How to insulate living space over porch
See attached picture.
What you are looking at is trusses that are cantilevered over an exterior wall and then again cantilevered at a 2×10 header. Above all of that is living space (you can see the subfloor up there).
I currently have OSB nailed in between the trusses to keep the bugs out, but as you can imagine there are quite a few gaps in there. I plan on framing the porch ceiling at the bottom of the 2×10 header which will come across and hit just above the existing trim on the windows.
So how to insulate this? First I need to decide on basic approach. Do I insulate on top the exterior wall and then up against the bottom of the floor, or do I do the complement of that and insulate on top of the (not yet framed) porch roof and up the outside rim joist area (on the right side of the picture).
I’d like to just have somebody use spray foam on it, but as of right now the spray foam guy doesn’t return my calls. So I might have to do it myself with rigid foam. I could put rigid foam in between the trusses and foam them in place and then do the same on the underside of the floor (4″ foam gives me R20). Or I could put rigid foam at the rim joist and on the underside the floor trusses, seal it up well, then blow in some loose insulation.
MERC.
(sorry for the double picture post – they are both the same)
Replies
Just giving myself a bump hoping the weekend will bring a few ideas from the group.
Thanks MERC
This is exactly like the floor / ceiling in my garage. Truss overhead that forms the floor system of the living space above. I am blowing it full of cellulose. FULL!
In your circumstance I think I would blow it in then sheet the bottom cord of the trusses with osb (1/2"). Then anything else underneath is just other and not involved. And if you are in a really cold climate, why not put some pex tubing in between the truss bays on the bottom of the floor. Don't hook it up to anything but if your feet get cold over the next real cold spell you have the option to hook it all up to a hot water look and warm up the floor a little. I did this in my breakfast room which cantilevers out over my walkout basement door.
Good luck,
Rob Kress
I would have to sheet first, then blow in right? And is your blown in dense pack or loose? I was worried about loose fill letting air current through and reducing the effectiveness. I'm in NC, so we do get some cold, but nothing really that bad.
MERC
I may be wrong but I believe he was referring to a wet blown Cellulose that stick and is a hard pack --that way you can get inside of all the webs. once your done the pack will dry and you can sheath it.
Spray foam will do the same thing spray-set-and sheath. I think I would stay away from Fiberglass cause your overhead (and will all know how much fun that is) and it would be tough to get around all those webs.
I would agree that full would be fine in that you aren't trying to vent and you only get one chance to keep the floor above warm.
we know something about staying warm around here in Mn. Good Luck MIke
i don't think he was referring to wet pack.. he should be using dense-pak..
blow the void solid.. you can sheath the bottoms of the trusses with 1/2" or even 3/8" .. leave some slots so you can get your hose in and snake it all the way to the ends..
or..
you can sheath the bottoms and blow the voids thru the subfloor..
what's up with that beam ?
View Image
Mike Smith Rhode Island : Design / Build / Repair / Restore
Edited 9/18/2004 7:54 am ET by Mike Smith
Sorry for the confusion guys......
I will not be doing it myself... the insulator will be doing it. It will be blown in dry with a lot of pressure so that it will get dense. And to keep it in place, the insulator first puts up a very thick, heavy mesh type stuff stapled to the bottom cord of the trusses. Then, the blowing buy comes buy and cuts selective holes and pushes the hose around to fill the cavity full.
In your case, this would be perfect and then you can sheet over the mesh to finish it all off. I would not just leave the mesh to hold up the insulation of an extended period of time.
Is this more helpful?
Rob Kress
Yes you are correct-dense pack- I f the insulator uses mesh to support the pack just make sure he doesn't pillow the mesh between the trusses so that you don't have to struggle compressing it to get your ceiling on flat. Is that mid beam for roof load? Nice porch area look like it would make a great place to hang out. MIke
The mid beam actually carries very little load. The engineer computed minor uplift at that beam. Most of the floor load is carried by the exterior wall.
Here's a picture of the front of the house, and since you said you liked the front porch for hanging out, you might want to come out back and have a beer and some steak right off the charcoal grill. The second picture is a little messy, we have cleaned up since then, but you get the idea.
MERC.
dj... that is going to look so great with RC ...
what city are you in.. ?Mike Smith Rhode Island : Design / Build / Repair / Restore
I am in Chapel Hill, NC. I should update my profile someday...
Yeah, anytime anybody is around here, stop on by for a beer and NY Strip right off the hot charcoals.
Thanks for all the help!
MERC
Holy smokes--Nnnnnnniiiiiiccccccceeeee. Please tell me that that is a ranch(rambler) bones under that beauty. If I ever come close to your neck of the woods i would love a tour and some scketches. as long as they came with a beer and a sit on that porch .
would love to see the job along with a few more pictures when you get there.
Hope all goes well and remember " nobody ever won a bar-b-que contest on gas" LOL Mike
Wheew! That really makes a diff. Stuck a couple of your shots together to see the difference.
jt8
Mike
The strange beam is a by product of remodeling. Here are a couple of pictures to explain what is going on. Basically I have a 12/12 roof built on top of my original house. The front porch area is actually carved out of the 28x54 house foot print that I have. So the architectural drawings show a double 2x10 that lines up with the exterior wall on the end of the porch (see Header In Front of Wall picture). You can see that the centerline of the masonry columns didn't line up with the existing exterior wall. So the double 2x10 got pushed forward of the existing wall, but for a few trusses at one end of the house, I couldn't push the trusses longer because that would have screwed up the 12/12 roof plane. there is a large cross gable in the front of the house that allowed me to ride most of the trusses on the double 2x10 pushed forward. But for a few trusses I had to bolt another 2 2x10's on to pick up the trusses.
Man if you followed all that....
MERC.
thanks for the pictures--if you get a chance at the end I would love to see the before and after. Never been to NC. but then again I never had an invite. If not maybe we will meet at a FHB or other trade show. See ya on the next thread. Nice to meet you. Mike
PS Ever get to MN.
You might be able to foam this yourself. The Energy Federation (http://www.efi.org) sells foam in BIG canisters, containing many, many cubic feet. Set up a commercial account with them. It's quite easy, and the discount is worth the trouble.
Andy
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