Why timber? Softwood, which is cheap, will warp and rot in situations where it is contact with the ground. Dense, tropical hardwoods are better in that sort of situation but are expensive and it is often difficult to prove that they come from a sustainable source. Any timber would need to be cut to a large section so as not to warp (say 35mm x 75mm for hardwood) and should be fixed to a metal shoe of some sort, so that it is not in direct contact with the ground.
Have you thought of having a steel rail made up? this would contrast well with almost whatever surface it is going into and would last longer than timber. A cheap alternative would be a simple flat topped 255mm concrete edging, set to protrude above ground level.
Pete Leaver MLI
David Wilson Partnership
The Old School
Ladywell
Pilton
Barnstaple
Devon
EX31 1QT
tel 01271 374485
fax 01271 345544
mob 07979 755986
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