Here in the NC mountains, it’s common for an owner to request all or part of a house to be build on columns, with no foundation to protect the floor and its plumbing from the cold.
We typically try, if the budget allows, to oversize the floor joist depth, to allow for plenty of dimension for sloping DWV pipes and additional insulation. We mostly use insulation batts, in case any plumbing repairs are needed, it’s easier to replace than foam.
Other than this, are there any other recommended elements to this detail? Vapor Barrier? Reflective material? Heat tape on supply piping?
Thanks for any input.
Replies
bump
A couple of things:
In the circumstances you describe, placing a barrier on the bottom side of the joists to keep the rats, mice, raccoons and snakes out is a must. A heavy gauge hardware cloth or sheeting the underside with 1/4" plywood (with access panels intalled as needed) work best.
The plywood also reduces the impact of cold moving air under the structure.
I also like to install a drain valve for the water system in the event of long absences with below freezing ambient temps. (Water in pipes will freeze even when insulated given time and no water flow).