How to Fix a Leaking Flat Roof?

July 26, 2023

A professional survey of roofing experts revealed that flat roofs, when left uninspected, are highly prone to issues like blisters, cracks, and leaks.

Such small defects can quietly turn into a major problem, damaging your interiors, insulation, and even your peace of mind. So, if you’re noticing a water stain on the ceiling or hearing that dripping sound, it’s time for your roof repair!

The good news is that flat roof leaks can be fixed and can also be prevented with the right care.

In this blog, we’ll explain how to fix a leaking flat roof in detail and when you should call a roofing contractor.

Why Do Flat Roofs Leak So Often?

Here are some of the most common reasons behind flat roof leaks.

Ponding Water – Water that collects in one spot for more than 48 hours is your roof’s worst enemy.
Cracks or Blisters in the Membrane – Over time, the roofing material (like modified bitumen, EPDM, or TPO) can develop cracks or blisters.
Clogged Drains or Gutters – If water has nowhere to go, it pools and eventually finds a way in.
Damaged Flashing or Seals – Edges and seams are weak points. If they crack, they let moisture pass in.

So, what should you do when your flat roof starts leaking? Let’s find out.

Need Roof Repair in Redding? Call Now!

How to Fix a Leaking Flat Roof? A Step-by-Step Guide

Before you plan to fix your leaking roof, make sure you do it safely. Avoid climbing during or right after rain. If you’re not confident or the damage looks extensive, call professional roof experts like Foam Experts Co.

1. Locate the Leak

Water stains inside your building don’t always line up with the source of the leak on the roof. To find the exact point of the leak, you can start by –

Checking the roof surface visually.
Looking near drains, HVAC units, and seams.
Identifying ponding spots or bubbles.

If you press gently on a bubble and water comes out, it means you’ve likely found the issue.

Foam Experts Co. uses advanced tools to detect hidden leaks. One smart method involves placing a special grid tape on the roof. If there’s moisture, the tape helps us find the exact spot, even under gravel, garden roofs, or protective layers.

2. Clean the Area

Before you can patch anything, the roof must be clean and dry. You can use –

A broom to sweep away debris
A cloth or towel to dry the area
A utility knife to remove the loose membrane if needed

Cleaning is important because adhesives and sealants don’t stick to dirt, dust, or moisture!

3. Apply Temporary Fixes (If Needed)

If it’s going to rain soon and you need a quick, temporary fix, try using:

Roofing tape or patches
Bitumen or waterproof sealant
Tarp secured with roofing nails or weights

Temporary fixes won’t last forever, but they’ll buy you some time until professional roof repairs can be done.

4. Make a Permanent Repair

You can also permanently repair the leaking roof if you’re good enough at DIY techniques.

This is where things get a little more technical, but don’t worry, we’ll break it down simply.

For Small Cracks or Holes

Use a roofing sealant or bitumen.
Spread it over the crack using a putty knife.
Press a piece of roofing fabric or mesh into it.
Apply a second layer over the top.

For Blisters

Cut the blister open (if dry), but don’t remove it.
Let water drain, then press the material back down.
Apply roofing cement on the area and strengthen it with mesh or fabric.
Cover with another layer of cement.

For Seams or Flashing

Re-seal the edges using a high-quality elastomeric sealant.
Make sure the seal is watertight all around the problem area.

Only try permanent repairs if you have some experience or feel confident doing it. A small mistake, like sealing the wrong area or damaging the membrane, can make the leak worse or cause new ones.

When Should You Call a Professional for Leaking Flat Roof Repair?

Flat roof repairs can be tricky. If you’re unsure or the damage looks serious, it’s best to let the experts handle it. You should call professionals when –

The leak is extensive or has caused interior damage
The membrane is old or deteriorating
Your roof insulation feels wet or spongy
You’ve made repairs before, and the problem keeps coming back

Just covering a leak without fixing the real problem is like using a band-aid on a broken pipe. It won’t hold for long!

Upgrade to an Energy-Efficient Roof – Contact Us Now

Still Unsure? We’ll Help You By Answering Some Commonly Asked Questions on Roof Repair

1. How often should I inspect or maintain a flat roof?

We recommend semi‑annual inspections, especially after storms, and maintenance every few years, like re‑sealing seams or clearing drains to prevent ponding water.

2. Why is the leak not directly above the water stain inside?

Water doesn’t always drip straight down. It can move under the roof surface before showing up inside, so the leak might be far from the ceiling stain you see. That’s why proper leak detection is important before the roof repairs.

3. What’s the best way to repair cracks or blisters?

Clean the area well, then apply a silicone or polyurethane patch. For extra strength, press a piece of mesh fabric into the patch before it dries.

4. Can I use sealant on an old roof until I save up for full repairs?

Yes, as a short-term fix, sealant or tape can help patch small leaks temporarily in emergencies. However, it doesn’t fix underlying issues.

5. When should I stop DIY repairs and call a pro?

If the leak keeps coming back, the damage looks serious, or you’re not sure what type of roofing you have, it’s best to call a professional. DIY may handle small fixes, but complex issues need trained roofing professionals.

6. Can Flat Roof Leaks Be Prevented?

Yes, absolutely. Here’s what you can do –

Schedule annual inspections
Keep gutters and drains clear
Re-seal seams every few years
Apply protective coatings before the rainy season

Takeaway

Ignoring a leaking flat roof can bring various troubles in the future. If you manage a business or industrial building, repairing the leaking roof early can save you from bigger damage and higher repair costs later. You must contact a local and trusted industrial roof services provider for regular inspection, maintenance, and roof repair.

Read More About:

Don’t Wait for a Small Leak to Become a Big Problem – Fix Your Leaking Flat Roof With Foam Experts Co. Today!

We at Foam Experts Co. are your local flat roof experts in Redding. With over 40+ years of experience and a strong reputation for industrial roof services in redding, we deliver reliable solutions that give our clients peace of mind.

We own a trained team and use the most advanced tools and techniques. We don’t just patch leaks, we solve the root problem and extend the life of your roof.

Posted in Foam Expert