On 05/12/2015 16:16, Phil L wrote:
rick wrote:
On 05/12/2015 15:33, Phil L wrote:


Yes, use concrete cappings, timber won't last 18 months



That is not much use .... I couldn't use concrete cappings easily as
overhang would be too great ... in any event I have bought the wood.

What width is the wall?

Don't know why you think it will only last 18 months.
Fully pressure treated Tanalized timber plus finish coating on top
will last a lot longer than that ..........

How many walls have you seen with a timber capping all along it's length?
FWIW, the sun does more damage to timber than anything else - in the extreme
heat of summer it tends to twist and split, this allows insect, fungal and
mould attacks. 18 months may be a bit low, but it will rot



Unnecessarily pessimistic. The *upper* part of fences last for decades!
If the OP can engineer a small gap between masonry and wood, that would
help. Also, it's mainly water going into the end grain that causes rot.
Sealing the ends of the capping with candle wax might also help.
FWIW & IME I have both tanalised and untreated wood (above ground level)
in my garden, and they have lasted equally well. I certainly wouldn't
use a "coating", which invariably becomes a maintenance nightmare.