Skid shack vapour barrier?

[ditch donkey]

So I’m doing some Reno’s on a skid shack I have out on a property. The walls have OSB on the inside. I had to remove an OSB panel and saw there was no vapour barrier behind it. I originally thought the previous owner had put the OSB up, but now looking at the workmanship, copious amounts of adhesive, and the way the wall panels continue behind other walls I’m confident that there was no vapour barrier installed at the factory.

Is vapour barrier not necessary on a Skid Shack type structure? It would be a ton of work to strip all the OSB off, add the poly, then probably put OSB back on. From the inside it goes-

OSB
Fibreglass insulation
Plywood
Metal siding

The shack is heated by wood in the winter.

[jstubbs]

Skid shack falls under Part 10 of the Alberta Edition of the NBC. You really only need electrical, plumbing and gas certs for the structure to get your permits for reno. No vapour barrier required albeit it is best practice, but so many were built fast/cheap as possible or were repaired that way so ended up without.

[CBintheNorth]

Typically I would say you would definitely want vapour barrier.
However considering that it is wood heat, I wouldn't be as worried about it.

[ditch donkey]

Thanks for the responses.

I suspected skid shacks fell under a different code. If they didn’t use adhesive to bind the panels to the walls I would strip it and install the vapour barrier. The Insulation under the sheets I did take off looked really good so I think I’ll Leave it as is, maybe install more ventilation.

[obsessed1]

According to ABC certain wall coatings ( paints) are considered vapour barrier. Not preferable but can meet code. On a shack heated with wood...I probably wouldn't worry much about it.

[jstubbs]

Originally Posted by ditch donkey

Thanks for the responses.

I suspected skid shacks fell under a different code. If they didn’t use adhesive to bind the panels to the walls I would strip it and install the vapour barrier. The Insulation under the sheets I did take off looked really good so I think I’ll Leave it as is, maybe install more ventilation.

Who is the mfg and what approx. year of build?

Most skid shacks these days (and for the past 20 years) are drywall with battens instead of mud/tape screwed to the studs, plastic vapour barrier between, then fibreglass insulation, plywood, tyvek, tin siding.

I would also check to see if it already has a Part 10 label on the exterior, which is supposed to show your shack is certified Part 10 relocatable structure that has been approved under ABC. If the decal is missing you will need to contact your authority having jurisdiction to inspect the shack's applicable plumbing/gas/electrical, and then they request a green label Part 10 decal from Municipal Affair's Building Administrator. Or maybe you request it after receiving those inspections... can't remember how the process works exactly as we did it a little different... lol. If you are stuck PM me I have a good contact with Municipal Affairs but otherwise a simple call to your county office should help get you the right info needed.

Again this is all assuming you are concerned with this and weren't just asking for the sake of curiosity behind how they're built.

[Dewey Cox]

Just curious why people feel wood heat means you can do without vapor barrier?

[jstubbs]

Originally Posted by Dewey Cox

Just curious why people feel wood heat means you can do without vapor barrier?

Wood heat produces less interstitial condensation than “wet” LPG heat, making a vapour barrier less necessary is my guess. IMO worthwhile to have a vapour barrier just to help keep the inevitable mold at bay

[Texican]

I think plastic paint or other plastic coating is now considered a vapor barrier.

[ditch donkey]

Originally Posted by Texican

I think plastic paint or other plastic coating is now considered a vapor barrier.

It probably is. I’m going to seal the seams with wood filler and sand, then 2 coats of oil base primer. I’m certain it will be “fine” but it is not going to be the same as a proper poly vapour barrier.

[MyAlberta]

May have originally been built without heat, so no need for vapour barrier. Heated, or ‘conditioned’ space requires vapour barrier when insulated.