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Tongue and Groove Board Installation

This is sort of a "water under the bridge" issue but I thought I'd ask anyway.

What is the correct way to install T&G ceiling boards?

I have been posting on an insulation issue in the Insulation forum. I have stained and sealed pine T&G boards for ceilings. Some of the boards show signs of separating at the tongue and groove.

The T&G boards have kraft faced fiberglass insulation on the attic side. I'm concerned that I'm loosing conditioned air through all the areas where the boards are not completely tight.

I have no problem with T&G boards for ceilings, but shouldn't there have been some other material placed on the ceiling rafters first and then the T&G boards. Considering the good possibly the boards would not seal air tight, my thought is plywood or sheetrock should been installed first?

Is there a building code or standard for this? If you were to install the T&G boards, how would you do it to ensure no air transfer?

Re: Tongue and Groove Board Installation

How old is the house? I've got T&G flooring that has been down for about 140 years, it has shrunk but the tongue is still in the grove. It sounds like the T&G used on your ceiling may have been a little green when it was put up.

Re: Tongue and Groove Board Installation

I'd worry more about losing heat. Hot air rises, cool settles.
It seems like some sort of barrier like building felt or housewrap might have been appropriate. You could always use a flexible caulk and go up in the attic...but that seems like a lot of messy work.
If you do the foam insulation, it should make this a non-issue. These boards may continue to change size with the seasons, just like wood floors, but the foam should cope nicely.

Re: Tongue and Groove Board Installation

The house was built in '93. That's 1993, not 1893. So yes, something was not done correctly.

Was I'm wanting to know is, not that it would fix the problem, how are T&G ceiling boards supposed to be installed (by code or other building standard) today?

I know the boards can be nailed directly to the ceiling rafter, but is that the correct, energy efficiency, way?

Re: Tongue and Groove Board Installation

Earnie ... your local municipal building department would have the definitive answer to that question.

For example ... in this region( cold zone) it's mandatory to have an approved continuous vapor barrier on the room side of the framing ...... whereas in a hot zone like Florida it may be acceptable to have nothing on the room side of the framing.

A. Spruce
Re: Tongue and Groove Board Installation

I'm in northern California and have installed it both with and without a drywall substrate. Neither situation was commented on by the code inspector, who on one particular job had quite the keen eye for "code" problems, resulting in a 1/3 job cost increase. :eek:

Re: Tongue and Groove Board Installation

Planning to call the county building office first work day this week.

Appears there is no real standard of applying a substrate to the rafters prior to installing the T&G boards. That's odd considering today's energy efficiency goals.

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