The key to a long-lasting flat roof is regular maintenance, and one part of this is regular cleaning. This helps prevent damage and the buildup of elements that can harm your roof, such as pooling water and moss.
But what does cleaning a flat roof entail? In this blog, we’ll guide you through the most efficient way to clean your flat roof.
Why should you clean a flat roof?
Alongside roof inspections twice a year to help identify minor issues, cleaning a flat roof is also a great way to keep your flat roof looking healthy.
Cleaning and other regular maintenance can help prevent water damage from ponding, stop mold from growing, help to increase the life expectancy, and make the overall aesthetic of your property look better!
Safety Tips
It’s important to stay safe when cleaning your flat roof. We recommend always wearing non-slip shoes when on the roof surface, as well as gloves and a harness. It’s also important to always have somebody with you.
If you’re unsure if you can clean your roof safely, contact a roof cleaning company to help.
What you’ll need:
- Soft-bristled brush or broom – to remove dirt, leaves, and debris without damaging the roof surface
- Plastic shovel or scoop – useful for clearing heavy moss or build-up (avoid metal tools)
- Bucket – for water or cleaning solution
- Low-pressure hose – to gently rinse the roof surface
- Mild detergent or specialist flat roof cleaner – safe for felt, EPDM, or GRP roofs
- Moss and algae treatment (roof-safe) – to kill organic growth and help prevent regrowth
Step-by-Step Guide to Cleaning a Flat Roof
1. Choose the Right Time and Check Conditions
The safest time to carry out flat roof cleaning is during dry weather, so this will ideally be in the spring. During extreme weather conditions, like hot weather and winter, you can do more damage, and the surface can be icy, increasing the risk of slips.
2. Inspect the Roof Before Cleaning
Before cleaning, inspect the roof surface for cracks, stains, water damage, loose materials, and the growth of moss or mould.
Early inspection helps identify whether cleaning alone is enough or if a roofing professional may be needed for repair.
3. Remove Loose Debris
The first place to start when you get to cleaning is removing loose debris, like leaves, twigs, dirt, and moss. Do this using a soft brush, a leaf blower, and a bucket to collect debris into.
Be careful around drains and gutters, and avoid using sharp objects, which can damage EPDM roofing and other flat roof materials.
Overhanging branches and nearby trees often contribute to debris build-up, so trimming them can help reduce future issues.
4. Clear Gutters and Drainage Systems
Ensuring proper drainage is one of the most important parts of cleaning a flat roof. Blocked drainage systems, gutters, or drains can lead to standing water, which increases the risk of leaks and structural damage.
Remove debris by hand or with a soft brush and make sure water can flow freely away from the roof surface.
5. Prepare a Safe Cleaning Solution
For cleaning a flat roof, especially an EPDM rubber roof, use a mild detergent mixed with warm water. Avoid harsh chemicals and petroleum solvents: These can damage rubber roofing, reduce UV resistance, and shorten the roof’s life expectancy.
6. Gently Scrub the Roof Surface
Using a soft brush, gently scrub the surface to remove stains and mold. Work in small sections and avoid applying too much pressure.
Never use a pressure washer, as high-pressure water can damage EPDM rubber, loosen seams, and lead to further damage or leaks.
7. Rinse with a Garden Hose
Once the roof surface is clean, rinse thoroughly using a garden hose. Make sure all cleaning solutions, dirt, and debris are washed away and directed towards the drains.
8. Final Inspection
After rinsing, inspect the roof again to ensure there is no debris, the drainage systems are clear, and the flat roof is in good condition. You can check for any signs of damage that may have been hidden before cleaning.
