List of Stock PAR wood sizes ???

Try Wickes web site.

Why not use decking board? It's alread 150mm so you could just use 2 boards to make up 300mm.

I don't think you can get timber tanalised retrospectively.

No need if you use deck boards. Clear wood preserver after routing if not.

Just noticed Wickes is only 140mm, but you can get 150mm - I've used a lot of it.

I need 300 or so, as I need to make a 3 step staircase, and these would make the stringers. Similiar to a domestic staircase, with closed sides, and routered in treads and risers.

Why don't you just go to a timber merchant and ask for the size you want?

Deck boards, biscuit jointer (or use your router), waterproof glue?

No such thing. These are the usual nominal sizes, and PAR is about 3mm less on each dimension

I am being offered some 275 wide by a local company, made up of 3 pieces glued together (not biscuited) at £5.50/m + vat.

But they could not tell me if it would take tanalizing. I'm worried that the glue might not like it ???

Apparently 300 wide is not generally available any more as is warps all over the place. But you can get 'Southern Yellow' at £16/m + vat.

What glue is it?

Maybe you could get some nominal 225 x 38 and get the wood yard to thickness it to 30 finished size.

For unfinished wood Cuprinol Green or equivalent is pretty good, tanalising is much the same (copper based) as arsenic has been banned for most things.

cheers, Pete.

The summer before last, I made a ramp for my father's motorised electric buggy, in order that it could go to the far end of the garden (involves a step otherwise).

I made this using decking boards edge jointed in threes to make 400 and something mm width for each. This was done by planing the edges to remove excess preservative and to make a truly straight edge, the biscuit jointing using polyurethane glue in the biscuit slots and the timber edges. I put glue in the slots and moistened the biscuits. This provides the water needed to swell the biscuits and also to cure the adhesive.

Surplus adhesive is easy to remove and I then retreated the finished pieces with Cuprinol clear preservative.

At the start, I made up a couple of these and tested them destructively

- 4 joints in all. In every case, the wood split and not the glue joints.

The ramp was finally finished in a heavy grade Sadolin and with some special gritted paint for the treads. The buggy doesn't need it, but the old man can safely walk up it if he wants and can.

Any idea what the joint would be like when subjected to a period of wet weather.

Or

Does exterior grade glue, really stand up to the outside weather ??

If you choose a suitable one. Look carefully at products from the major manufacturers who have technical departments who can advise as opposed to teenagers in DIY sheds who have little knowledge of own brand Stick-it-up.

Well.... a year and a half later and no sign of deterioration of the ramp. It has been outside the whole time - it is deliberately heavy so that it doesn't move.

It has been used 4-6 times daily apart from in really bad weather and has stood up to the electric buggy - I believe they are officially called mobility scooters. This thing weighs 150kg on its own, so the fairly slight passenger does not make a large difference to it.

For a staircase, as long as you use the correct glue and make sure that edges are clean and straight and clamp during glue curing, you are not likely to have problems.