Plywood for Shed Roof

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mikehow

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Hi all

We've got a covered seating area in our garden with a lean to shed tacked on the back, the lean to shed roof is on its last legs, water has managed to get in to it and the ply roof is delaminating and slowly bowing in.

With the weather looking good this weekend, I'm planning to crack on with replacing it before we have any serious wind and it carries the remaining roof off in to our neighbours garden :eek:

I've considered various roof coverings, but plan to stick with felt given the roof isn't facing the house (so no aesthetic considerations) also there are several tree branches overhanging it on both sides this is ultimately whats caused the water ingress with branches growing in to the felt on our neighbours side.

Longer term we'll most likely remodel the shed to fit better with our needs once all the other jobs on the house are done - its really a case of patching it up for the next 2-3 years and making it watertight.

From reading the forums I see many people are suggesting OSB3 for shed roofs, but thats mostly with EPDM roofs - is this still the case with felt roofs as well?

At the moment I'm leaning more toward WBP plywood based on the fact the the boards have delaminated rather than turned to mush as the roof has detoriated but happy to listen to any advice from those of you that have roofed a shed.

Thanks in advance for any help.
 
Definitely OSB3, you can get in 8x2 tongue and groove sheets to make handling easier
 
I recovered a shed roof around 8 years ago, plywood, then roofing felt, it its under the canopy of trees, so it doesn't get that much rain, but when it is wet it doesn't dry out quickly either. I've painted over the felt at least once over the years with a mixtures of blackjack or similar, watered down with spirit. I mostly did that because I had the stuff to use up and I figured why not. Point being there is no obvious deteriation of the ply. That's my story, not saying ply is the right choice, but it worked for me
 
Yeah I don't think there is a right answer!

I'm really looking for a quick and cost effetive solution which would point to OSB3.

OSB3 T&G makes sense from an ease of handling perspective, the area is pretty awkward to access.

I'm just mulling over how to install it as OSB3 T&G instructions advise it to be laid horizontally rather than vertically as the existing ply has been laid.

Roof span is 2m with 1 purlin at the moment, so I'd need to install additional support given there would be 5 runs with the T&G to support the staggered boards.

Maybe OSB3 sheet might be the way to go without having to significantly alter the roof, I'm hoping to strip it and patch up tomorrow morning with the help of a mate.
 
I can’t see any reason really why the OSB has to be vertical or horizontal as the t&g are the same. The other consideration is that WBP plywood isn’t anymore it delaminate as quick as look at it when it gets wet. The only plywood that is water resistant nowadays is marine ply and you don’t want to be paying for that! Ian
 
If you went down the osb route I'd want to seal it both sides, and especially the ends, which would obviously be easier at ground level ideally. That might not be possibly if you want to do it tomorrow
 
You could search out some wisa ply which will be wpb. I picked up some Brazil ply for a pagoda which was very good quality for £25 ply dark glue lines even layers and no voids.

Cheers James
 
Thanks all for the feedback on this.

I went with ply and felt for simplicity and speed which given the weather we got worked out well.

The old roof pretty much folded in half when we took it off, so it was just the felt holding things together in the end.

Having stripped everything off we've made some fairly significant improvements and where possible felted over the existing felt to give it even more protection.

Over the weekend we had some pretty significant rain and it all looks dry and water tight, fingers crossed it will last a good few years before I have to come back to this again.
 
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