# insulation for bonus room over garage



## BrianinNC (Mar 16, 2013)

So to start of i have a 7 yr old house which i bought as new constuction. The bonus room is finished and the 2-door garage is finished. At the time i was traveling for long periods of time so i never took notice of it but when things slowed down i notice the same as most bonus rooms above garage syndrome. very cool in the winter and very hot in the summer. I desided to invesigate and found that they put insulation around the room but that was it. None in the open space and no lower rafter vents. Air is just flowing freely thru the joist. I'm really not trying to tear the ceiling down. I figured i could close of the open floor joist with insulated foan and spray foam it to block air flow, install celulose in the open space and put up some foil backed insulation on the knee walls. What can i do about the angled walls?? Any pointers tips anyone can give me? I'm also in the proccess of insulating the garage doors as well. Most of the stuff i found is where the the room is unfinished or the garage joist are open. Here are some pics .


pic behind the long bonus room wall









start of the insulation on the angled walls










notice the air pocket in the insulation. This is why my feet was so cold this winter


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## Nailbags (Feb 1, 2012)

I would use loose fill in there no need to use spray foam to costly. You want ventlation in there for the roof or your going to have other problems then cold in the winter and hot in the summer. like premature roof failure. there has to be some air movement in the attic space. just use a good loose fill insulation keep the baffels inplace insulate to at least R-48 and you should be good to go!:thumbup:


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## asinsulation (Apr 11, 2011)

you want to allow the air to travel through the ceiling area, do not close it off. If you really want to see a difference there, address the garage ceiling between the bonus room and the garage with densepacked cellulose, and seal off the edges with foamboard and spray foam. then, tack up foamboard or some type of air barrier over the fiberglass that lays vertical on the wall to stop any windlashing, which kills the r-value of fiberglass. If the situation is how I am imagining it from the pictures, that should help alot.


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## BrianinNC (Mar 16, 2013)

Here is another pic so you can kinda understand what i'm talking about. Maybe saying foam was the wrong word to say. i want to block air from going under the bonus room I.E cold floor in side of bonus room. Run vents on the bottom of rafters to move air up to roof vent and some how keep the angled walls more insulated as well. to prevent heat/cool air from escaping or minumize it from getting in.


In this pic i an standing in the bonus room looking to the roof/attic area beside the bonus room












This one is pic looking under bonus room between joist. Don't mind the no insulation there. I moved it for reference


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## Nailbags (Feb 1, 2012)

If those photos are correct yes maybe depends on what is on the other side? siding ect... I would just fill that area the place with the red out line with loose fill and as a after thought I would caulk were the bottom cords of the trusses meet the sheetrock help seal the area better then blow in your loose fill of choice to at least R 48 and you should be a lot happier.


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## BrianinNC (Mar 16, 2013)

I will update my progress on this issue as i go to make sure i'm not going in the wrong direction. This will be a big help.


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## 747 (Feb 11, 2005)

If you plan on using the bonus room. Spray foam. You always spray foam if there is living space above a garage. Yes it more expensive but you will be done with it. 

Example holmes on homes. He has showed up. Living space above garage. There is insulation up there but its still cold. Solution spray foam. No more problems.


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## BrianinNC (Mar 16, 2013)

Well in my case the spray foam i won't need due to the fact even though it is a garage no cars are started in the garage and it's only my classic car in there. i roll the car outside before startup and i only drive it on sunny days. I'm not worries about exhaust fumes entering into the room.


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## asinsulation (Apr 11, 2011)

you have the right idea.


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## BrianinNC (Mar 16, 2013)

So the insulation that's under the bonus room i should replace with cellulose before capping the ends off with foam board if i'm understanding right? Just taking measurements to do a my own cost worksheet to see how much it's going to run. Also i was looking at another post that i must have missed when i was searching and saw that Gary had mentioned Roxul. Is this far better then the usual fiber insulation? Anyone used this in there home can attest to the product? I Noticed at the major hardware stores itt has to be preordered.


