roof

How to Repair a Leaky Flat Roof

Introduction

The most important part of fixing a leaky roof is finding the source of the leak. You will need to look over the entire roof very closely and carefully. Be especially thorough because it would be a shame if you had to go through the entire process again if you didn’t repair every potential leak source the first time. Once you identify the problem areas, you will be ready to make the necessary repairs. Make sure you are not afraid of heights before attempting this project because you will be on top of your roof.

Difficulty: Difficult

Things You'll Need:

- Binoculars

- Weighted markers

- Flashlight

- Roofing cement

- Trowel

- Heavy-duty razor or carbide blade

- Patching fabric

- Rag

Instructions

Step 1

Look very thoroughly at your entire roof with binoculars. Check for tears, cracks, rotting areas, missing sheathing, and any other potential issue. Also make sure that there are no breaks in material such as no spaces between the brick of the chimney and the roof sheathing.

Step 2

Go on the roof and put a weighted object by each problem spot that you found. Walk along the roof and inspect every area up close. Mark any other problem areas that you find with weighted objects.

Step 3

Go into your attic. Check for any potential water trails with a flashlight. If you find any, follow them up to where they hit the ceiling and push a nail at that point so you can easily find the problem spot when you get back onto the roof.

Step 4

Repair cracks in the sheathing. Clean the crack by scraping away any dirt. Cover the crack with roofing cement and use a trowel to cover the crack completely. Push a piece of roof patching fabric deep into the cement. Repeat Step 4 for all cracks.

Step 5

Repair bubbles in the sheathing. Use a heavy-duty razor or a carbide blade to cut an “X” into the bubble. Pull up the sides of the cut sheathing. Empty the area underneath the bubble of debris and soak up excess moisture with a rag. Let the bubble dry in the sun for a few hours. After that, put some cement under the sides of the sheathing and flatten the area. Apply a layer of cement and cover it with patching fabric and then another layer of each. Finish with a last layer of cement. Spread the cement into the sheathing. This will allow for drainage. Repeat Step 5 for all bubbles.

Step 6

Repair breaks in materials such chimney bricks and roof sheathing. Clean the area and remove old pieces of cement that may become irksome. Work a layer of cement between the roof feature and the sheathing. Spread the cement into the sheathing. This will allow for drainage. Repeat Step 6 for all breaks.

Tip

Rub penetrating oil like WD40 onto your hands to remove roofing cement.

Warning

Be thorough when searching for water trails because they can be tricky and curvy.