To repair your property's GRP fibreglass flat roof, start by evaluating the roof's condition, checking for cracks, pinholes, discolouration, and delamination. Verify that the sub-deck is sound and well-secured, and confirm the correct timber boarding is used.
Prepare the surface by cleaning it with a mild detergent and water, scraping off old coatings and sealants, and inspecting and preparing the edges. Use a putty knife or scraper for this, taking care not to damage the GRP surface.
Now that you're ready to tackle the repairs, let's walk you through the detailed process of fixing your roof.
Key Points
- Inspect the roof for cracks, delamination, and damage, considering age, and evaluate if repair or replacement is necessary.
- Prepare the surface by cleaning with a mild detergent, removing old coatings, and inspecting edges for a successful fix.
- Use a GRP repair kit containing restoration coating, chopped strand matting, catalyst, and a laminating brush for small-scale damage.
- Apply the kit by mixing the catalyst, adding a primer if necessary, and applying a film thickness of 500-600 microns for top performance.
- Perform Electronic Leak Detection (ELD) for non-invasive, mm-accurate testing, except with high carbon content roofs, in dry or wet conditions.
Assessing the Roof's Condition
Evaluating the condition of a GRP fibreglass flat roof is a crucial step in determining if repairs are needed, and if so, what kind of work should be done.
When inspecting the roof's surface, you'll need to check for cracks, which can be caused by poor installation, thermal movement, or incorrect timber boarding. Look for pinholes, discolouration, bubbling, blistering, or delamination, which can lead to leaks and water ingress.
Check for alligatoring of the GRP top coat, a sign of the roof shriveling up.
Next, you'll need to assess the structural integrity of the roof.
Verify the sub-deck is sound and well secured, and that the correct timber boarding is used. Check for swollen timber boards and verify that the perimeter edges and timber boards have adequate movement allowance to prevent thermal movement cracks.
The sound surface preparation is essential for applying the laminate to prevent water ingress and ensure a reliable flat roofing solution, with a 600g/m2 glass fibre matting being used in the process.
Confirm that the roof has the required insulation and vapour control layer to prevent moisture-related issues.
Identifying Weak Areas and Damage
When inspecting your GRP fibreglass flat roof, it's crucial to identify weak areas and damage to guarantee you catch potential issues before they escalate into costly problems.
Look for cracks, the most common defect in GRP fibreglass roofs, which can result from poor installation, movement, or exposure to harsh chemicals.
Delamination, where layers separate due to temperature or moisture changes, is another issue to watch for, often occurring at joints and causing blistering and bubbling.
Also, inspect for pinholes, tiny holes on the surface, which can lead to water ingress and leaks. Bubbling and blistering can occur due to poor installation or adhesion failure.
Check for sagging areas where the roof levels change, allowing water to pool, and discolouration from UV exposure or persistent water pooling.
Regularly inspect seams and joints for signs of leakage.
Check gutters and downspouts for blockages and noise issues.
Alligatoring, where the roof loses elasticity, is another sign to look out for.
When inspecting the roof, make sure to clean the fibreglass roof area thoroughly with a pressure washer, taking care not to damage the fibreglass, to get a clear view of any potential issues.
Preparing the Roof for Repairs
Before you start repairing your GRP fibreglass flat roof, you'll need to prepare the surface to guarantee a successful and long-lasting fix.
This involves several steps, including cleaning the roof surface, removing old coatings and sealants, inspecting and preparing the edges, and setting up safety and access.
Cleaning is an essential part of the preparation process. Use a mild detergent and water to clean the surface, ensuring no harmful chemicals are used.
A soft-bristled brush can help remove stubborn dirt, and a thorough rinse will prevent any residue.
When it comes to preparation, don't forget these key steps:
- Set up stable access via ladders or scaffolding and use appropriate safety gear, including harnesses, gloves, and safety glasses.
- Use a putty knife or a scraper to scrape off old coatings and sealants, taking care not to damage the GRP surface.
- Trim any damaged or loose edges using a GRP-specific cutter and clean them thoroughly.
- Lay down protective sheets or mats around the work area to prevent damage to surrounding surfaces.
Evaluating Repair or Replacement
As you assess your GRP fibreglass flat roof, you'll frequently need to weigh the pros and cons of repair versus replacement.
The age of your roof plays a significant role in this decision, as those over 20 years old may be nearing the end of their lifespan. Typically, GRP roofs last between 20 to 25 years, and older roofs may have multiple areas of damage, making replacement more practical.
Consider the extent of the damage and whether it exceeds 50% of the roof area. If so, replacement is likely the better option, as extensive damage can compromise the structural integrity of the roof.
Additionally, inspect the roof's underlying structure and look for signs of widespread delamination or cracking, which may indicate a need for replacement.
Evaluate the cost of materials and labor for extensive repairs versus replacement, and consider the long-term savings from a new, energy-efficient roof. In some cases, a GRP Restoration Coating can restore the roof for another 10-15 years.
Weigh the inconvenience and downtime of replacement versus repair, and factor in the guarantees and warranties offered with new installations.
Repairing Small Scale Damage
Your GRP fibreglass flat roof's damage may be limited to small, isolated areas, making targeted repairs a viable and cost-effective option.
To begin, inspect the roof thoroughly to determine the extent of the damage. Clean the affected area using a pressure washer or soap and water to remove debris and dirt, then verify the surface is completely dry before starting repairs.
For small-scale damage, use the following techniques to achieve a successful repair:
- Apply a resin topcoat to repair pinholes and minor surface cracks, making sure it's fully covered.
