Vinyl over insulated floor on piers in cold climate
Hi, I have a cabin on piers, with insulated floor. The joist bays are filled with fiberglass bats, bottom side is covered with 1/2 chipboard, sealed and battons at the seams. Vapor barrier on the top / warm side, and 3/4″ t&g plywood over that. So far it’s been warm and dry and critter proof. I’m in Canada, winter temps in the -5 to -25 deg C are not uncommmon.
I’ve opened it up in a couple of sections on top (after @ 20 years in service) this year to run some subpanel wiring and drain lines etc in the joist bays, as part of a remodel I’m doing – and the structure looks like the day I put it in – nice and clean and dry, at least where I can see. It’s been a “camp” so there hasn’t been any flooring installed over the ply, just left it as is until now.
Here’s my concern – I’ve been reading some threads here and I notice that some of the experts are leery of putting vinyl flooring down on top of an insulated floor in some circumstances, as the vinyl is impermeable. I have a supply of Armstrong click vinyl that I got a good deal on, like the way it looks and easy to lay down. I plan to install soon and I’m thinking that this will be no different than the vapour barrier that’s already there in my case from a “breathable” perspective. I’m assuming the floor breathes out the bottom chipboard to some extent and this won’t change.
It would be great if you folks here could offer up your thoughts on this. It seems I must have done something right back then, as it’s still solid and dry, but I don’t want to screw that up now.
So any sanity checks are much appreciated.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Replies
Randy,
Problems can occur with vinyl flooring over insulated floors in a house on piers -- but those problems happen in New Orleans and Houston, not Canada. The problems happen when the house is air conditioned. If your vinyl flooring is cold, it can become a condensing surface during the summer, especially if hot, humid exterior air can enter the floor assembly through cracks.
So don't worry.
Martin - thanks for taking the time to sanity check this, much appreciated...
To add to this: we have a house on Long Beach Island, NJ. Virtually all homes on the Island and much of the Atlantic coast are built on pilings with the floor insulated. I would venture to guess that tens of thousands if not millions have vinyl flooring and no one seems to be worried. This climate is warmer than yours; but more humid.... and temperature swings can be intense due to storms and the temperature gradient between the ocean water and air...
Many of these houses are high enough off the ground to park cars below the main floor. Interestingly, fire code requires that these all need double layers of 5/8 sheet rock as the bottom layer (whether the ground floor is enclosed with breakaway walls or left open). The sheetrock is painted and taped and often left exposed this way on homes where the ground floor is not enclosed.