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insulating a subroof

Taylor | Posted in Energy, Heating & Insulation on November 10, 2004 12:14pm

Over about half of my kitchen is a subroof extending out from the side of the house. There is currently no insulation there (I was wondering why the kitchen was so cold…). I plan to insulate thusly:

(1) Replace the existing recessed cans in the kitchen ceiling (half of which don’t work) with new ic-rated airtight cans.
(2) Spray polyurethane foam on the interior of the subroof to close up air leaks.
(3) With the floor already up in the room above, I plan to blow cellulose on the new kitchen ceiling from above when (1) and (2) are done.

(1) and (2) will require taking down the kitchen ceiling.

Question: Is there anything wrong with doing (2)? One of the reasons for doing (2) is that it’s my understanding these subroofs extending from the side of the house are a big energy loss. So this is for the whole house, not just the kitchen, only 1″-2″ DIY SPF to close air leaks to outside. Dense-packing isn’t really an option in this case. (3) is specifically for the kitchen, 3″-5″ cells.

Reply

Replies

  1. rez | Nov 12, 2004 05:28pm | #1

    bump

     

  2. rez | Nov 16, 2004 05:16am | #2

    bumpity bump

     

  3. rez | Nov 22, 2004 06:06am | #3

    pump and dump

     

  4. rez | Dec 03, 2004 10:50pm | #4

    Tempted to say 'poor taylor' no response.

    But 200 posts here since sept. is close enough to being a regular so he can just wrassle around with the rest of us.

    be kneedeep

     

     

  5. Piffin | Dec 04, 2004 01:35am | #5

    praisw rez for his persistance. This is the first I have seen this thread.

    I'm not sure I understand all the details.

    But spray foam is undoubtedly the best solution from the insulation/ventilation viewpoint, IMO.

    Since that uinvolves taking down the cieling - at cost - I would consider denscells for this though. The savings would be considerable.

    Hope this is not too late to help.

     

     

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    1. User avater
      Taylor | Dec 04, 2004 02:25pm | #6

      Thanks guys, I know I ask a lot of questions, usually of the anal variety, so no problem if not everything gets answered.... I'm a little more familiar now with the roof venting controversy. I have soffit and ridge vents in the main attic, but no way I was going to vent cold outside air into the space right over the kitchen. So this is unvented to the outside. Right now this roof area is exposed to the space between first and second floors, due to suspended ceiling, I'd have to block it up to dense pack. I still like the foam, in addition to cells, to avoid the VB controversy: put the dew point in the foam and allow some small amount of permeation.... I guess in this case the foam would be on the outside in a heating climate, but it would just not be possible to spray foam on the ceiling....Anyway looks like I'll have to miss the opportunity to blow cells in while the floor above is up, DW ruling it out, one room at a time. So I may be back to ask how you can blow cells in an unfinished ceiling area (wet cells: worry about moisture build-up in an enclosed space; plastic: worry about heat from recessed cans), actually with 20ga steel studs and metal hat furring suspended from them.... Hm, why not ask now?

      1. Piffin | Dec 04, 2004 06:53pm | #7

        Foam is probably best for you but it is not hard to do cells agaibnst roof sheathing with unfinished cieling. The instaler staples up a fabric and cuts slits to introduce the hose.He might use a VB type fabric or add the VB later.With enough cells or with foam, VB is not an issue, because there is no dew point for condensation to occour. I prefer chpped FG BIBBsystem for blown in like this, Mike likes cells, but if cost is not a major hurdle, you cannot beat foam. With urethene foams, it is a VB itself. ICY is not a VB but again, if enoufgh used, no dew point existsBut a major advantage of a foam sprayed system is had when you do whole house and seal infiltration at the floor level, you reduce convection loss of heat. 

         

        Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

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