Rim / band joist insulation - Page 7

Ryland · 12-18-11, 03:19 PM

Quote:

Originally Posted by warmwxrules

Will do... I'm going to rip out the face insulation in there and caulk. There is no way I'm messing with foam spray.

Why couldn't a person just close off the "sill boxes" with plywood and fill them with cellulose? Am I nuts?

It would be more work, but it would also do a good job of insulating them, just make sure that any big holes or cracks are filled so you don't get rodents getting in, the cellulose should do an ok job of blocking off small drafts, a hand full of small cans of foam (wear gloves and long sleeves!) does a great job of sealing and might be easier then caulk.

hotwire · 12-18-11, 05:13 PM

Quote:

Originally Posted by warmwxrules

Will do... I'm going to rip out the face insulation in there and caulk. There is no way I'm messing with foam spray.

Why couldn't a person just close off the "sill boxes" with plywood and fill them with cellulose? Am I nuts?

I've seen the rim joist closed off with EPS foam and then dense packed with cellulose.

The picture is from Mike Smith's excellent thread on building an Energy Star home, here is a link.http://forums.delphiforums.com/break...d&u=1890487342

S-F · 12-18-11, 08:53 PM

Go ahead and fill them with cellulose. Good idea. But it isn't an air barrier. Your cellulose in there will get wind washed. You need to fully seal up that entire area first. And don't bother with caulk. Use 1 part foam. You will save yourself hours of work and a small fortune in caulk.

petehouk · 12-14-12, 07:09 PM

Hi everybody. I like the video on the first page of this post. I was thinking about doing that to my band joist.

Except for one thing. My house appears to have two boards at the band joist. They are separated by a few inches. So if I insulate the inner band joist, it will keep the cold air out of my basement. But the inch or two of floor above the cavity between these two boards will still be cold.

I have noticed that the baseboards along the exterior walls of my house are very cold--sometimes they get frosty in the closets. I am thinking that it's because of the cold air trapped in this cavity. I would really like to fix that.

I was thinking that a professional could pump some of that expanding foam into the cavity. But is there a way to do this myself?

Thanks!

S-F · 12-14-12, 07:16 PM

Quote:

Originally Posted by petehouk

Hi everybody. I like the video on the first page of this post. I was thinking about doing that to my band joist.

Except for one thing. My house appears to have two boards at the band joist. They are separated by a few inches. So if I insulate the inner band joist, it will keep the cold air out of my basement. But the inch or two of floor above the cavity between these two boards will still be cold.

I have noticed that the baseboards along the exterior walls of my house are very cold--sometimes they get frosty in the closets. I am thinking that it's because of the cold air trapped in this cavity. I would really like to fix that.

I was thinking that a professional could pump some of that expanding foam into the cavity. But is there a way to do this myself?

Thanks!

Welcome to the site fellow Ecorenovator!
Glad to have you on board.

If I am not mistaken the second boards you are talking about are joists which are close to the rim joist..... ? I have this in my house also on the north (read coldest) wall. I just squirted the spray foam up there. it was a PITA because I had already framed my basement and the top plates for the basement walls were an obstruction. But you can do it.

petehouk · 12-15-12, 07:47 AM

Right now I am working on the wall that is perpendicular to the floor joists. It's not the first floor joist that is in the way.

It appears that there are two joists on top of the foundation wall. I attached a picture. The interior joist is 4" away from the inside edge of the foundation wall. The exterior joist is flush with the exterior edge of the foundation wall. The wall is 10" thick, so that leaves a 3" wide cavity. (10"-1.5"-1.5"-4"=3")

There are several windows along the top of the foundation wall. They stick up about 4" above the top of the foundation wall. The band joists are notched out to fit around the top 4" of the window frame. I am assuming that the builder doubled up the joists because of those notches.

S-F · 12-15-12, 09:09 AM

Usually this occurs because the framers kept the 16" or 24" OC convention and the last joist, spaced per convention, was less than 16" or so from the rim. If the joists are sandwiched together then I could see it being for strength. The ways people make houses baffles me.

petehouk · 12-15-12, 09:54 AM

S-F: I agree that would be the case on the wall that is parallel to the floor joists.

The wall that I am working on is on perpendicular to the floor joists.

S-F · 12-15-12, 10:01 AM

And there's a space between them? Well, OK. None the less you can spray foam up in there.

gt390 · 01-21-13, 01:33 PM

Hope it's alright to bump an old thread, but it's on topic. I wanted to share some of my results.

I'm remodeling my basement which will expose the rim joists. It's common in my area for 70-80's houses to have the joists poured right into the foundation wall so there is only about 1" of space above the concrete to the bottom of the floor above. Leaves not a lot of space for insulating but they did stuff some batting in there. For some background, it's really cold here in winter. Nighttime temperatures have been hitting -30C (-22F). Daytime temperatures in the -20s.

