For homeowners, flat roof leaks can be a big problem; not only can they cause some serious damage, but leaking roofs are also expensive to fix.
Recognising the early signs of a leaking flat roof can prevent expensive repairs, maintain the safety of your home, and increase the lifespan of your flat roof.
In this blog, we’re going to give you guidance on how to spot common signs of a flat roof leak and the steps you should take.
Flat Roof Leak Detection Tips
Water Stains on Walls & Ceilings
If you spot any brown or yellow blobs on your walls or ceilings, it could be a water stain. This is a pretty big sign that your flat roof is leaking. These stains can vary in size, but even the smallest ones can indicate a leaking flat roof and should be checked out as soon as possible.
Peeling and Bubbling Paint
When paint on your walls or ceiling is bubbling and peeling, it’s a sure sign that there is too much moisture, usually indicating that there is a leak somewhere in your flat roof. If this is left, it can cause a lot of damage, so we recommend keeping an eye on these and getting them checked out.
The Roof Deck is Sagging
If you spot the roof deck sagging, it’s a sign of quite a serious leak. When the structure of the roof soaks up too much water, it can create weak points and begin to sag. If this happens, the whole underlying structure of the roof can be weakened.
Damaged Flashings
Flashings and vents are an important part of any flat roof, as they are used to keep water out of your home. Over time, they can become rusty or crack, and vents can loosen, allowing water in. Leaks are especially common around skylights and chimneys (usually when the vents are poorly installed). If you can, regularly check the flashing and vents to look for any cracks.
Cracks, Splits, or Blisters in the Roof Surface
Sunlight exposure, temperature changes, heavy storms, and general wear and tear can all affect a flat roof surface. The surface can develop cracks that may not be too serious to begin with, but left unresolved, they can become entry points for water and let the water beneath the flat roofing membrane, which causes significant damage and is a major cause of leaks.
A Damp Smell
If you notice a musty or damp smell inside your house, it could be a warning sign that water is somewhere that it shouldn’t be, and it might be time to call in the flat roofing experts.
Pooling Water on the Roof Surface
After rainfall, if you notice that there is ponding water on your flat roof after 48 hours, it’s a sign that there might be something wrong. Water pooling also adds pressure to the surface, which can lead to leaks and structural issues. For fibreglass flat roofs, one of the most common causes of leaks is pooling water.
How to Inspect a Flat Roof for Leaks
Regular inspections are essential to catch a flat roof leak before it causes damage to your property. Start by checking the roof surface for cracks, blisters, or other signs of wear in the flat roofing membrane. Look for ponding water, which often points to blocked roofing vents or poor drainage design.
If your roof is leaking, examine the nearest walls, ceilings, and the roof deck underneath for water stains or damp patches. On the roof itself, inspect the lead flashing, expansion joints, and roof coverings for splits, loose edges, or poor detailing that could let water in.
For felt roofs, rubber roofs, or fibreglass flat roofs, remove debris and make sure drains and gutters are clear. If you see any signs of structural issues, contact a professional roofer. Quick repairs can prevent long-term water ingress.
When to Call in a Professional Roofer
Some problems go beyond what you can spot yourself. A reliable roofer can perform detailed flat roof leak detection using tools like water tests, thermal imaging, and moisture meters to pinpoint weak points in the roofing membrane.
Call a professional if you notice recurring damp smells, visible roof damage, or poorly installed roofing materials. Experienced roofing contractors can repair issues with torch-on roofing felt, bitumen primer, or self-adhesive flashing tape, depending on the roofing material used.
They’ll also check for poor workmanship, structural movement, and other major causes of leaks, ensuring your flat roofing work is watertight and built to last.
Maintenance to Avoid Flat Roof Leaks
Preventative care is the most effective way to protect your flat roof and avoid expensive roof repairs. Follow these simple maintenance tips to keep your roof watertight and in great condition:
- Clear gutters and outlets regularly by a scheduled routine gutter clearing to prevent blockages that cause pooling water and water ingress.
- Remove debris, moss, and dirt. Keeping the roof surface clean reduces wear and stops standing water from damaging the roofing membrane.
- Inspect the surface for cracks or weak points.
- Apply flat roof sealant where needed.
- Check for signs of poor installation. Look for lifted edges, splits, or bubbling; these can be a result of poor workmanship or structural movement.
- Schedule professional maintenance. A reliable roofer can inspect for hidden issues, check expansion joints, and ensure your flat roofing work remains sound.
If you think your flat roof might have a leak, contact our team today, and they can help you!
