Why is my flat roof leaking?

What usually causes a flat roof to leak?

A flat roof is not completely flat. It has a slight slope that moves water to an outlet. When water stays on the roof instead of draining, it finds any weak point. Strong Highveld sun ages the waterproof layer, and heavy summer storms then test it.

• A cracked, split or blistered waterproof layer, usually from age and sun.
• Joints and edges, where the roof meets a wall, a parapet or an upstand.
• Water that stays on the roof (ponding) because of low spots or a blocked outlet.
• Blocked or damaged box gutters and roof outlets.
• Gaps around things that go through the roof, such as skylights, vents, pipes and solar panel mounts.
• Damage from people walking on the roof, from tools, or from hail.

What can I check safely?

Stay on the ground or inside the house. Do not walk on a wet roof.

• Note when the stain appears. A stain that shows up only after rain points to the roof. A stain that appears when it has not rained may be a pipe.
• Look at where the stain is. A stain under a wall edge, a skylight or a vent points to a joint or seal there.
• From a safe place, such as an upstairs window or the ground, look for water still sitting on the roof a day after rain.
• Look for leaves and dirt over roof outlets and in box gutters you can see from the ground.
• Take dated photos of the ceiling stain and the roof. They help any contractor price the job.

What should I do while I wait for a repair?

• Move furniture and put a bucket under the drip.
• If water is near a light fitting or plug, switch that circuit off at the distribution board and do not use it.
• If the ceiling is bulging with water, keep people clear of the area below it.

When should I call someone?

Call a professional when:

• The stain comes back after every rain, or is getting bigger.
• The ceiling is sagging or bulging.
• Water is getting near electrics.
• The roof surface is visibly split, bubbled or lifting.
• Water stands on the roof more than a day after rain.
• The roof is high or hard to reach. Do not climb it yourself.
• Your roof has old cement sheets that may contain asbestos. Do not scrub, drill or break them.

How does Oaks fix a leaking flat roof?

Oaks' price list covers the jobs a flat roof leak usually needs: a leak repair and reseal, waterproofing a section of flat roof, waterproofing a full flat roof (torch-on), sealing cracks and joints, and waterproofing box gutters. Which one fits depends on where the water is coming in and how far the damage runs. Oaks confirms that in the quote.

1. Send photos of the leak and the roof, and your suburb, on WhatsApp to 081 372 4079 or through the Instant Price form.
2. Oaks sends a fixed price in a quote, valid for 14 days.
3. Oaks books the job within 7 days.
4. When the job is finished you get a photo report.

Waterproofing comes with a 5-year warranty and every Oaks job has a workmanship guarantee. A 50% deposit is paid before work starts and the balance when the job is done.

What does a flat roof leak repair cost?

A price marked 'from' is where that kind of job starts. These are northern-suburbs rates. For worked examples and what changes the price, read the waterproofing cost guide.