I was able to experiment in my furnace room as it doesn't have a finished ceiling so I have full access to the rim joists. I just got a bottle of large gap spray foam from Home Depot, pulled out the old batting and foamed up in the gap as much as I could. I was able to do about 4 joist spaces. I did not put anything on the face of the concrete wall (yet).

Using my temperature gun, the temperature on the floor in the room above where the rim joists were not foamed was about 3-4C cooler compared to those that were foamed. This is seriously significant. Areas that were foamed was about 18-19C with areas that were not around 14-16C.

I was considering whether to go to the trouble of opening up the ceiling in the rooms I wasn't necessarily going to touch with the reno in the basement, but seeing how significant this is and they are below my kids (on the way) room I will probably go ahead with it.

Next to order the HT-300 gun which was recommended in another thread and open up the ceilings in the other areas and get foaming.

12-15-12, 07:47 AM	#66
petehouk Lurking Renovator Join Date: Dec 2012 Location: Ann Arbor, MI Posts: 13 Thanks: 0 Thanked 0 Times in 0 Posts	Right now I am working on the wall that is perpendicular to the floor joists. It's not the first floor joist that is in the way. It appears that there are two joists on top of the foundation wall. I attached a picture. The interior joist is 4" away from the inside edge of the foundation wall. The exterior joist is flush with the exterior edge of the foundation wall. The wall is 10" thick, so that leaves a 3" wide cavity. (10"-1.5"-1.5"-4"=3") There are several windows along the top of the foundation wall. They stick up about 4" above the top of the foundation wall. The band joists are notched out to fit around the top 4" of the window frame. I am assuming that the builder doubled up the joists because of those notches. Attached Thumbnails

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12-18-11, 08:53 PM	#63
S-F You Ain't Me Join Date: Nov 2009 Location: Northampton MA Posts: 662 Thanks: 6 Thanked 71 Times in 58 Posts	Go ahead and fill them with cellulose. Good idea. But it isn't an air barrier. Your cellulose in there will get wind washed. You need to fully seal up that entire area first. And don't bother with caulk. Use 1 part foam. You will save yourself hours of work and a small fortune in caulk.

12-14-12, 07:09 PM	#64
petehouk Lurking Renovator Join Date: Dec 2012 Location: Ann Arbor, MI Posts: 13 Thanks: 0 Thanked 0 Times in 0 Posts	Hi everybody. I like the video on the first page of this post. I was thinking about doing that to my band joist. Except for one thing. My house appears to have two boards at the band joist. They are separated by a few inches. So if I insulate the inner band joist, it will keep the cold air out of my basement. But the inch or two of floor above the cavity between these two boards will still be cold. I have noticed that the baseboards along the exterior walls of my house are very cold--sometimes they get frosty in the closets. I am thinking that it's because of the cold air trapped in this cavity. I would really like to fix that. I was thinking that a professional could pump some of that expanding foam into the cavity. But is there a way to do this myself? Thanks!

12-15-12, 09:54 AM	#68
petehouk Lurking Renovator Join Date: Dec 2012 Location: Ann Arbor, MI Posts: 13 Thanks: 0 Thanked 0 Times in 0 Posts	S-F: I agree that would be the case on the wall that is parallel to the floor joists. The wall that I am working on is on perpendicular to the floor joists.

01-21-13, 01:33 PM	#70
gt390 Lurking Renovator Join Date: Dec 2012 Location: Canada Posts: 7 Thanks: 0 Thanked 1 Time in 1 Post	Hope it's alright to bump an old thread, but it's on topic. I wanted to share some of my results. I'm remodeling my basement which will expose the rim joists. It's common in my area for 70-80's houses to have the joists poured right into the foundation wall so there is only about 1" of space above the concrete to the bottom of the floor above. Leaves not a lot of space for insulating but they did stuff some batting in there. For some background, it's really cold here in winter. Nighttime temperatures have been hitting -30C (-22F). Daytime temperatures in the -20s. I was able to experiment in my furnace room as it doesn't have a finished ceiling so I have full access to the rim joists. I just got a bottle of large gap spray foam from Home Depot, pulled out the old batting and foamed up in the gap as much as I could. I was able to do about 4 joist spaces. I did not put anything on the face of the concrete wall (yet). Using my temperature gun, the temperature on the floor in the room above where the rim joists were not foamed was about 3-4C cooler compared to those that were foamed. This is seriously significant. Areas that were foamed was about 18-19C with areas that were not around 14-16C. I was considering whether to go to the trouble of opening up the ceiling in the rooms I wasn't necessarily going to touch with the reno in the basement, but seeing how significant this is and they are below my kids (on the way) room I will probably go ahead with it. Next to order the HT-300 gun which was recommended in another thread and open up the ceilings in the other areas and get foaming.