Liquid DPM applied to Plywood, will it crack as wood expands

[aires69uk]

Need to seal a piece of plywood.

I've got two options - going to be buying some liquid DPM for the garage anyway. Can I paint the plywood with this, or will it crack once dry as the wood expands or contracts?

Or alternatively, can you recommend a cheap spreadable glue I can use to bond some plastic sheeting to the plywood - 1150mm x 1150mm.

 

[davey76]

varnish ?

 

[foxhole]

Need to seal a piece of plywood.

WHY?

 

[aires69uk]

I've got some thick marine-type plywood that's going to be screwed to the joists of a shed base. It is quite thick but I don't want any moisture getting through the plywood to the shed base.

 

[foxhole]

Moisture will get to the shed base from the air and ground?

 

[JohnD]

screwed to the joists of a shed base.

do you mean "the floor?"

 

[foxhole]

screwed to the joists of a shed base.

do you mean "the floor?"

You confused as well John?

 

[nickdsjnk]

epoxy resin (west systems is good) if it needs to be totally watertight. Bond it to the joists using sikaflex or similar. Its worth mentioning that this is totally unnecessary for a shed, and is generally only used in boats.

 

[JohnD]

we still don't undertand what this ply is being used for