Sterling board or T&G for shed roof

It's good for that sort of purpose, I'd say.

Sterling board or OSB is NOT waterproof. Some grades are 'moisture resistant', but not waterproof. The resin used to bond it together is waterproof, but not the finished product.

Wickes used to sell waterproof OSB - it was black & seemed to be coated with some kinda tar. They apparently stopped selling it because the black stuff contaminated everything that touched it.

OSB (sterling board) is as good as T&G, it's thicker and isn't as prone to rot as T&G. Obviously you'll be felting it?

I'd say there's an advantage to not having T&G and I'm more or less in sympathy with the shed makers statement, since felt over T&G does seem to break along the seams. I was going to whine about Sterling board as a low quality, cheap solution but my own shed has a Sterling board roof with a double felt layer, and it has stood up to the elements for sixteen years. So I can't see a problem with it.

I'm not sure I'd claim total impermeability, but it doesn't instantly turn to Weetabix. Unable to find some paddles when testing a mate's borrowed boat, I quickly knocked up some "temporary" ones out of 2x2 and some OSB offcut. We never got round to replacing them and so they've been dunked in seawater for hours most weekends for the past couple of months. No obvious signs of deterioration.

Pete

I made up some temporary exterior doors from OSB - which actually ended up staying for 18 months. No additional protection, quite exposed to wind/rain/sun. A little water damage was starting at the bottom, but by no means was it falling apart.

Another alternative is exterior grade spruce ply - about the same price as OSB - or an even better grade of ply if you're ok with the cost.

failure

wrinkle

waterproof

Use OSB3 which is waterproof - do not use OSB1 or OSB2

AWEM

To reinforce this I made my kids' fortress with an OSB skin that has just had normal B&Q fence paint on it - it seems to be standing up to the weather so far... (2 years later)

Mark

(Hopefully this won't post multiple times but I had problems getting it to send at all)

This must be what I got. Some boarding had been taken off the windows next door (council house) and dumped in the garden, so I 'liberated' it. Used some for a cover on a water butt, so it's nearly horizontal and, of course, doesn't dry out underneath. It's abit soft on the surface underneath but still OK after about 15 years.

Hi,

Thanks everyone, that's put my mind at rest.

Martin.