Noises coming from my GRP Roof
Loud banging or cracking noises can be heard coming from the GRP roof
Possible causes
Thermal expansion and contraction is a normal process that causes your roof to expand with the heat of the day and contract when it starts to cool. You may notice an audible cracking or creaking sound coming from the roof in the morning and evening time.
Louder and more frequent audible banging and cracking however could signal a different issue;
No expansion gap on roof
Not allowing for an expansion gap around the OSB deck resulting in the boards butting up against the wall leaving no room for the roof to expand.
Lack of expansion joints for larger roofs
The polyester resin systems used for GRP Roofing were originally taken from the boat-building industry and are made for strength rather than flexibility. They have been adapted over the years but are still not very flexible this is one of the reasons why our fibreglass roofing kits only go up to 50m², anything over that and you would need to add something called an expansion trim.
If you have a roof over 50m² without expansion joints added and nothing else on the roof to break up the space such as a Velux window or orangery then you will experience thermal expansion and contraction issues.
If you do have a larger roof over 50m² and you haven't started your fibreglass roofing project yet, then we would recommend you think about a different system to a standard GRP like Fibrecoat which is incredibly flexible and doesn't need to use expansion joints.
Delamination
This can be caused by a wide range of problems including applying materials on roof decking not specified for use with the system (ie plywood or chipboard instead of OSB3), damp roof deck at the time of lamination or incorrect catalyst ratios.
Trim issue
Incorrectly fixed and loose GRP roofing trims grinding up against an upstand, flashing or large trims overlapping one another could make a small cracking noise.
Solutions
Unfortunately, loud banging and cracking noises could be many different things and not possible to recommend a quick solution. If you've had the GRP Roof installed by a professional contractor then take the issue up with them, they may come out and investigate further and solve any issues.
If this was a DIY project then you'll need to get up on the roof and troubleshoot any problems yourself. Check for any visual cracks in the trims or roof surface and make sure that the decking is laid following the system guidelines.
Other solutions include changing the colour of the roof to a white or lighter colour using a product like Overcoat which will deflect some of the heat. Green Roofs are another option as they will absorb the heat but you need to ensure your existing roof can carry the additional weight.
Related topics
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