Spray Foam Insulation

[jgedmond]

My heater went out sometime last night while the low was 26F and the daytime high was about 58F. My house stayed above 68F all night and day. Very pleased with the insulating qualities of the spray foamed attic and blown in fiberglass walls. I know that these are wimpy temperatures for you northerners, but if you can't get a new igniter for your LPG furnace for a few days, it makes all the difference! I didn't feel the need to mess with the forced air fireplace, but I will if I need to.

 

[EddieWalker]

How thick is your spray foam and is it closed cell or open cell?

 

[jgedmond]

The spray foam is ~6" thick under the roof deck and on false walls created to block off uninsulated areas (garage attic, over porch cavities). I am pretty sure it is open cell.

The walls 2 x 4 studs with loose glass fiber blown in. The roof is metal and mostly hipped with two large gables one over the uninsulated garage and the other over the front porch.

 

[Toyboy]

Up here in N WI where I am, the spray foam is getting more popular. Cost wise, it's over double fiberglass insulation but we build with 2x6 outside walls. My house was built in 2001 right before spray foam caught on. If I had to do it again I'd foam it.

 

[jgedmond]

Up here in N WI where I am, the spray foam is getting more popular. Cost wise, it's over double fiberglass insulation but we build with 2x6 outside walls. My house was built in 2001 right before spray foam caught on. If I had to do it again I'd foam it.

I agree, some comparisons from our previous tract built home (1997) in NW Houston to our current custom home about 100 miles north in East TX (2016):

Our new home is ~10% more square feet with higher ceilings (10' - 12'). We now have LPG heat and an electric coop (vs. natural gas and competitive electric suppliers), so our energy costs per BTU and kW-hr are significantly higher. Despite that our peak energy month (August) bills are ~30% lower with the thermostat set lower.

Some mitigating factors for our rural home are metal roof (radiant barrier), more porch overhangs and smarter window placement, "Tyvek" type wrap and window tape, more shade trees, and better orientation of the house to sun exposure. It all works together, but I believe that the spray foam and blown in walls are big factors.

FYI, we did not do foam in the walls to allow more breathability for the structure. With all foam you are basically living in a cooler, so moisture retention becomes a real problem especially in the humid region that we live in.

 

[kenmac]

Last couple of homes around me have used spray foam attic and walls. I can see the advantages of foam vs regular insulation.
The foam will fill all the cracks.
Down side is. If you need to do any wiring /plumbing repairs, it make be more difficult with foam walls

 

[oosik]

I had a friend whose DIY theory was - "If a little is good, a lot is better". His DIY foaming project blew the sheetrock & studs off the walls in his basement. He was lucky. The studs were attached to a poured concrete basement wall. The expanding foam blew the sheetrock & many studs off the concrete wall. If it were an above ground stud wall it could have "blown" outwards. Herb was a good guy though.

 

[AllByteNoBark]

We had spray foam in our last house and sprayed the one we just built a couple of years ago also. It does cost more than fiberglass but is well worth it. We have 6 inch walls with around 5 inches of open cell foam in them. The roofline is foamed and is at least 8 inches and probably closer to 10. Yes it is like living in a large cooler. We have never had issues with moisture even though we live in a very humid climate now. The house is tight but we are in and out a lot and did not put an air exchanger in the house we are in now. We had two of them in the previous house and never used them. Some will argue that you should only use closed cell, others only open cell. We had extremely good luck with the open cell in the last house and when I spoke to the foam guys in our area they recommended the open cell. You want to make sure to use a good vapor barrier with the open cell as it will not act as a vapor barrier like the closed cell does.

Also what you use for HVAC comes into play. We keep the house cool but have a multi speed A/C that runs mainly in the low speed all summer to control humidity while cooling. It is easy to make the house feel like a refrigerator if you don't have an HVAC system that can be used to control the humidity as well as temp.

We have been very happy with the foam and would do it again.

