Spray Foam Question

[Dutch445]

i have a modular built cape, and prior owner's finished the "attic" into 2 bedrooms and a bathroom.
there is a flat ceiling in the rooms, with unfinished cold space above.
differences here that i can point out is the modular came with the main level ceiling insulated and
plywood on top of the joists to create the 2nd floor. I have done some remodeling of that bathroom
and noticed it was insulated well. it's above this level the problems start. the roof system
of these modulars comes folded down for transport, and i believe they hinge the top portion up into place as they set
the sections together. this roof section seems to be made with 2x4's with a lot of extra cross bracing etc.
in comes somebody to build rooms, and knee walls are built 4-5' in from the eaves. sheetrock was put on
the bottom of the 2x4 rafters for the sloped portion of the ceiling . bat insulation on the top of the ceiling, in the roof rafters between the
sheet rock and plywood on the sloped ceiling, and then bat insulation in between the knee wall studs.
cold cold cold up there, as i'm sure it was very shoddy work to begin with, but by insulating the sloped ceiling
it cut off airflow from the soffit vents up to the attic ridge vent. so the soffits and behind the knee walls is cold air
with no place to go, and i'm sure it comes thru the wall. in the attic all insulation ends up above that ceiling,
of which i posted a picture. (first thing we did after closing was have all that insulation re-positioned as in
the picture it's quite scattered!)
i have pondered the same question. tear off the sheetrock, spray foam it all and close off the eaves,
or, build baffles and then spray foam, but with only a 2x4 to work with by the time we install a baffle
it doesn't leave much room for insulation. then i'm not 100% sure that those areas on the sloped
ceiling that are sheetrocked don't have a cross brace in like there are above the ceiling.
currently we have those rooms closed off, nobody lives with us, except for when we have visitors.

 

[scott_vt]

Good Afternoon Tim,
I used conventional fiberglass insulation when building the addition on my Vt home. I had the thread of this project posted in this forum, don't know if you saw the thread or not.http://www.tractorbynet.com/forums/projects/312830-familyroom-addition-our-cabin.html

The addition was 18' by 28', and we used 8/12 trusses on 24" centers. Using these trusses gave us a 14' wide room upstairs with a 4' knee wall. I stapled Perma Vent to the roof sheathing in between the trusses giving ventilation from the eaves to the ridge vent. I used conventional faced fiberglass in between the trusses from the roof peak down to both of the knee walls. The family room ceiling was also insulated using conventional faced fiberglass R-38. We wanted a bit more insulation in that ceiling, so we blew in some cellulose insulation on top of that, and then insulated the knee walls.
We haven't really gotten into any severe cold weather yet, but so far I am thinking this room is going to be easy to keep warm. We used 2" by 6" wall construction, again using fiberglass faced there also.

I am not sure you can tell by the last picture, but the insulation hanging down from the ceiling, drooping down between the trusses, along with the added weight of the blown in cellulose, made for a real chore trying to put up that V groove pine ceiling, since I was working by myself !

But we managed to get it done !

 

[Dutch445]

Very nice Scott!
i miss building stuff like this! makes me want to tear my 2nd floor off and build on
a whole full 2nd story!
but it is just the 2 of us, sort of hard to justify.......

 

[ace10]

I see a couple of turtle vents up there, if that's the only vents, there is going be a lot more problems

Could be. I was thinking those were possibly for kitchen/bath exhausts.

Nothing on the ridge. Nothing on the soffit. Maybe something on the gable end?

I dunno. Doesn't look good to me.

 

[canadiantoy]

CT-
Where is the venting for the attic of that gabled roof?

.

You are correct, the initial design didn't provide enough venting. A ridge vent was added by the builder at the same time as the spray foam was installed. A ridge vent was also installed on top of the two dormers.

CT

 

[scott_vt]

Very nice Scott!
i miss building stuff like this! makes me want to tear my 2nd floor off and build on
a whole full 2nd story!
but it is just the 2 of us, sort of hard to justify.......

Good Evening Dutch,
Thanks, yep this was the last big project up here ! Did the barn in 2010, so this is it. We are in the same boat, just the two of us now with an occasional guest !

Hope Tim gets his problems straightened out !

 

[timswi]

Thanks guys...Mine is also a modular cape like Duch but the 2x's are 2x6 and up except for the 6' knee walls which are 2x4. There is no excess bracing as the original lumber from all appearances looks stick built beyond the hinging points which aren't very obvious unless you know what you're looking for...

Anyway, radio silence-still--from the foam contractor and supplier...Done with them. Going to put airflow baffles in every bay then follow with fiberglass..the Rock stuff suggested is only available as a sound deadener around here. Will go as high an R as possible for the spaces I'm working in. Should have the HVAC done this weekend, run some cable/phone/speaker wires and it's insulation time.

The primary reason for the spray foam was my daughters comfort, not resale or any other potential benefit. I'm going to do the best I can with what I have to work with.

 

[ace10]

You are correct, the initial design didn't provide enough venting. A ridge vent was added by the builder at the same time as the spray foam was installed. A ridge vent was also installed on top of the two dormers.

CT

Was a soffit vent installed?

 

[aczlan]

i have a modular built cape, and prior owner's finished the "attic" into 2 bedrooms and a bathroom.
there is a flat ceiling in the rooms, with unfinished cold space above.
differences here that i can point out is the modular came with the main level ceiling insulated and
plywood on top of the joists to create the 2nd floor. I have done some remodeling of that bathroom
and noticed it was insulated well. it's above this level the problems start. the roof system
of these modulars comes folded down for transport, and i believe they hinge the top portion up into place as they set
the sections together. this roof section seems to be made with 2x4's with a lot of extra cross bracing etc.
in comes somebody to build rooms, and knee walls are built 4-5' in from the eaves. sheetrock was put on
the bottom of the 2x4 rafters for the sloped portion of the ceiling . bat insulation on the top of the ceiling, in the roof rafters between the
sheet rock and plywood on the sloped ceiling, and then bat insulation in between the knee wall studs.
cold cold cold up there, as i'm sure it was very shoddy work to begin with, but by insulating the sloped ceiling
it cut off airflow from the soffit vents up to the attic ridge vent. so the soffits and behind the knee walls is cold air
with no place to go, and i'm sure it comes thru the wall. in the attic all insulation ends up above that ceiling,
of which i posted a picture. (first thing we did after closing was have all that insulation re-positioned as in
the picture it's quite scattered!)
i have pondered the same question. tear off the sheetrock, spray foam it all and close off the eaves,
or, build baffles and then spray foam, but with only a 2x4 to work with by the time we install a baffle
it doesn't leave much room for insulation. then i'm not 100% sure that those areas on the sloped
ceiling that are sheetrocked don't have a cross brace in like there are above the ceiling.
currently we have those rooms closed off, nobody lives with us, except for when we have visitors.
View attachment 395685

We have the same problem, but our house was stick built and the room in question is the master bedroom...

Aaron Z

 

[canadiantoy]

Was a soffit vent installed?

Yes, 100% of the soffits are vented