Injectable Foam Insulation

[Jeff]

My attached garage/partial/shared workshop is 28'x26' with no insulation. I'm thinking about having injectable insulation installed, but don't have a clue.

Both walls are 28'x9' framed with 2x4s @16"oc. Ceiling is 28'x26' framed with 2x10s @16"oc (have plywood flooring overlay up there as well).

What do you all think about injectable foam insulation? Any experience out there? Pros and cons?
Other considerations like the wiring? I have an overhead propane industrial heating unit, but with this cold winter it's working overtime during the day, but off at night. Would the insulation make it ungodly hot in the summer months (it's already hot enough then)?

I'm looking for potential contractors in the Raleigh/Durham/Hillsborough/Roxboro area, but will consider others outside of that.

Thanks in advance.

 

[Glennbear]

Our own Scott Smith has had extensive experience with injectable foam insulation. He will probably chime in but in case he does not he would be the man to contact. :wsmile:

 

[jhreed]

I have an interest in this as well. My house is 70 years old and the walls are plaster. the insulation was rock wool and I am sure it has settled. My utilities are about $500.00 in the coldest and hotest months.

 

[mkepke]

If money is no object, have closed cell foam sprayed in.

If money is an object, get some quotes, blanch and then install batt fiberglass in the walls and batts or blown cellulose in the ceiling.

Seriously, the only thing preventing everyone from using foam is the price..about 3-4x the cost of fiberglass.

BTW yes, installing insulation will keep the heat *in* during the summer months. Ideally you'd have some way to vent the garage in the summer.

-Mark

 

[James Davis]

Insulation will keep the heat out as well. If you do insulate, I feel the money spent on the ceiling will be at least as beneficial as the walls. The ceiling will keep the heat from rising out in winter and will keep the heat generated in the attic up there.

These are just observations from my experience, not grounded in fact.

James

 

[NCPete]

how about cellulose blown in the ceiling, and the walls?

much less expensive than the foam, and it's what we had done in the 100 year old farm house I grew up in in northern NY. First insulation that house had, except for just enough in the ceiling to be maybe an R9, we put in during the summer of 1977. Big old van pulled up to the building, holes were drilled in various places to fill the walls, and another line was run to the attic to dump buckets of cellulose up there. Good timing too, as the next winter had record snowfall - which reduced our ability to restock the firewood supply, and the winter of 78-79 saw a fair stretch at below -40*

 

[scsmith42]

Jeff, there are two different approaches to foam insulation. Injectible is used when you have some type of interior wall installed (sheetrock, plywood, etc) that covers the studs. Spray foam is used when the studs (and rafters) are visible.

Without question, foam insulation - properly installed - is the best insulation available today. Closed cell has a slightly higher insulation value than open cell; however open cell is superior for noise dampening applications.

You will spend 2X to 3X for foam insulation as compared with other options, but in the long run the savings will probably pay for the difference.

In the attic, spray foam is typically applied directly to the underside of the roof. It should not make it "ungodly hot", if anything it should keep things significantly cooler.

Allied Spray Foam is a great company to work with in the Triangle. If you're interested, I can send you their contact number via PM. They do not do "injectible", just spray foam, but they can recommend someone for injectible if you want to go that route.

 

[woodworker2000]

What is the R-value per inch for closed cell foam insulation? Scott, you mentioned that it is applied directly to the undeside of the roof in an attic. If that is the case, how does that affect the venting (I have soffit and ridge vents)? Thanks.

 

[Kicbak]

I got closed cell foam spray in my house a few years ago. For 2 1/2 inches of foam it has the same as 6" of fiberglass, R-19. The stuff really is amazing, power bills are low, no drafts and really good at sound proofing.

Wes

 

[Ray Martin]

I have an interest in this as well. My house is 70 years old and the walls are plaster. the insulation was rock wool and I am sure it has settled. My utilities are about $500.00 in the coldest and hotest months.

James,

I was in a rather old house previous to my present home, and I do remember utility bill being in the ridiculous range. If you have not yet done any work on the energy conservation front yet, I'd suggest an energy audit. There's some information from the government at http://www.energysavers.gov/your_home/energy_audits/index.cfm/mytopic=11160
Maybe some of our members have had audits done. Some utility companies do audits too.

 

[Mike Gilley]

Jeff,
Check out this previous post from November, on Mike Wood's experience with going the sprayed foam insulation path.

http://www.ncwoodworker.net/forums/f81/insulating-roof-26933/

 

[scsmith42]

What is the R-value per inch for closed cell foam insulation? Scott, you mentioned that it is applied directly to the undeside of the roof in an attic. If that is the case, how does that affect the venting (I have soffit and ridge vents)? Thanks.

Christopher, the r-value is misleading, because spray foam seals off 100% of the drafts through the wall, and that is not something that R value takes into account. More good info on the link that Mike provided.

Re the vents, there are two choices - either put in rigid foam panels to maintain the venting up to the ridge, or eliminate them. The installers that I have worked with recommended eliminating the vents, which is what I've done on all of my installations. Works like a champ.

 

[woodworker2000]

Scott-
Thanks for the response. I went to the ASF site and read the information they presented on R-value being a misleading number but I'm still wondering how you get around code requirements (and inspectors). Doesn't code around here (Raleigh) require R-30 in ceilings/roofs along with roof venting?

