Wall Condensation Check

Will moisture condense inside your wall? Temperature through the wall vs. the dew point. Free, no sign-up.

Warm indoor air carries moisture. If it reaches a surface inside the wall that's colder than its dew point, it condenses. The risky surface is the inside face of the sheathing, or of foam board if you have it.

Insulation outside the sheathing keeps that surface warm. NBC Table 9.25.5.2 sets a minimum ratio of insulation outboard vs. inboard of a low-permeance layer, based on how cold the location is.

This is a steady-state check at the temperatures you enter — a good screen, not a full hygrothermal model. Air leaks carry far more moisture than diffusion, so an airtight interior matters most.

Taulien Construction · Fredericton, New Brunswick · info@taulien.com · 506-230-5131