plywood 17gbp: good price?

[Fred]

Hello,

I have got to replace the rotten chipboard on my flat roof. I keep meaning to do it before summer ends! Every now and again I phone around timber merchants to see how much wbp plywood is (4' x 8' x

18mm, excuse the mixed units). Over the months the price seems to have gone up and up but one firm who specialise in "roof supplies" say they can supply at 17gbp + vat. That seems to good to be true. Should I be suspicious or should I buy, buy, buy?

Another timber yard recommended osb3. I know that can be used for flat roofs but is plywood better?

TIA

[Jim K]

I was buying "best" aka "Far Eastern" 18mm ply a few months ago by the sheet for =A322.50 +VAT

Google for info on the different grades of ply and ask yr supplier which they have and at what prices - take from there.

Cheers Jim K

[Andy Dingley]

OSB3 is better, but make sure it is (read what's printed on the edge) as most only sell OSB2, which isn't really up to the job.

OSB isn't as good as plywood for spanning wide gaps unsupported, and it's often heavier for equivalent strength, but otherwise it does last OK under a roof.

[pete]

Does that price include delivery? It's heavy old stuff, about 100lbs (since we're mixing units:-) per

1 inch of thickness (so 18mm is about 765lbs per sheet). It sounds like you'd be looking for a fair few boards.

[Jim K]

erm...no...care to check that again?!?!?!

I can carry an 18mm sheet.....and I ain't in the olympics!

Jim K

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Fred saying something like:

Blimey, that's as cheap as shuttering ply - buy buy buy, if it's genuine decent stuff.

[Tabby]

I bought WBP from a well known supplier, only to have it delaminate after a single rain while it was waiting to go up. Had WBP printed on the boards too.

NT

[pete]

Figner trubble.

18mm ~ 3/4 inches. 3/4 * 100 = 75lbs.

[Rick Hughes]

Boll**ks

I can pick up an 18mm sheet and carry it (if balance is right) ,.... no way I could carry 765Lb, you have this wrong.

In fact I would estimate as around 1/10th of that, maybe you have decimal point in wrong place.

[Rick Hughes]

Nothing wrong with correct grade OSB for flat roof, as long as c/s for joists are suitable.

It is impossible to know if 17gbp is a good price unless you know the grade. Plywood has numerous grades - take a look at

it has waterproof ratings (actually the adhesive) such as Marine Ply, WBP etc.

A decent 18mm exterior B-C grade sheet should be around £22 - £24 +vat

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Tabby saying something like:

I've come across some bogus stuff too. Luckily, I saw a couple of sheets had delaminated before I bought any, so went elsewhere. The stockist was a reputable one, so I suspect they'd been conned along the line.

[Tabby]

Ditto, it was a major supplier. Its their job to check what they get before accepting the goods and selling them on, clearly theyre failing to.

NT

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Tabby saying something like:

Indeed so. Similarly, there was a bit of a stink here a few years ago with some pex pipe - Europex - batches of it had latent pinholes from the factory and you can imagine in the early 2000s how many new houses were plumbed with it before the problems became known. The suppliers had to cough up some recompense and the buck passed to the makers, who shut down, afaik. That's why I stick to Qualpex and other major known brands.

[Fred]

Thanks for all the replies. I have a feeling that he said it was Brazilian. I notice you talk of Far Eastern. Why should the country of origin make a difference?

I had a read of the link Rick gave. I hadn't heard of the A, B, C, D grades before. Before that I thought the grades were WBP and marine or good and shuttering! Are these stamped on somewhere or do you have to take their word for it?

I will visit and have a look at what they have got.

Thanks again.

[Fred]

Thank you. Please could you tell me why it is better? And answering someone else, yes, it included delivery.

[Andy Dingley]

More resin content in manufacture, thus more water and weather resistant in service.

Mechanically I think the strength and stiffness is so near as to be indistinguishable.

[Jim K]

er..presumably it's all made where hardwood grows/is harvested....

I was offered "ordinary" and "far eastern" by my supplier - FE was more expensive and visibly "better" - fewer/no surface veneer imperfections for e.g.

Cheers Jim K

[Fred]

Thanks. All this talk about imperfections and grades made me wonder: what is the minimum grade I could use for a flat roof? It doesn't have to be pretty if it is going to be hidden from sight, e.g. under felt or up high. Do I need the best of the best? Is the problem with shuttering and other lower grades just cosmetic or are they not as strong/water resistant? Thanks.

[Fred]

Thanks. IIRC Wickes list a bitumen coated osb3, so that might be worth a look. Thanks again.

[PeterC]

Seems to be no longer available from Wickes - it's now plastic coated. The one detailed review is:

"Pros: none dont buy it Cons: not worth the money, poor quality, limited usablity now "this used to be, a bitumun/tar dipped product, that was water proof, and probably the best wickes product ever. now they have changed it, it just has a very thin plastic sheet glued on the front. and its badly glued on and peels. its now the worst product wickes have ever done. i returned them, suggested alternative. buy the plain sheets, and a tin of the cold applied tar and coat yourself. works out cheaper anyway." Expertise: Trade".