No air should be allowed on the f.b./concrete joint. Air brings moisture form outside/inside (humidity). http://joneakes.com/jons-fixit-database/743
Foamboard installed air-tight to concrete will insulate and vapor retard
any cold moisture coming through the concrete. If you air-seal the f.b. and glue as mentioned; with the "closed grid pattern"
(horizontally and vertically) which limits the surface area of the air movement and wetness to diffuse through-- rather than drain-down to collect/pool at the bottom- possibly wetting wood framing (to mold, being organic) or cavity insulation from wicking- degrading it's R-value- if fiberglass; http://archive.nrc-cnrc.gc.ca/eng/ib...ling-heat.html
Seal the perimeter edges (canned foam) when installing against the closed-grid adhesive pattern. Mastic/tape the seams between panels, keep in mind f.b. will shrink over time (reason I typed mastic first); http://www.buildingscience.com/docum...a-foam-shrinks
Rim, as said already;
Insulating Rim Joist - caulk or spray foam around edges?
Thanks, Canucker, I was busy cut/paste my other links from other threads....!
Clothes taking longer to dry?
Clean the dryer screen in HOT water if using fabric softener sheets.
They leave a residue that impedes air-flow, costing you money.
Clean the ducting in the last six months? 17,000 dryer fires annually!