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Should I Repair Or Replace My Asphalt Roof?

An asphalt roof which is properly maintained should last way past its guarantees. However, if your asphalt roof is showing signs of failing there is a very high probability it can be easily repaired.

Let’s first look at the maintenance of an asphalt roof. We all know the saying prevention is better than cure. And this is true with asphalt roofs as well. The best way to maintain an asphalt roof is to have roof maintenance carried out every 3 to 5 years. This means applying a new layer of solar reflective paint across the entirety of the roof including the flashings and carrying out any minor repair works necessary. By looking after an asphalt roof, you can have a roof which last in excess of 50 years.

Repairing an Asphalt Roof

Asphalt roof repairs are easy to carry out making an asphalt roof a very good long term investment. An experienced asphalt expert will easily identify parts of the roof in need of repair and carry them out with the minimum of fuss.

Typical reasons repairs need to be carried out on an asphalt roof:


Bumps which are sometimes referred to as blows are like big bubbles beneath the surface on the asphalt. These bumps are extremely easy to spot on a roof and should be dealt with promptly. The cause of these bumps is water being trapped in between the substrate and the asphalt. What happens is in the summer the water tries to evaporate and as it is pulled to the surface it pushes on the asphalt and the big bubble is created.


Blistering is caused in exactly the same way as bumps. The term blistering just means there are multiple bumps in the mastic asphalt.

Cracks and Splits

It is common for cracks and splits to occur when bumps are not repaired. The only difference between a bump and a blister is that the actual surface of the bump has now split or cracked open. This is a problem as there is an opportunity for water ingress to arise.

Cracks can also appear due to the repeated cycle of the sun heating the asphalt causing expansion then the asphalt contracting in colder temperatures. Eventually this repeated stress on the asphalt roof will lead to cracks and splits occurring.

This problem can be made even worse in cold conditions as the water will freeze causing an expansion of the crack or split. The result will be a larger crack and a vicious cycle of the crack or split deteriorating further.


Slumping occurs when in the summer months the sun heats the asphalt causing it to soften and lose its form. This can be a problem for a number of reasons. The asphalt can slump away from lead flashing resulting in a space being made where water can penetrate.

Upstands De-bonded from Wall Details

An upstand slumping is another place where the opportunity for water ingress can develop. This will happen as the mastic asphalt upstand will pull away from the brickwork leaving the gap between the brickwork and the roof exposed.

Collars Split and De-bonded from Soil Vent Pipes

Soil vent pipes require a mastic asphalt collar to waterproof the point where the pipe meets the roof. This is done by tanking the pipe in mastic asphalt approximately half of the way up. Over time due to thermal movement these collars can split leading to their being an opportunity for water ingress.

Oil Damage

Over time various parts of plant machinery which reside on the mastic asphalt roof will need to be repaired. Various tradesmen will go up to carry out these repairs. Unaware that oil is damaging to mastic asphalt they will carry out their repair work but spill oil on top of the mastic asphalt.

Failing Flashing

Flashing can fail in a number of ways. Overtime thermal movement pulls the lead flashing away from the brickwork. This causes stress on the pointing which connect the brickwork to the wall. Once this mortar gives way there is the chance for water ingress. Note this would be a problem on any flat roofing system and is not exclusively a problem encountered with mastic asphalt roofing. Another common problem which occurs with lead flashing is the where the lead flashing meets the asphalt. As the sun shines on the lead it conducts the heat.

Not only does the lead becomes extremely hot and malleable, the asphalt is also becoming extremely hot which can lead to slumping. The solution to this is to apply solar reflective paint to both the lead flashing and the asphalt covered by the lead flashing. This will not remove the problem but it will vastly reduce it.

The Rare Circumstances in Which you Would Need to Replace Asphalt Roof

There are very few circumstances in which an asphalt roof would have to be replaced. In nearly all cases asphalt roof repair is the very best option to take. One of the rare occasions where an asphalt roof replacement would be necessary is when there are no core vents in place and the water in the screed is being forced downwards into the property or causing the asphalt to breakdown.

No Core Vents in Place: Causing the Asphalt to Breakdown or Water to Be Forced into the Premises

Many years ago, a concrete substrate would have a screeded covering. The reasons for this were:

• 1. To create falls into the roof encouraging the rainwater to disperse to the outlets.

• 2. To cover a rough surface that would not detrimental to the 20mm asphalt coverage.

Core vents1 were introduced to dry out the screed2 allowing the roof to breath without causing damage. If this wasn’t put in place the water in the screed would either be forced downwards into the premises or in time cause the asphalt3 to breakdown and thus leaving no option but to replace.

If you do find yourself in need of an asphalt roof replacement you can find out all about the process of asphalt roofing by clicking the link below:

Or if you have any questions regarding the condition of your asphalt roof and whether it needs to be repaired or replaced you can contact us on 01277 375 511 or get in touch via our website by clicking here. We have a team of asphalt surveyors including members with an abundance of expertise with a knowledge base accumulated through over 40 years in the asphalt trade. Making it certain you will receive the best possible advice for your own unique situation.

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