Originally Posted by Jungle
2" Of Styrofoam around the outside should make the concrete walls much warmer.
Good link about heat transfer and vapor transfer. I'll have take notes on this video, it goes fast.
Here are my unedited notes from the cold climate video which may serve as a checklist.
It seems that for existing construction, you'd need some way of measuring vapor and water transfer, relate that to basement comfort and decide what your comfort is worth in dollars.
Cold climate research
-below grade heat loss is outward, vapor pressure is inward.
-above grade, in winter vap out, in summer it's in.
-understand moisture flow, liquid and vapor
-capillary wicking water upward. Need a capillary break between footing and foundation.
-vapor comes in two ways, by air and diffusion (pressure), Soil is 100% RH.
-preferred is to put water membrane (spray on or roll on) and insulation outside so water & vapor does not saturate the walls. Then the wall stays warm and if any moisture is in the wall it can rapidly be dried out by the basement air.
-basement wall moisture content strongly predicts joist moisture content by vapor transfer. Joist insulation makes it worse. So extend the outside insulation over the rim joist.
-You can insulate from the inside but it has to be perfect because the wall moisture control has not been taken care of. The cold basement wall will get condensation. And if your basement floods the interior fiber insulation has to be removed.
-You could use styrofoam on the wall interior but basement wall surface has to be dry. The bottom foam edge needs to be sealed.
-The slab has to stop water from underneath so use aggregate to allow drainage and prevent wicking.
-Seal the sump lid to prevent humid air coming into the basement.
-Use a thermal barrier under the slab because warmer is drier and the slab becomes part of the conditioned space.
-Don't carpet the slab.
-The lump sum cost of exterior insulation may pay for itself over time. This insulation needs to be protected from physical damage. Interior insulation systems are risky but may be cheaper in the short run.
-Use paperless drywall for finishing, no insulation, use flat latex paint.
-The rim joist should also be part of the conditioned space.
-You could use spray foam inside but it may not bond properly. The joist may absorb moisture.