Roofing Services Scotland & Cumbria
We are well known throughout Scotland & Cumbria for our quality roofing and great service.
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Flat Roof Decking OSB-3 vs Plywood | Delamination

OSB board or Roofing Plywood

Don’t use ply-wood for a flat roof that’s going to be fibreglass – even marine ply, Cure-it, GRP or Topseal. It will not guarantee a roof if you’ve used Plywood – it must be OSB-3.OSB plywood

Problems installing fibreglass on the wrong decking boards:

Fibreglass should always be installed on OSB-3 sterling board preferably with tongue and groove edges,

Boards with tongue & groove (T&G) edges comes in 2ft x 8ft or without T&G in 4ft x 8ft which can be a bit difficult to handle especially if you’re working two to three story’s high and need to lift the boards up to roof height

norbord products sterling-osb/sterling OSB-tongue-and-groove

OSB3 roof decking for a GRP fibreglass flat roof

OSB board or Marine Plywood for a flat roof 

The 2400mm x 600mm or 2ft x 8ft boards are the best and the most popular,  (T&G) on all sides and easy to handle,

The perfect boards for fibreglass resin to bond to, with no surface preparation needed there also more water resistant then plywood.

  • Plywood will need to be sanded before the GRP will bond
  • OSB with T&G profile stops the edges of the boards dishing or warping whilst the fibreglass cures
  • Plywood needs to be finished on the joist/beam or noggin. OSB3 doesn’t its supported by the T&G this helps with the waste off cuts too…
  • All but joints with plywood will need additional CSM (chopped strand matting) bandage

Roofing plywood

OSB3 is by far the best choice for a fibreglass flat roof or balcony

Plywood does de-laminate especially if there’s any moisture ingress like condensation from underneath this will cause the boards to de-laminate from the fibreglass check out our video on this problem,

Sam Verry
Sam Verry
16:16 31 Aug 19
We needed some new guttering on an old property we recently purchased as the existing guttering was causing us some damp issues, Abbey roofing gave us a reasonable quote and started the work within a few days of us accepting the quote. The work was completed professionally and to a very high standard. I have since had abbey roofing back to carry out some work on the roof and again I am really pleased with the work. Would highly recommend these guys.
Lee Preston
Lee Preston
11:26 12 May 19
Looks great, top workmanship, efficiently done and in a short time!
08:16 25 Apr 18
Prompt response, arrived to look at job when he said, gave a thorough account of what needed done, we agreed a price. The next fine day he arrived early with another worker and job done before end of day. Prompt, efficient, professional and reliable. My old cast iron guttering now looks like new and doesn't leak....hurray! Thanks James.
james thomas
james thomas
17:48 08 Mar 18
I have used James and his roof firm twice now and have had fantastic service each time. He is very quick to provide advice and all his work is timely and of a great standard . I would happily recommend and will be using him again in future .
arron weaver
arron weaver
15:01 28 Oct 16
Great price, no hidden costs, professional and friendly service, the results were simply stunning. would recommend to anyone. Thank you to all the team. Great work!
Michael Seidelmann
Michael Seidelmann
14:56 14 Oct 16
Jim and his team have been carrying out several jobs at our cottage, including re-roofing and guttering. We are delighted with both the level of service and the quality of work. Happy to recommend.
Ed Hagerty
Ed Hagerty
19:31 13 Oct 16
We’ve been restoring a house in Cumbria and over the years we’ve had tradespeople from across the spectrum. I can comfortably say that Jim and his team are in the very top of the list in terms of quality, price and service. They did a flat roof for us, some lead work and a variety of other external work, all of the highest quality. If Jim provides the service, you need look nowhere else. We’d trust him with any job, large or small.
Katherine Massey
Katherine Massey
14:11 26 Mar 15
Jim and Chris recently carried out outstanding work to our fibreglass roof on a listed building. We were delighted with the standard of workmanship, service, communication and the 25 year guarantee. The work was carried out in a timely and professional manner and was also reasonable in terms of cost. We were lucky to get some dry weather and guys that really know what they are doing. Thanks Jim, much appreciated! I will recommend you to family, friends and anyone I come across!
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