Room overhang is cold

Reply

  #1  
Old 11-10-19, 03:18 PM
Z
Member
Thread Starter
Join Date: Jan 2018
Posts: 434
Received 0 Votes on 0 Posts
Room overhang is cold

Our family room (upper floor) has a partial over hang.

The floor above the overhang gets very cold in the winter. There is a heating vent outlet located along the right hand side of the room, but 3/4 of the way back from the 2 large upper windows you see.

How should the area in the overhand be insulated? It’s covered right now in soffit. I’ve yet to remove the soffit. Should there be bat insulation in the floor joists?

There’s also a rather large gap above the door.....between the door and the soffit. What could I fill that with?

Any other ideas to make that area warmer? The previous owner disconnected and removed a baseboard heater located under the two windows. There is still a baseboard heater (disconnected) along the right had side wall next to the downspout. Its position is useless as our couch is along that wall.

Room is facing south so we get a lot of sun, but if the wind is blowing at all, or in the morning, the floor is very cold.
 
Attached Images  
Sponsored Links
  #2  
Old 11-10-19, 04:35 PM
XSleeper's Avatar
Group Moderator
Join Date: Dec 2004
Location: USA
Posts: 25,991
Received 667 Votes on 617 Posts
Air sealing all the outside edges is important. Often when fiberglass is used, it lays between the floor joists, leaving a gap above the insulation where air can wash down the joists directly under the subfloor. And air can pass through fiberglass since it only slows air... it doesn't stop it. So fiberglass is not the best way to air seal. Foam is better, but you must still seal the edges so that air can't go around it.

So on a cantilevered home, you would really want to seal the rim joist and the bottom of the joists, which is now covered only with plywood. There are likely lots of gaps allowing air in. Then the joists avove the cantilever can be filled with insulation, with no worries that exterior air is washing through it. There is no point in filling the joists with insulation once you get past the interior wall surface of the lower level.

As far as disconnecting heat is concerned, that is probably the worst thing you could possibly do, especially in an area that probably experiences the most heat loss. BTU heat loss can be calculated by an energy audit. The way to keep rooms comfortable is to throw more heat (BTU's) at it. By shutting the heat off, you are doing the opposite, so the room will get much colder as a result.

As far as your door question is concerned, I don't know exactly what gap you might be referring to.
 
  #3  
Old 11-11-19, 05:44 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 59,058
Received 1,109 Votes on 1,029 Posts
It is amazing..... all these years of using the cantilevering method of building and still not insulating correctly. I worked on a customers house during then week. I was installing alarm contacts on windows in a cantilevered kitchen. The tile floor over the cantilever was ice cold and there was a breeze. Customer had no idea why. I knew.

If it was me..... I'd have it professionally spray foamed.
 
  #4  
Old 11-14-19, 04:24 PM
Z
Member
Thread Starter
Join Date: Jan 2018
Posts: 434
Received 0 Votes on 0 Posts
What’s the next Best thing to spray foam and diy? We live in a small rural community....not sure how available spray foam is for such a small job.

Does r10 rigid with r35 batt make sense for Canada?
 
  #5  
Old 11-14-19, 04:38 PM
T
Member
Join Date: Aug 2018
Location: Canada
Posts: 95
Received 4 Votes on 4 Posts
Rigid foam board with all edges caulked would also prevent air flow and be a better alternative to fiberglass batts. The foam board needs to be layered thick enough to provide you with the required R value.
 
  #6  
Old 11-14-19, 04:52 PM
Z
Member
Thread Starter
Join Date: Jan 2018
Posts: 434
Received 0 Votes on 0 Posts
Ok thanks. Home Depots website says I need r45. Not sure I could get that with just rigid.

If I did rigid and batt....which gets installed first? Or do I do rigid, batt, rigid? I really want to insulate the bottom of each joist and stop that heat loss too.

Can the soffit go directly against the insulation? Or does plywood need to be installed between the whatever insulation and the aluminum soffit?
 
  #7  
Old 11-14-19, 05:06 PM
Z
Member
Thread Starter
Join Date: Jan 2018
Posts: 434
Received 0 Votes on 0 Posts
Can I expect to find that the floor joist are completely open without any blocking (meaning the floor joists are open the entire length of the house?)

Would it make sense to add a blocking piece of wood (where the main plate for the wall meets) as shown in these photos where this guy is demonstrating his open floor joists and putting in strips and a blocker piece? And then insulate that too?

Or do the floor joists need to breathe?
 
Attached Images   
  #8  
Old 11-14-19, 08:45 PM
XSleeper's Avatar
Group Moderator
Join Date: Dec 2004
Location: USA
Posts: 25,991
Received 667 Votes on 617 Posts
Yes, that's what I was saying. Your floor joists are open all the way through the house, so any cold air that gets in will wash down the entire floor.

So as I originally suggested in my first reply, you should put rigid foam against the rim joist (which is the outside board that all the joist are nailed to.) And seal the edges with caulk, spray foam or foam adhesive to make an air tight seal. Use as much foam as you like. Thicker the better. 2 layers of 2" would be sufficient IMO. Then you also have to seal the bottom of the cantilever the same way. Can't see how it was framed so it's hard to advise specifically. But you should be able to drop foam over the top plate between the joists until it sits right on top of the plywood soffit. Seal it the same way.

Once you get it air sealed, you can fill the rest of the space between the joists with the insulation of your choice... fiberglass, rock wool, Roxul, whatever. It does not need a vapor retarder (kraft facing) unless that makes it easier for you to staple it up. You could also put up insulation fabric and blow it full of cellulose or blown fiberglass.

R45 is what you might put in an​​ attic. You do not need exactly R45 there. You just want to get as much R value as you reasonably can. Your walls above and below are likely only R11, if that puts it into perspective. And no, you would not really want to use foam, then loose insulation then more foam. You could put a piece of wood blocking in (same dimension as the joists are) on the interior side of the lower level's top plate but it's not necessary, unless that is your means of holding the loose insulation in.
 
Reply
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: