Roof maintenance before rainy season is one of the best ways to identify damage, repair problem areas and prepare your roof coating before prolonged wet weather arrives.
Your roof works hard all year. It is constantly exposed to sunlight, temperature changes, wind, rain, dirt and biological growth. Over time, this exposure can cause roof coatings to fade, chalk, peel or lose adhesion. Cement roof tiles can become increasingly porous or powdery, while exposed metal surfaces can begin to corrode. That is why getting your roof ready for the rainy season involves more than simply applying another coat of paint.
A proper roof maintenance project starts with inspecting the roof, identifying the type and condition of the surface, repairing defects, treating problem areas and then using the correct preparation, waterproofing, primer and coating products. Completing roof maintenance before rainy season also gives you a better opportunity to carry out repairs and allow coatings sufficient time to dry and cure before prolonged wet weather arrives.
Start Your Roof Maintenance Before Rain With a Thorough Inspection
Before buying paint, take a good look at the entire roof system, not only the areas where the colour has faded. Check:
- Roof tiles or metal sheeting
- Ridge tiles and ridge capping
- Flashings
- Overlaps and joints
- Fasteners and fixing points
- Gutters and downpipes
- Previous waterproofing repairs
- Areas around pipes, vents and chimneys
Also inspect the existing coating for:
- Chalking or powdering
- Peeling or flaking
- Cracking
- Fungal or algae growth
- Bare or exposed areas
- Rust or corrosion
- Failed waterproofing around joints and penetrations
A faded roof does not necessarily mean that the coating has failed. Fading can simply be the result of normal weathering. Peeling, flaking, heavy chalking, rust and loss of adhesion, however, require proper preparation before recoating.
Repair the Roof Before You Paint It
Paint is a protective coating, but it cannot repair a damaged roof. Before repainting:
- Replace broken or badly damaged tiles
- Reposition displaced tiles
- Secure loose roof sheets
- Repair or replace defective fasteners
- Repair damaged flashing
- Correct defective overlaps and joints
- Repair damaged areas around roof penetrations
Gutters, valleys, outlets and downpipes should also be cleaned so that rainwater can move freely away from the roof.
What About Water That Ponds on a Flat Roof?
If water regularly remains in one area after rain, investigate why. Possible causes include:
- Blocked outlets
- Poor drainage
- Incorrect roof falls
- Damaged or depressed roof sections
Simply applying another waterproofing product or roof coating over an area of persistent ponding does not correct the underlying drainage problem.
Know What Your Roof Is Made From
One of the most important parts of a roof repaint is identifying the surface correctly. A cement tile roof should not automatically be prepared in exactly the same way as a galvanised metal roof. Different roof surfaces have different preparation and priming requirements. Universal Paints offers a complete roof coating system that can include products such as:
- Acrylic Sealer
- Bonding Liquid
- Galvanised Primer
- Red Oxide Quick-Dry Primer
- Zinc Cleaner
- Flexi Rubber
- Uniproof
- Roof Acrylic
The products required will depend on the roof surface and its condition.
Preparing Cement Roof Tiles and Fibre Cement
Older cementitious roof surfaces can become porous, chalky or powdery after years of weather exposure. Before coating, the surface needs to be clean, dry, sound and free from contaminants. Remove:
- Dust
- Loose material
- Chalking
- Loose or flaking paint
- Fungal growth
- Algae
- Dirt and contamination
If the existing coating is loose or unstable, it needs to be removed rather than simply painted over. Depending on the condition of the roof, Acrylic Sealer or Bonding Liquid can be used as the base coat before Roof Acrylic.
When Would Bonding Liquid Be Useful?
Bonding Liquid is particularly useful where an older surface has become powdery, friable or very porous. It penetrates the surface and helps stabilise it, creating a stronger base for the coating system. This is important because applying good-quality roof paint over an unstable surface will not make the surface underneath it stronger.
Treat Fungal and Algae Growth Before Painting
Those black, green or dirty-looking areas on an older roof should not simply be painted over.
- Where fungal or algae growth is present, treat the affected area with Fungal Wash before continuing.
- Apply the product to the affected surface and allow it to soak in. After approximately 12 hours, scrub the area thoroughly with plenty of clean water.
- Allow the roof to dry completely before applying the next product.
- If contamination is still visible, repeat the treatment.
Painting over biological growth can interfere with adhesion and trap contamination beneath the new coating.
Metal and Galvanised Roofs Need Different Preparation
Metal roofs need particular attention because both contamination and corrosion can affect how well the new coating adheres.
New or Uncoated Galvanised Steel
New galvanised steel can have manufacturing oils, grease and other contamination on the surface. Zinc Cleaner is designed to clean and degrease galvanised steel and rust-free mild steel before coating.
- Apply it with a cloth, mop or brush, scrub the surface with a bristle brush or broom and rinse thoroughly with clean water.
