How to repair a flat roof. Depending on the nature and scale of the damage and the type of roofing installed, a flat roof can be repaired in several ways. First identify the source of the leak and locate the damaged area. Prepare the surface for a patch repair on a rubber roof and apply an EPDM patch to a clean, primed surface. Seal cracks in concrete roofing using liquid rubber for the best results. Extensively repaired flat roofing should ideally be removed and replaced.

Repairing a flat roof can often be a simple process for a competent DIYer. How straightforward it will be will depend on the nature of the damage and the type of roofing materials you have installed. If you find you are repeatedly repairing the same flat roof, we recommend you remove and replace the covering. This is for cost effectivity and also to maintain the integrity of the roof deck and timbers.
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Assessing your flat roof repair
Leaks in flat roofing are often identified initially from the inside. Once the common signs appear, such as a damp patch or water spots on the ceiling, a musty smell or the appearance of mould or condensation, it is important to locate the source of the leak as quickly as possible before further damage occurs.
If you can access your flat roof safely, carefully inspect the covering material for any visible signs of damage. This might look like:
- Bubbles on the surface of felt or membrane
- Ponding water on the surface
- Cracks
- Missing or damaged flashing
- Broken or clogged gutters
Clogged gutters are a surprisingly common cause of leaks in flat roofing. When rainwater cannot effectively drain away, gutters overflow and water can get inside. Also bear in mind that water can track down or across roof timbers, so external signs may not necessary correlate exactly with internal water spots.
Once you have located the damage, you can assess the repair. If you’ve caught it early enough, it may only require a patch repair, but if the damage is more extensive and the timbers are affected, it may be wise to seek a professional assessment. Carry out a temporary repair to prevent further damage or seek an emergency repair solution.
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Handling a temporary or emergency repair on flat roofs
If an emergency repair is needed, PermaRoof UK’s Emergency Roof Repair product is ideal. A pre-mixed, liquid rubber solution, P500 can be quickly and easily applied in just one coat to a wide range of surfaces, such as:
- Timber
- Concrete
- Felt
- Bituminous coverings
- EPDM membrane
- Metal panels
This offers a quick, yet long-lasting approach for a minor flat roof repair or can provide a reliable temporary solution while you wait for planned works, assessments or quotations.
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Applying Emergency Roof Repair
Prepare the damaged area and remove any grease or oil spots using a solvent-free cleaner. Using a good paintbrush, apply the Emergency Roof Repair liquid rubber to the repair zone. Watch our video guide below to see how fast and easy it is:
How and when to call in the professionals
If the flat roof repair feels beyond your DIY skills or confidence, it is time to call in a professional roofer to assess the damage. We can help you connect with a reliable, time-served local roofer through our Nationwide EPDM Installer Network.
Repair or replace flat roofing?
When flat roof repairs become a regular task, particularly if you find you’re revisiting the same spot, it may be time to consider replacing the roof covering. Modern materials, such as EPDM, offer a longer-term approach to waterproofing than traditional coverings, and can be faster and easier to install.
If left, old or excessively repaired flat roofing can become much more susceptible to failure. This can increase the likelihood of emergency repairs and risks damage to the roof deck and timbers.
Using a rubber membrane to replace outdated or ill-performing flat roofing can often be more straightforward than repairing the roofing and much more cost-effective over time. If you decide to replace your flat roof materials instead of repeatedly repairing them, EPDM rubber membrane is the perfect approach for DIY.

Flat roof replacement kits at PermaRoof
PermaRoof UK stocks a wide range of EPDM roofing kits to make the experience even easier. Our kits are available in standard sizes or can be tailored to your exact needs. Everything is included:
- Firestone RubberCover membrane
- Adhesive
- Sealant
- Trim
- Fixings
We also sell one-piece EPDM kits for shed and garage roofing.
Preventing flat roof repairs
Preventing leaks is always better than repairing your flat roof, so make sure you keep a regular eye out for the signs of a failing roof in advance and stay on top of routine maintenance.
- Ponding water following heavy rain
- Bubbles forming on the surface during hot spells
- Remove fallen branches or debris
- Ensure gutters are kept clear and free flowing
- Visible cracks
- Loose gutter sections
- Changes to flashing, fascia boards or soffits
Here at PermaRoof UK, we support all our customers and answer a variety of flat roofing questions every day. If you have a question, please visit our FAQs page, give us a call on 01773 608 839 or use the live chat for a quick query.
Other articles about flat roofing:
What is Liquid Waterproofing?
‘What is Liquid Waterproofing Membrane?” is a question we are routinely asked at PermaRoof UK. We
Ask the Experts: How to Fit a Rubber Roof
‘How to fit a Rubber Roof” is one of the top questions we get at PermaRoof
Leaking Flat Roof? What Are Your Options?
A leaking flat roof can go from 'minor drip' to serious damage very quickly. Whether it’s over a
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Permaroof (UK) LTD
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Permaroof UK® Ltd
Unit 1
Westway
Cotes Park Industrial Estate
Alfreton
Derbyshire DE55 4QJ
Tel: 01773 608 839
Fax: 01773 608 408
Email: Click here
Registration No. 4109502
VAT No. 764 2785 00
Permaroof (UK) LTD
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