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How do I laminate a Fibreglass Roof?

Before starting laminating, ensure that the weather conditions will be acceptable. Do not lay the roof if rain is forecasted. Temperatures should be at least 15°C to allow the resin to cure. If the temperature is too hot (over 25°C) the resin will cure too quickly.

  • Sweep down the roof to remove any debris. We start by bandaging the joints, trims and corners.
  • If you are not using T&G, the joints in the decking should be taped up using masking or any type of tape. This is just to prevent the resin from dripping between the boards. We used T&G so there was no need for this here but we have shown it for demonstration purposes.
    • Glass bandage should be used to strengthen all the joints on the decking and the trims. Measure out the glass bandage roll and cut or tear to length. It is a good idea to lay the bandage out on the roof before rolling it up and placing beside the joints ready to use.
    • Weigh out your resin. Mix 2% catalyst in with the resin. For this, we mixed 0.5kg of resin at a time.
    • Wet out the joint with resin using a paint brush or roller.
    • Roll out the glass tape over the resin.
    • Wet out the glass with more resin, until it is fully saturated.
    • Consolidate with a paddle roller. Ensure there are no pinholes and the mat turns transparent.
    • This should be repeated with the joints in the trims. Wet out the joints with the resin using a paint brush again.
    • The edges of the fibreglass can be frayed or feathered, by pulling at the edges to make the seam less visible on the front trim. This will help with the final appearance.
    • Wet out the glass with a paint brush as before.
    • Consolidate with a paddle roller
    • To fibreglass, the ends of the raised edge roofing trims, cut out a square of fibreglass that covers the area +50mm onto the trim. Cut relief cuts around the top of the fibreglass so that it can be folded smoothly over the top of the trim.
    • Again, wet the glass mat out with a paint brush and consolidate with a paddle roller.
    • The same method should be used on the internal corners.
    • Measure the fibreglass mat to size and cut using a Stanley knife. When joining two pieces of the mat, the edges should overlap by 50mm.
    • To create a less visible seam between the two mats, the edges are frayed by lightly pulling.
    • Mix the resin and catalyst. Place the bucket on the weighing scales and reset the scales.
    • We recommend mixing 2kg at a time. This will be enough to cover 1m2 at room temperature.
    • Add the catalyst to the resin. The recommended rate for adding catalyst is 2% at room temperature. Mix the resin and catalyst thoroughly for at least one minute, It will change colour slightly as the catalyst is mixed through.
    • Use a roller to wet out the OSB board
    • Lay the fibreglass out onto the wet resin.
    • Apply more resin to the glass mat until the glass mat is fully wet out. Consolidate the resin and glass with a paddle roller. Ensure that there are no pin holes. The glass will start to appear transparent at this stage.
    • It is a good idea when working on a larger roof to have one person putting on the resin and the mat and a second person following.
    • Once cured, lightly sand the area with a coarse sandpaper. The roof is now ready for Topcoat.
Published in: Fibreglass Roofing