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## Nailbags (Feb 1, 2012)

Rockwool or roxul is very good 100% fire proof won't itch won't let vermin live in it and if it gets wet it will dry out. I just got done doing a home with it. It draw backs are it is hard to cut. out side of that it is good stuff. In my opinion.


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## asinsulation (Apr 11, 2011)

roxul is good, but in your application for under the floors it would be difficult. if you want to see a good amount of your results quick, proceed with the air seal around the floor joists. you can always pop a hole for the densepack later and use one part foam to seal it back up. see what results you get from the airseal and if its worth it to go the extra mile with the cellulose.


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## Nailbags (Feb 1, 2012)

From the photos it is open area.


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## BrianinNC (Mar 16, 2013)

Yes. For some odd reason i don't know why they didn't put in a small door there so i'm also going to build one to make the space for storage as well. Funny thing is was before this i had a contractor quote me 2500-3000 bucks to do the job. Kinda was suspect which is why i want to do it on my own now..lol


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## Gary in WA (Mar 11, 2009)

Yes, there should be vents in every rafter bay to rid any moisture/heat from the roof sheathing. Yes, close off below the knee wall and above to prevent wind-washing of the fibrous insulation, yet leaving the baffles open for air movement through them. No* foil-faced *batts on the knee wall; http://www.buildingscience.com/docu...heet-310-vapor-control-layer-recommendations/

Yes, remove the f.g. batts under the room floor, *if *filling with cellulose at a later date. Yes, add an access door (with weather-strip seal and insulation on door back, solid wood has R-1.25 per inch) to the attic for floor storage but do not insulate the floor or rafters as the space is not conditioned, your thermal barrier stops at the knee-wall. 

Add some housewrap to the attic side of the f.g. knee wall frame/insulation batts to prevent wind-washing, degrading your R-value. If no insulation at knee wall now, caulk the drywall/truss vertical member to air seal, also any electrical boxes/wire holes in boxes to ADA the drywall; http://www.buildingscience.com/documents/information-sheets/air-barriers-airtight-drywall-approach/ 

Also, caulk or canned foam the drywall butt joint at the sloped ceiling/vertical wall on attic side to prevent air loss there. Hey, while it's open...lol. Exposed Romex within 6' of the access door requires covering/sandwich between boards to protect from walking on/crushing.

Gary
PS. When you dense-pack, replace the access hole for the tubing with 5/8" Type X drywall (use the cut-out with plywood backers, unless using fire-rated foam in the garage ceiling.


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## asinsulation (Apr 11, 2011)

2500 wouldnt be a terrible price. it is a detailed, time consuming job. the cost of good business


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## BrianinNC (Mar 16, 2013)

He was only adding loose fill. Nothing else


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## Nailbags (Feb 1, 2012)

what is the square footage? you can blow that in yourself.


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## Nailbags (Feb 1, 2012)

asinsulation said:


> 2500 wouldnt be a terrible price. it is a detailed, time consuming job. the cost of good business


that is a horrible price for blown insulation I have homes that are 2,000 to 3,000 square feet all exterior walls bibbed all interior walls batted garage insulated and attic blown for 3 grand. to just do that small room for 2 grand crazy.


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## BrianinNC (Mar 16, 2013)

Well if gary is saying i don't need to do loose fill in the unconditioned space and just under the bonus room then my sq footage is just under 300 sq ft


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## asinsulation (Apr 11, 2011)

well then nailbags, i would imagine they will be out of business in the end or living in an apartment forever...lol

JUST for the loose fill, no, thats not proper. but, for the airseal, and addressing the whole room comprehensively, airsealing, insulation, ensure proper venting and diagnostics to prove results, not a bad deal. Personally, I don't even offer my blow in insulation services in attics if they don't want an airseal with it.


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## Nailbags (Feb 1, 2012)

asinsulation said:


> well then nailbags, i would imagine they will be out of business in the end or living in an apartment forever...lol
> 
> JUST for the loose fill, no, thats not proper. but, for the airseal, and addressing the whole room comprehensively, airsealing, insulation, ensure proper venting and diagnostics to prove results, not a bad deal. Personally, I don't even offer my blow in insulation services in attics if they don't want an airseal with it.


True just blow is not good.