 

[3Ts]

Our house is also spray foam with 2x6 exterior studs. We have the open cell and probably a vapor barrier on the walls and none on the roof. Sizing HVAC is very important with this. To big and it won't run long enough to dehumidify. They were to put in a 3 ton unit, they put in 4 ton. However, we also have a whole house dehumidifier and it runs in the spring and fall. The dehuidifier is independent of the AC & heater and is well worth the extra expense.

This is our second house with spray foam and I'd do it again.

 

[jgedmond]

Our house is also spray foam with 2x6 exterior studs. We have the open cell and probably a vapor barrier on the walls and none on the roof. Sizing HVAC is very important with this. To big and it won't run long enough to dehumidify. They were to put in a 3 ton unit, they put in 4 ton. However, we also have a whole house dehumidifier and it runs in the spring and fall. The dehuidifier is independent of the AC & heater and is well worth the extra expense.

This is our second house with spray foam and I'd do it again.

Good points. Our builder said that 5 ton was enough, but I was skeptical based on our smaller previous home with 5 ton that ran continuously in the summer. I thought that we would need to zone the larger new home to get more tons. It turns out that the 5 ton runs enough to keep humidity at 40 - 50% and while maintaining the temperature where we like it at 72F.

 

[Grumpycat]

Investigating all options for home I will have built this coming year.

Am favoring ICF construction. Spray foam is an option for the roof.

Have concerns about fire codes. That some spray foam material is not as fireproof as fiberglass wool. That all require another layer to slow the progress of fire. That usually 1/2" gypsum board serves but that doesn't apply to foam sprayed on the underside of the roof.

If you have seen YouTube videos of spray foam being applied you wouldn't dare try to spray foam into a finished wall. Foam expands for seconds after being sprayed so it would have to push up or out. Is most commonly applied between the joists and if you want the void filled then they come back later and shave the excess off.

A very interesting concept for a barndominium, a house built inside a metal building, was to build a 2x4 stud wall a small distance from the metal outer wall then fill that void with spray foam partially into the 2x4 space. Eliminates most of the heat/cooling loss through the wood studs. Eliminates the problem of an uneven foam inner surface. Leaves room between the studs for wiring.

Much the same fire concerns for ICF.

 

[Corkpuller]

How close are you to T Bend?

We are looking for a Builder for a shop and home.

 

[IXLR8]

If you are building, here is something new to consider, insulated 2x6 studs. Wood only has an R value of 1/inch. You may have R19 in the walls, but with 10% of your wall being studs with only an R value of 6, the overall wall R value is about 12. You need to do something to break the thermal bridge that the 2x6 creates. I have no affiliation with this company, I just stumbled upon them a few weeks ago when researching building materials.
Tstud

 

[3Ts]

Investigating all options for home I will have built this coming year.

Am favoring ICF construction. Spray foam is an option for the roof.

Have concerns about fire codes. That some spray foam material is not as fireproof as fiberglass wool. That all require another layer to slow the progress of fire. That usually 1/2" gypsum board serves but that doesn't apply to foam sprayed on the underside of the roof.

If you have seen YouTube videos of spray foam being applied you wouldn't dare try to spray foam into a finished wall. Foam expands for seconds after being sprayed so it would have to push up or out. Is most commonly applied between the joists and if you want the void filled then they come back later and shave the excess off.

A very interesting concept for a barndominium, a house built inside a metal building, was to build a 2x4 stud wall a small distance from the metal outer wall then fill that void with spray foam partially into the 2x4 space. Eliminates most of the heat/cooling loss through the wood studs. Eliminates the problem of an uneven foam inner surface. Leaves room between the studs for wiring.

Much the same fire concerns for ICF.

