flooring options

[Matt Green]

If you have the Celotex laid over the joists, directly under the boards you would have an impervious barrier to water. That's not a clever specification because water will condense on the Celotex and run into the joists. That could be the fresh water source you are looking for.

Need a picture/diagram/confirmation of the specification, there are too many unknown variables at the moment.

 

[MdB]

If you have the Celotex laid over the joists, directly under the boards you would have an impervious barrier to water. That's not a clever specification because water will condense on the Celotex and run into the joists. That could be the fresh water source you are looking for.

Need a picture/diagram/confirmation of the specification, there are too many unknown variables at the moment.

Condensation if any would form on the warm side (top) of the insulation and Celotex being waterproof won't let too much through to the joists - especially if the joints have been taped as they should. I wouldn't expect any condensation on the cold side (bottom). I also don't have any trouble with an impervious barrier if the underside is well ventilated.