Replacing chipboard on flat roof

[robgraham]

This was put onto a log shed roof when it was built some 20 years ago

- it was the material to use then as it was bitumen coated, but age and weather has taken it's toll and I will be lucky if it lasts out the winter - I'm keeping my fingers crossed it will keep the logs dry till the warmth and dryness of spring (hollow laughter) when at least the days will be long enough to get the replacement roof on in a day. The neighbouring cycle shed roof came off in the Boxing Day gale of 14 years ago and that was not nice replacing that under pressure and working till 8 pm on a December night.

Anyway, less of the waffle - what substrate material for the felt is in favour now? The roof is some 1.75m deep by 3m long with a shallow fall. My instinct is sterling board. At 70, I could use chipboard again !!!!

Rob

[Cash]

Rob,

Would you consider replacing with colour steel roof sheets such as

have the advantage of being ideal for such a situation, the roof can be replaced in less than a day and will easily span 3 metres without additional supports.

If not, the you should replace it with 22mm WBP external grade plywood - and refelt the roof.

Cash

[robgraham]

I thought of plywood, but a) 22mm is way to heavy on the pocket for a roof of this application and size and b) it's horrible stuff to nail into from past experience.

I realised after I'd posted that I'd used Onduline on my workshop roof and found it so easy to apply and overall cheaper than proper felting, leaving aside the effort of doing a good roof felting job. If nothing else comes up I'll probably go that way - may be necessary to add a frame timber of two but all that will be easy.

Thanks for your reply.

Rob

[NT]

Chipboard does fail faster once it gets wet, but ply and osb dont extend the life by much, and chip is still a usable option, and of course cheap as chip.

NT

[PeterC]

IME OSB should see you out (and could then be used for your coffin!). I've had OSB unprotected outside for about 20 years. It had spent 2 or 3 years covering a windo next door then, about 20 years ago, I used some of it in a very testing way: in shade, horizontal and on to of a water butt. It's slimy on top and 'splintery' underneath but still sound.

The correct grade is needed - I don't know what it is that I used.

[robgraham]

How did you know ?

Rob

[PeterC]

Oh, sorry, couldn't find the symbol for 'muffled voice' ;-)