- Use a fibreglass matting and resin combination for slightly larger cracks, and allow the resin to dry completely before testing for leaks.
- Utilize a Fibreglass Roof Hole Repair Kit for small holes and gaps, applying a mouldable UV-cured patch such as Speedpatch.
- Apply a topcoat of protective sealant over the repaired area to guarantee waterproofing, using a sealant compatible with the GRP material and following the manufacturer's instructions.
GRP roofing systems have a BBA guarantee of up to 40 years, providing homeowners with long-term reassurance that their roof will remain secure and watertight throughout the repair process.
Performing Extensive Repairs
When the damage to your GRP fibreglass flat roof is more widespread, it's often necessary to undertake a more exhaustive repair approach.
This involves evaluating the damage thoroughly to determine the extent of the issue and identifying weak areas, cracks, and potential causes of further damage. You'll also need to check for common defects such as cracking, delamination, and blistering. Documenting the condition of the roof will help you plan the repair strategy.
To prepare the area, clean it thoroughly using a pressure washer, avoiding damage to the fibreglass.
Allow the surface to dry completely before beginning repairs. Remove any damaged sections of fibreglass back to the base material and apply a coat of primer to the affected area. If you're working with an OSB3 deck, verify it's completely dry and clean.
Next, mix fibreglass resin according to the manufacturer's instructions and apply it over the primed area using a brush or roller.
Lay a layer of fibreglass matting over the resin and allow it to dry. Consolidate the resin and matting using a paddle roller to eliminate bubbles.
Using GRP Fibreglass Kits
Effectiveness is key when it comes to repairing a GRP fibreglass flat roof, and using GRP fibreglass repair kits can be a reliable option.
These kits provide you with the necessary materials to complete the repair, including GRP Restoration Coating, chopped strand matting, catalyst, laminating brush, and a clear graduated mixing cup.
Before applying the kit, you'll need to prepare the surface by sanding it with 40-grade sandpaper, wiping it clean with acetone, and removing any contaminants or old coatings.
- Sand the surface with 40-grade sandpaper to guarantee a smooth finish.
- Wipe the surface clean with acetone to remove any dust or debris.
- Apply the GRP Topcoat out of direct sunlight and heat for peak results.
- Build up to a film thickness of 500 - 600 microns for top performance.
When applying the kit, make sure to add the maximum 2% ResiRoof Catalyst by volume and mix well by hand.
Apply approximately 0.6kg per m2 using a short pile roller for main areas and a brush for edges and corners.
With a coverage of 8.3m2 per 5kg container, you can easily complete your repair and enjoy a maintenance-free surface.
Repairing With Resin and Matting
Repairing a GRP fibreglass flat roof with resin and matting requires meticulous attention to detail and a step-by-step approach to guarantee a successful outcome.
You'll start by preparing the area for repair. Clean the surface thoroughly using a pressure washer or soap and water, and allow it to dry completely.
Identify and mark all damaged areas, including cracks, holes, and delamination, and remove any debris or obstructions.
Next, apply a coat of grp primer to the affected area using a brush or roller, ensuring proper adhesion.
Mix the fibreglass resin according to the manufacturer's instructions and apply it over the primed area.
Once the resin is dry, lay a layer of fibreglass matting over it, pressing firmly into place.
Apply additional resin over the matting, ensuring it's fully saturated, and allow it to dry completely.
Sand the surface with medium-grit sandpaper to smooth and even it out.
Testing for Leaks and Damage
Before you can confidently declare your GRP fibreglass flat roof repair a success, you need to test for leaks and damage to verify the integrity of the roof.
This involves using various methods to detect even the smallest defects in the roof's surface. One of the most effective methods is Electronic Leak Detection (ELD), which is a non-invasive method that identifies defects with mm accuracy.
You can use the following methods to test for leaks and damage:
- Electronic Leak Detection (ELD): This method can be performed in dry or wet conditions and is compatible with most flat roofs, except those with high carbon content like EPDM.
- Wet Testing Method: This method involves surrounding the area with a trace wire and using electrodes and a pulse generator to send an electrical pulse through the wet roof surface.
- Dry Testing Method: This method uses high voltage to identify faults when the roof surface is completely dry and is a far quicker method compared to wet testing.
- Thermal Imaging: This method uses thermography to identify wet areas through temperature discrepancies, shown in darker colors.
Ongoing Roof Maintenance
To keep your GRP fibreglass flat roof in top condition, you'll want to commit to regular maintenance, which not only guarantees the roof's longevity but also saves you from costly repairs down the line.
Start by cleaning your roof at least once a year using a long-handled mop, bucket, or garden hose. For tougher debris, use a pressure washer, but avoid hot steam to prevent damage.
Clear gutters and drainage points to guarantee water flows freely.
Regular visual inspections are also vital.
Check your roof at least twice a year and after severe weather conditions. Look for signs of damage, wear, cracks, discolouration, and changes in levels or movement.
Check seams and joints for leakage and note any effects of seasonal changes.
Additionally, prevent common issues by trimming trees near your property and checking drains and gutters regularly.
Avoid standing water by verifying your roof has a mild incline.
Monitor for plant growth and debris buildup, and consider applying protective coatings to maintain the roof's insulating and protective properties.
Rounding Up
You've now completed the ultimate guide to repairing a GRP fibreglass flat roof . With the steps outlined, you can assess, prepare, and repair your roof effectively. Remember to test for leaks and damage after completing the repairs. Ongoing maintenance is vital to extend the life of your roof. By following these steps and staying on top of maintenance, you'll be able to enjoy a watertight and durable GRP fibreglass flat roof for years to come.
