vapor barrier question

ratherbefishing · 12-18-2011, 08:22 PM

I got the insulation up on the walls of the addition today. Looks pretty good, BTW. Question is: Due to window placement, king studs, etc, I have plenty of stud bays of less than 16" OC. So the batts only have staple flanges on one side now. Should I tape up where the face doesn't overlap the studs? Or not a big deal?

Thanks!

**Gary in WA** · 12-18-2011, 08:50 PM

You may not want a vapor retarder (faced) insulation due to the exterior wall make-up; http://www.buildingscience.com/docum...tlanta-profile

Faced insulation is area weighed- holes, slashes, etc. are not important; http://www.insulating-products.com/p...lation_FAQ.pdf

The facing is variable permeability with the increased moisture content. No tape, just don't side staple rather than face staple for convective loops.

Gary

ratherbefishing · 12-18-2011, 09:26 PM

Thanks, Gary. That Johns Manville doc had the answers to all my questions. I hate to admit that I had found that doc a few weeks ago, and had forgotten about it.

My recessed ligt cans are IC rated. I didn't notice that they were insulated, tho. I'll probably end up with a gap around them anyway.

I have 1/2 a roll left over. Is it worth putting some in the interior wall for sound deadening? The plumbing is right behind the headboard.

**Gary in WA** · 12-18-2011, 09:46 PM

Long as it's left-over.... I insulated my pipes and stairs back in '85 on the addition here, before it was popular. F.g isn't the best for sound, though not bad. Sound board and two drywall layers through-out on my next house (super-insulated)... thermal mass for my solar closets and sunroom H.W.pre-heater.

Gary

ratherbefishing · 12-18-2011, 10:29 PM

Do you think some foam on the pipes in the wall may help, sound wise? I thought about slipping some drywall behind the pipes. I'm sure I'll have plenty of that left over, too. And the stuff in the existing wall is 3/8.

**Gary in WA** · 12-20-2011, 11:27 PM

Might help insulate them...... from cold/hot. Stuff them with drywall after isolating them with foam, you don't want conducted sound. Check pipe touching bottom plate/top also, should be clear (other than fire-stopping foam between floors) everywhere but to the fixture. Pad the hangers, especially if suspended from an engineered floor system. If needed, I'd use rubber blocks under washer/dryer, under garage door opener fasteners, rubber mat under/behind microwave/computer printer/refer motor, felt tips on chair bottoms/door stops/cabinet doors, and sound board around the built-in dishwasher (my next one's a Bosch...lol). I even added dabs of silicon on the nail guns for work....................................... for lowering them on air hose to concrete slab... made you think for a minute on that one??

Gary

Gary