then you may wish to look at our Dilapidations Website at and for Disputes go to our Disputes Help site .

Written to create motion!

We hope you found the article of use and if you have any experiences that you feel should be added to this article that would benefit others, or you feel that some of the information that we have included is wrong then please do not hesitate to contact us (we are only human).

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We have produced the following articles on roof issues:

Roof Problems
Common Pitched Roofs
Not So Common Pitched Roofs
Flat Roofs
Leaking Flat Roofs
Leaking Dormer Roofs


If you would like further advice on roofs, roof problems, roof repairs, roof materials, commercial surveys, building surveys, structural reports, engineers reports, specific defects report, structural surveys, home buyers reports or any other property matters then please phone 0800 298 5424 for a friendly chat.