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15" batts in 24" stud centers


smcg71's Avatar
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04-02-13, 06:51 AM   #1  
15" batts in 24" stud centers

Hi all,
I have some leftover kraft faced 15" fibreglass insulation I'd like to use between 24" centers. Was going to cut 9" strips and butt them up against the 15" batts to fill the 24" gap. Will I lose some insulating efficiency or is this common practise. I'd rather not go buy the 23" wide batts if I can help it.

 
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04-02-13, 09:50 AM   #2  
Neatness counts, but what you suggest is fine. The other approach would be to cut short pieces, 23', and fit them across instead of length wise. Whichever approach, avoid a loose fit. Make them a little wider than needed and fit them in. If the fiberglass insulation has Kraft paper on it we will need to know what is under it and your climate.

Bud

 
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04-02-13, 11:39 AM   #3  
Thanks for the reply Bud,
Kinda hard to explain where I'm installing but I'll give it a shot. My bedroom is a loft style bedroom. Behind the side walls, the roof line continues down to the soffit which creates an "attic" area behind the wall. There's old insulation in there that was never installed properly resulting in an extremely cold walk-in closet in winter and extreme hot-humid in summer. I want to re-insulate between the 24" on center studs behind the drywall. (Make any sense???) I'm located in Windsor, Ontario, Canada which is on parallel with Detroit Michigan so cold winters and hot-humid summers. Thanks again


Steve

 
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04-02-13, 12:23 PM   #4  
Hi Steve and welcome to the forum,
Those side attics are common and difficult to get insulated. If you are putting the insulation on the floor and the back of the short wall (kneewall), then you should also block each floor cavity so air cannot circulate below the kneewall under the finished room. You should also cover the back of the kneewall to reduce air currents that reduce the insulation value. But not a vapor barrier. House wrap, drywall or similar will allow some drying to the outside so that any moisture that gets past the inside drywall can continue through and out with the venting.

Now, the bad news. Closets that don't have a source of heat or ac will always be hot or cold. Plus, the cold walls in those closets can often result in condensation and mold. If you add a lot of insulation, think r-50, then a small amount of heat will keep the space warmer. But if that is 3.5" fiberglass, I doubt you will notice any change.

Before I go on, confirm my description or am I lost?

Bud

 
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04-03-13, 06:43 AM   #5  
You're right on the money Bud. The "floor" of the attic area is fully insulated and the kneewall is also insulated but the house is 100yrs old and the insulation is falling down and insufficient. Since there's no way of adding duct work to the closet I may install a power vent on one end of the closet to blow the warm or cool air from the bedroom into it and a return vent at the other end of the closet so the air circulates. Thinking this might be better than nothing??? Thanks alot for your replies. The internet has made a do-it-yourselfer outta guys like me thanks to knowledgable people like yourself. Appreciated.

 
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04-03-13, 08:18 PM   #6  
Since there's no way of adding duct work to the closet I may install a power vent on one end of the closet to blow the warm or cool air from the bedroom into it and a return vent at the other end of the closet so the air circulates. Thinking this might be better than nothing?
If the space behind the kneewall is your walk-in closet and you're thinking of sharing your heat and a/c with it, then you need to insulate it as part of your conditioned space: Insulate above and on the outside of it. Don't insulate the kneewall or the floor under the closet.

Otherwise you'll be spending money to try to heat and cool the great outdoors.

 
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