I live in Houston, worked in residential construction for over 25 Years, learned something new today. Insulation in wall cavities to be placed with vapor retarder (kraft or foil faced) facing outside of wall? Say it isn’t so…. If this is true, I’ve messed up more than just a few times. Also seen alot of others do what I thought was correct and install vapor retarder “to the conditioned” or “warm-in-winter” side. What gives?
Discussion Forum
Discussion Forum
Up Next
Video Shorts
Featured Story
Listeners write in about ambitious projects and sinking patios before asking questions about old house specialists, attic headroom, and home shops.
Featured Video
Highlights
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Fine Homebuilding Magazine
Fine Home Building
Follow
-
Fine Homebuilding
Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.
Start Free Trial Now -
GBA Prime
Get instant access to the latest developments in green building, research, and reports from the field.
Start Free Trial Now
Replies
In most places, the vapor bar to the inside is correct.
Joe Lsitubrek (sp?) at building science has been at the forefront of a new understanding of this tho. His theroies, as I understand them, are that since a warm humid climate such as yours requires the vapor bar on the outside.
Reasoining is that since homes nowadays are airconditioned, the humidity moves from warm wet space (outside) to dry cool space and possibly - according to conditions present - condenses at some place along the way. This is thew opposite of northern climates where warm air in winter moves moisture towards the outside and creates a possibility of condensation where it hits cold spots. The ionterior VB keeps the moisture out of the walls there.
So in your case, as the theory goes, the VB on the outside keeps the humidity from getting trapped in the wall where it can cause molds.
I don't live in the south anymore so I can't testify to p[ersonal knowledge but the idea makes some sense.
Excellence is its own reward!