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## Nailbags (Feb 1, 2012)

BrianinNC said:


> Well if gary is saying i don't need to do loose fill in the unconditioned space and just under the bonus room then my sq footage is just under 300 sq ft


If you went with that contractor then you would be paying $6.66 a square foot I would love to see what they quoted you on.


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## asinsulation (Apr 11, 2011)

from one extreme to the other! if I could pull 6.66 a foot on open blow, I would have retired a looooong time ago!


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## Nailbags (Feb 1, 2012)

asinsulation said:


> from one extreme to the other! if I could pull 6.66 a foot on open blow, I would have retired a looooong time ago!


I just took 300sf divided it in to two thousand and you get 6.66 or what the contractor may be charging if it was only blow. but if it is to seal proper vent etc. unless you see the bid you don't get that good of image of what is really bidded. and yes i could live well charging that price.


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## BrianinNC (Mar 16, 2013)

Well I was skeptical because he didnt measure the room or anything. He just threw out a number. We took a pass on his quote.


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## jpc (Dec 11, 2010)

Hey Brian you came to the right place, and gotten the best advice to handle that bonus room, now it's time to make it happen,lol. I'm half way done with mine, I got the outside attic kneewall area finished and soon will start on the other side that connect's to the house side and I can tell ya with just one side done it made a huge differnce. As this bonus room is actually my bedroom I spend alot of time up there.
BIG +1 on caulking/foaming those stud cavities while there still empty. I removed my FG batt's to air seal mine, that sucked lol
Take your time and do it right, and You wont regret it. Good luck with your project and keep us posted on how you make out.


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## BrianinNC (Mar 16, 2013)

Yep. On that note I can't complain. Everyone has given me great advice all around. I'm just crunching some numbers on cost right now.


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## BrianinNC (Mar 16, 2013)

So i had to postpone doing the cellulose due to upcoming surgery this week. Put in the ridge vents already and removing some of the insullation under bonus room. here is another thing i came accross. At least 4 of the spots between the rafter are closed of with (2) 2x6 by 8ft boards. I drilled a hole and its insulated. Should i try and cut these out to remove the insulation that is in there or because it's already closed off just use spray foam to seal it up tight... In the proccess of ordering some Roxul for the knee wall

In this pic you can't tell but the board that looks like it's between the rafter is one long 8ft board.



Also i'm not able to put ridge vent like normal due to another 8 ft 2x6 here.Should i just modify using ridged foam and rafter vent at a different angle??


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## Gary in WA (Mar 11, 2009)

You have some unusual framing going on. No hangers, header at a rake instead of plumb, no shear continuity for the rafters/wall spread connections... do you have a better camera for another pic. from 10' away, facing the framing? Why is sunlight shinning there from *above*? Is this the backside of a dormer window?

Gary


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## BrianinNC (Mar 16, 2013)

Sorry for the non reply. surgery came up and the surgery didn't go as planned so i was down for longer then to be expected. I finially worked on the project this past weekend. So far all the firberglass insulation is out. Blown in cellulose was blown under the floor rafters. I capped off one side of the rafters and just need to do th other side to prevent airflow from going under the bonus room floor. I installed ridge vents along with atticfoil up the room rafters. Spray foamed all cracks but still a little bit more to do. once i put the roxul up can i put atticfoil over it or do i need a vapor barrier?

The insulation on the left was on the walls(notice no R-value is noted)


space in between rafters blocked and sealed



This one is kinda busy here. It's the going up to the angled wall where the top knee wall meets. Installed insulation foam board as well as blocking off the insulation of the angled wall and using foam as well. You can see the vents as well as part of the atticfoil on the roof rafters


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## Nailbags (Feb 1, 2012)

I would love to read what you posted but the stupid side bar for the adds blocked half your post. I hope what you did worked.


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## BrianinNC (Mar 16, 2013)

i'm still working on it. I did one side of insulation and i'll do the rest within the next week or two


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## BrianinNC (Mar 16, 2013)

anyone have any ideas on if I can put up the perforated atticfoil over the roxul or do I need the non-perforated kind to put over it??


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