If you have exposed spray foam and are concerned about fire, look into intumescent paint as a possible solution.
Intumescent Paint, Fireproofing, and Firestopping - archtoolbox.com

 

[EddieWalker]

If you are building, here is something new to consider, insulated 2x6 studs. Wood only has an R value of 1/inch. You may have R19 in the walls, but with 10% of your wall being studs with only an R value of 6, the overall wall R value is about 12. You need to do something to break the thermal bridge that the 2x6 creates. I have no affiliation with this company, I just stumbled upon them a few weeks ago when researching building materials.
Tstud

Insulation is one of those things that it's real easy to get caught up in a lot of little things that wont actually provide any noticeable improvement in a house that can cost a lot of money. Wood studs are not even close to being as big an energy loss as windows and doors. You can spend tens of thousands of dollars more on a house improving your windows and doors, and still not see any savings in your energy bill. What is most important on a wall is stopping air flow. If a decent 2 pane window is taped, and the house is wrapped with all the seams taped, just about any type of wall insulation is going to give the same results. The newest trend is to paint the sheathing with a WRB Paint. Zip System is OSB with a WRB already applied that relies on tape being added to the seams. Stopping the wind is where you gain your noticeable results in the walls.

Heat gain and loss is almost exclusively controlled by how well the attic area, or roof, is insulated. This is where foam really shines. Nothing is better then closed cell foam. I would never use open cell and personally think it should be banned from being used in homes. For less money, blown in insulation will give you the same results if you have it applied deep enough to achieve the same R value. It's all about the R value and how much room you have to obtain it. I have 2 feet of blown in Atticat in my house and it's awesome. When I build my shop, I will have a ceiling so I can do the same in there. When I add on to my house, I will have a vaulted exposed beam ceiling with no room for blown in insulation, so I will use closed cell foam for there.

Those are the basics. You can tweek the basics and obtain some small results, but overall, there isn't very much else that you can do that will provide a noticeable improvement over what you get with a air tight wall and R60 ceiling.

 

[ruffdog]

Is there any issues with foam off-gassing and people breathing the fumes? I'm sure the attic would be ok but don't know about walls. Some people are very susceptible to certain fumes.

Does Spray Foam Insulation Off-Gas Poisonous Fumes? - GreenBuildingAdvisor

Potential Chemical Exposures From Spray Polyurethane Foam | Safer Choice | US EPA

 

[jgedmond]

Insulation is one of those things that it's real easy to get caught up in a lot of little things that wont actually provide any noticeable improvement in a house that can cost a lot of money. Wood studs are not even close to being as big an energy loss as windows and doors. You can spend tens of thousands of dollars more on a house improving your windows and doors, and still not see any savings in your energy bill. What is most important on a wall is stopping air flow. If a decent 2 pane window is taped, and the house is wrapped with all the seams taped, just about any type of wall insulation is going to give the same results. The newest trend is to paint the sheathing with a WRB Paint. Zip System is OSB with a WRB already applied that relies on tape being added to the seams. Stopping the wind is where you gain your noticeable results in the walls.

Heat gain and loss is almost exclusively controlled by how well the attic area, or roof, is insulated. This is where foam really shines. Nothing is better then closed cell foam. I would never use open cell and personally think it should be banned from being used in homes. For less money, blown in insulation will give you the same results if you have it applied deep enough to achieve the same R value. It's all about the R value and how much room you have to obtain it. I have 2 feet of blown in Atticat in my house and it's awesome. When I build my shop, I will have a ceiling so I can do the same in there. When I add on to my house, I will have a vaulted exposed beam ceiling with no room for blown in insulation, so I will use closed cell foam for there.

Those are the basics. You can tweek the basics and obtain some small results, but overall, there isn't very much else that you can do that will provide a noticeable improvement over what you get with a air tight wall and R60 ceiling.

I much prefer my new 85 F attic with foam under the roof to my old 140 F attic with that messy, dusty blown in stuff underfoot. We use our attic for light storage and it is much more comfortable to store or retrieve something, reset the router, work on A/C etc.