 

[Gofor]

Christopher, the r-value is misleading, because spray foam seals off 100% of the drafts through the wall, and that is not something that R value takes into account. More good info on the link that Mike provided.

Re the vents, there are two choices - either put in rigid foam panels to maintain the venting up to the ridge, or eliminate them. The installers that I have worked with recommended eliminating the vents, which is what I've done on all of my installations. Works like a champ.

IIRC, the main objective of ridge vents, roof vents is to save the roof from excess heat on the underside, which will greatly increase the rate of shingle deterioration. A roof with dark shingles can build up temps up to 160+ degrees between the rafters if not ventilated, and it just sits there and cooks the roofing. The insulation on the ceiling (or around the walls/ceiling in an attic room) is to insulate the living space. The spray foam directly applied to the roof sheathing prevents the excessive heat build-up from occurring, there-by eliminating the need for the vents, as well as reducing attic temps increasing the effectiveness of the ceiling insulation.

Go

 

[Jeff]

Jeff, there are two different approaches to foam insulation. Injectible is used when you have some type of interior wall installed (sheetrock, plywood, etc) that covers the studs. Spray foam is used when the studs (and rafters) are visible.

Without question, foam insulation - properly installed - is the best insulation available today. Closed cell has a slightly higher insulation value than open cell; however open cell is superior for noise dampening applications.

You will spend 2X to 3X for foam insulation as compared with other options, but in the long run the savings will probably pay for the difference.

In the attic, spray foam is typically applied directly to the underside of the roof. It should not make it "ungodly hot", if anything it should keep things significantly cooler.

Allied Spray Foam is a great company to work with in the Triangle. If you're interested, I can send you their contact number via PM. They do not do "injectible", just spray foam, but they can recommend someone for injectible if you want to go that route.

Alamance Insulation sent a quote for spray foam insulation (they don't do injectable) for my project. About $4800-5600 for my 28'x26' garage (2 walls @ 28'x9', ceiling @ 28'x26'). Yikes! Blown in fiberglass is about $1.25/sq.ft. so this is about 3.5x higher.

My problem is that the walls and ceiling are covered with sheetrock so injectable (even more expensive?) or blown could work. I could consider blown fiberglass for the walls and spray foam for the ceiling rafters. :icon_scra

The garage is just that-a garage, so I'm not looking for a second mortgage after 21 years of making do as is in summer and winter! Nonetheless, its been an informative exercise.

Thanks for everyone's input and an interesting discussion thread for all of us.

 

[mike_wood]

I had my 25'X25'X8' (10' ceiling as the walls are on a 2' brick wall - required by my HOA) shop and roof insulated with closed foam insulation. It was $3k. I went for it as there is a 30% tax credit and in the long run will save money. For example, I put in a split HVAC unit (110v, 3A) that was rated as too small for my shop. My HVAC installer didn't want to do it. I keep the thermostat set on 60 degrees all the time and it stays comfortably warm even on these miserably cold nights. It barely runs most of the time. As far as insulation it is the best I have ever experienced. My shop is 1.5 story and the upper storage area stays ~55 degrees. The ceiling is uninsulated. I have a painted concrete floor.

When I was considering the foam insulation I was concerned about moisture and it remains a concern. On cold days the doors (I have a single and double door) and windows are coated, and I mean coated (running down the glass), with condensation. I have emailed Allied Spray with my concerns but they have yet to reply. That was 2-3 weeks ago. I guess I will have to keep bugging them for a response. My understanding was that moisture moves through open foam insulation but it seems to me something is not working right. My shop is not complete so I don't have any wood stored in it and since it has been cold it has not been opened to allow moisture in. Not sure where the moisture is coming from. At first I thought it was the concrete floor but after a few months I don't think that can be it. My last shop I put in fiberglass insulation and a semipermeable vapor barrier. Had not one problem and the shop had way more ambient moisture since part of it was my basement.

If it wasn't for the moisture problem I would be quite happy recommending it to anyone. However, until I get this sorted out I am reluctant. I will post if I get to the bottom of this problem.

 

[Gotcha6]

mike_wood Re: Injectable Foam Insulation


Not sure where the moisture is coming from. At first I thought it was the concrete floor but after a few months I don't think that can be it. My last shop I put in fiberglass insulation and a semipermeable vapor barrier. Had not one problem and the shop had way more ambient moisture since part of it was my basement.

Mike, a simple test to determine if the slab is still emitting moisture:

1. Duct tape a 24" x 24" piece of 4 mil or thicker poly to the slab.
2. Wait 16-24 hours. If moisture is present on the underside of the poly, it's coming from the slab. Even painting a floor will not prevent it from evaporating in all cases.

 

[CrealBilly]

Hey Jeff - I read about Superinsulating Aerogels today in Popular Science. I know it's not what your after but is a interesting material if what they say is true...

"you could take a two- or three-bedroom house, insulate it with aerogel, and you could heat the house with a candle. But eventually the house would become too hot."

http://www.popsci.com/technology/article/2010-02/aerogels-hit-consumer-insulation-market

Thanks