I will be laying a new deck on old hardwood joists, the joists are
pretty sound and I recon there is between 6 and 10 years left in
them.
However, I don't want to contaminate the new deck in any way from any
residual wet rot (even though I will be treating the joists) I was
thinking about plastic DPM between the boards and joists but am wary
of moisture being retained under the boards, does any one have any
cheap alternative to this that would allow a small air gap?