 

[EddieWalker]

I've read some interesting articles on the advantage of doing the full house envelope with spray foam compared to traditional insulation in the attic area. One of the big advantages are not having any roof vents which makes a huge difference in areas that are prone to fire. It does create more area to condition, which means a bigger HVAC system and more money to run the bigger unit, but that's probably not as big as expense as the cost of the spray foam and how long it takes to make up that difference when comparing it to R60 of something like AttiCat blown in insulation.

To deal with higher temps in the attic, I make sure nothing is installed in the attic. HVAC is in a closet that anybody can get to 24/7 no matter how old they are. Same thing with storage. It goes into a shed, barn, shipping container or some other building that is accessable 24/7 by anybody of any age. I've made a lot of money fixing damage to homes from storing stuff in an attic that was more weight then the rafters where able to support.

AttiCat isn't dusty. In fact, it's so nice to work with that you don't even need a mask when spraying it!!!

 

[jgedmond]

I've read some interesting articles on the advantage of doing the full house envelope with spray foam compared to traditional insulation in the attic area. One of the big advantages are not having any roof vents which makes a huge difference in areas that are prone to fire. It does create more area to condition, which means a bigger HVAC system and more money to run the bigger unit, but that's probably not as big as expense as the cost of the spray foam and how long it takes to make up that difference when comparing it to R60 of something like AttiCat blown in insulation.

To deal with higher temps in the attic, I make sure nothing is installed in the attic. HVAC is in a closet that anybody can get to 24/7 no matter how old they are. Same thing with storage. It goes into a shed, barn, shipping container or some other building that is accessable 24/7 by anybody of any age. I've made a lot of money fixing damage to homes from storing stuff in an attic that was more weight then the rafters where able to support.

AttiCat isn't dusty. In fact, it's so nice to work with that you don't even need a mask when spraying it!!!

I am not sure if you have basements in Tyler, but if not, you have stuff in your attic that might need attention at some point (electrical, plumbing, gas lines, vent fan piping, etc) or you may need to access the attic to make improvements / repairs to ceiling mounted fixtures. So, I do not think that staying out of the attic is a viable way to "deal with attic temperatures" although it will minimize your exposure to the hot attic.

The Attic Cat site shows the installers wearing masks, I know that might be CYA, but still it is apparently recommended. My concern was with fibers pieces floating around in the attic air after installation when I may be in the attic.

As to size of the HVAC unit, my new home is 10% more square feet with average taller ceilings and larger attic volume (steeper average roof pitch). With the same size HVAC unit, run times and costs are much lower despite cooling that larger volume of air to a lower temperature.

Roof decking moisture issues seem to relate to how well the attic is sealed from external moisture intrusion (did the installers do a good job identifying and covering the house envelope) and having sufficient attic air humidity control (attic supply and return if codes allow).

Think that I am going to put a humidity monitor in my attic to keep an eye on that.

Will Open-Cell Spray Foam Insulation Really Rot Your Roof?

 

[JamesHW]

We entertained spray foam for the uninsulated attic(s) on our 150 year old house and it’s 1920’s addition (built onto an original bump out in the back). As I have developed a fairly serious chemical sensitivity we have remained reticent in pulling the trigger. Speaking with a couple of experienced installers they told me the horror stories of improperly cured foam off gassing an odor long after drying were a result of either temps out of optimum range, either too hot or cold and/or improperly mixed ingredients of the foam. So going with a reputable installer is important. Once installed, removing a botched job would be a nightmare and could chance rendering our home unlivable, at least for me.

Then we remembered being pitched SIP panels for a barn build we were planning and realized these structural panels would be perfect installed over the original roof. Concern over it creating a too thick roof, we remembered that when we reattached some steel roofing that needed securing we found thousands of cut nails sticking up from the roof boards that indicated the roof originally had wood shake shingles that undoubtedly would have presented a much thicker profile than the corrugated roof panels have, alleviating any concerns over esthetics. Because the panels are made under controlled conditions in a factory. So the structural panels give us the insulating properties of closed cell foam w/o any of the possible off-gassing hazards, at least for our roof. I like the Ray-Core panels