- The aim is to achieve a water-break-free surface. In simple terms, when clean water is applied, it should spread evenly across the metal rather than pulling away into droplets because grease or oil remains on the surface.
- Repeat the cleaning process if necessary and allow the metal to dry thoroughly.
- Once clean and dry, the galvanised steel can be primed with Galvanised Primer. Allow approximately 4–6 hours drying time before applying the next coating.
What About an Older Painted Metal Roof?
Previously painted metal needs to be clean, dry and sound before recoating.
- Remove loose and flaking paint and sand the remaining coating.
- If rust is present, prepare the affected areas back to bright metal. This means removing the rust until clean, sound metal is exposed.
- Depending on the metal surface, the prepared area can then be spot primed with Galvanised Primer or Red Oxide Metal Primer.
- Allow approximately 4–6 hours drying time before continuing with the coating system.
The existing paint also needs to be well adhered. Remember that your new coating is ultimately relying on the old coating underneath it to remain attached to the roof.
Include Waterproofing in Your Roof Maintenance Before Rain
Not every part of a roof simply needs roof paint. Areas around:
- Flashings
- Joints
- Laps
- Roof penetrations
- Parapets
- Previous repairs
These areas may require additional waterproofing before the final roof coating is applied. Universal Paints offers different waterproofing options depending on the area and problem:
Flexi Rubber
Flexi Rubber is a flexible waterproofing coating that can form part of the waterproofing system in areas requiring additional protection. It is applied in two coats, allowing approximately 6–8 hours drying time between coats. Its flexibility makes it particularly useful where minor movement or hairline cracking needs to be accommodated.
Uniproof
Uniproof is a water-based acrylic waterproofing compound with reinforcing fibres incorporated into the product. The fibres help reinforce the waterproofing layer without requiring a separate reinforcing membrane. The system uses three coats, allowing approximately 6–8 hours drying time between coats, followed by two coats of a suitable Universal Paints topcoat.
Waterproofing products should be used to complement a sound roof system. Broken tiles, defective flashings, loose roof sheets and drainage problems should still be repaired first.
Applying Roof Acrylic
Once the roof has been inspected, repaired, cleaned, treated and correctly primed or sealed, the roof coating can be applied. Roof Acrylic is a water-based pure acrylic roof coating suitable for surfaces including:
- Cement roof tiles
- Fibre cement
- Suitable roof sheeting
- Correctly primed metal surfaces
Apply two full coats, allowing approximately 4–6 hours drying time between coats. When applying by brush or roller, Roof Acrylic should not be thinned. For spray application, the first coat may be thinned by approximately 10% where required.
Don’t Stretch the Paint Too Far
Correct coverage is important. Trying to make a bucket cover substantially more roof area by spreading the coating too thinly can reduce the protection provided by the finished coating system. Actual coverage will also vary according to:
- The condition of the roof
- How porous the surface is
- The profile and texture of the roof
- The application method
- The applicator’s technique
An older, porous or heavily profiled roof may therefore use more paint than a smoother surface. The aim should be two even, full coats, rather than stretching the product to achieve maximum square metres from every litre.
Choose the Right Weather Window
Timing is particularly important when carrying out roof maintenance before rainy season.. Try to plan the project during a period of stable, dry weather. Avoid painting when:
- Rain is expected
- Mist or fog is likely
- Condensation may develop
- The roof is still damp
- Conditions are particularly cold or humid
Cold, damp and humid conditions can slow drying and curing. Also remember that dry to the touch does not mean fully cured. A coating can feel dry on the surface while it is still developing its full strength underneath. Painted surfaces should not be washed or deliberately wetted for seven days after painting, so allow enough time for the coating system to cure properly.
Common Reasons Roof Paint Fails Too Soon
When roof coatings fail prematurely, the problem is often related to preparation rather than simply the final coat of paint. Common causes include:
- Painting over dust or dirt
- Painting over chalking
- Painting over fungal or algae growth
- Leaving loose paint underneath the new coating
- Painting over damp surfaces
- Failing to degrease new galvanised steel
- Painting over rust
- Using the wrong primer
- Not repairing the roof first
- Applying the coating too thinly
- Not allowing enough drying time between coats
- Painting when rain or condensation is expected
Taking a little more time with preparation can make a significant difference to the final result.
Treat Your Roof as a Complete System
Effective roof maintenance before rainy season is not simply: Clean → Paint
A better approach is: Inspect → Repair → Clean → Treat → Prepare → Prime or seal → Waterproof where required → Apply the correct roof coating → Allow sufficient drying and curing time.
Most importantly, match the products to the roof you actually have. A weathered cement tile roof, fibre-cement roof and galvanised metal roof do not necessarily need the same preparation or primer. Taking the time to inspect and prepare your roof correctly before the rainy season helps reduce the risk of coating failure and gives the complete roof coating system the best opportunity to perform as intended.
Visit your nearest Universal Paints Direct Outlet for help identifying your roof surface and choosing the correct preparation products, primers, waterproofing products and roof coating system for your home.
