Rigid foam insulation on top of a concrete slab
Weather zone 4 C (on an island in Canada just north of Vancouver). new construction of small cabin. the plan is to pour a slab of concrete on top of a bed of gravel over sound subsoil, then lay stringers of 2×4 on end with rigid foam insulation between the stringers. Top with 3/4″ ply sub-floor and 1/4″ nail-through oak flooring.
Decided not to put insulation under the slab because of potential infestation by termites / carpenter ants.
Question is what type of foam insulation, how much (R value), what about vapour barrier? The cabin will be measure 11′ x 20′, be heated by a wood stove / heater.
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