cellulose vs foam insulation

[heehaw]

i got a quote for insulating a @ 1500 sq ft house: cellulose, @ $2000, but foam was $5000: with the foam, they seal the attic, spray the foam on the rafters and decking, plus the walls of the house, and basicly make a big ice chest out of the house: no insulation goes on the ceiling: so the foam is actually covering a larger area than the cellulose does: 5/12 pitch roof compared to flat ceiling. i know its the best way to go, but poor folk have poor ways: so i guess we'll stick with the cellulose.
heehaw

 

[BobRip]

i got a quote for insulating a @ 1500 sq ft house: cellulose, @ $2000, but foam was $5000: with the foam, they seal the attic, spray the foam on the rafters and decking, plus the walls of the house, and basicly make a big ice chest out of the house: no insulation goes on the ceiling: so the foam is actually covering a larger area than the cellulose does: 5/12 pitch roof compared to flat ceiling. i know its the best way to go, but poor folk have poor ways: so i guess we'll stick with the cellulose.
heehaw

The foam is a much better insulation, so there may be a payback here. It might be better to borrow the money and reduce your heating and cooling bills. Does the foam installer project a payback period? Why not make the foam insulate the same volume as the cellulose? Adding the extra volume will use more foam and more surface area for heat loss. Is you goal to have the high ceiling and spend more money on insulation or save money on insulation and other construction cost? You are comparing two different buildings and see a price difference.
My house has foam walls (insulated concrete forms) and cellulose in the ceiling. The cellulose is 14 inches thick and gives R55 insulation. You might also consider foam in the walls (where there is limited space for insulation) and cellulose in the ceiling where you can use lamianted I beams to get more room for insulation. Try to get an analysis done by an insulation contractor or maybe there is a calculator on line. I hope this helps.

 

[randy41]

i seem to recall hearing about foam insulation creeping and deforming.

 

[ktm250rider]

i was ready to do foam on my house but the cost was triple what the cellulose was, close to 18 grand. If my difference was only 3 grand, Id do it with foam.

 

[hockeypuck]

i seem to recall hearing about foam insulation creeping and deforming.

The only problem I have heard with foam is if it is applied to thickly it will crack especially when it is applied directly to the roof system. I have seen it crack clear through to the plywood on the roof.

 

[heehaw]

this is actually my youngest daughters house: so she makes the decisions, i just get the prices and help find options: if i thought she was going to stay in this house for 10-15 years i might try to talk her into foam: but they framed the house with 2X6's: and 3 inches of foam would leave a heck of a void under the sheetrock: plus as good as cellulose is, with this size house, i don't think she would get a payback in 15 years: i know of several with this size house that used cellulose, and their heating bill runs about $40-50 a month: foam they say will save 25% over cellulose, so thats $10-15 a month, lets say $200 a year: it would take 15 years to get your money back, unless you put that $3k in the bank at 5%, and then you would never catch up..
heehaw

 

[Bill Barrett]

My house is foamed for almost 20 years no cracking or problems. I also insulate with cellulose. In a house that size the pay back is almost not there. Also your house will be more sound proof with cellulose, its green friendly, and dosen't burn. Both are good products.




















b

 

[BobRip]

this is actually my youngest daughters house: so she makes the decisions, i just get the prices and help find options: if i thought she was going to stay in this house for 10-15 years i might try to talk her into foam: but they framed the house with 2X6's: and 3 inches of foam would leave a heck of a void under the sheetrock: plus as good as cellulose is, with this size house, i don't think she would get a payback in 15 years: i know of several with this size house that used cellulose, and their heating bill runs about $40-50 a month: foam they say will save 25% over cellulose, so thats $10-15 a month, lets say $200 a year: it would take 15 years to get your money back, unless you put that $3k in the bank at 5%, and then you would never catch up..
heehaw

With 2 X6 you have more space for the cellulose. In this case I would use the cellulose. That's plenty of insulation.

 

[Diesel-ME]

I'm a big fan of polyurethane foam for the side walls. It seals real tight (no vapor barrier needed) and makes for a quieter house if you happen to live near a busy road. It will pay back over time.

Here in the north where all new homes are built with 2x6 stud walls, folks tend to foam in 3.5-4.5 iinches of foam and leave the rest for an air gap. The 6" studs leave plenty of room behind all your outlet boxes to insulate.

Unless the house in question is going to have cathederal ceilings, in which case foam is the ONLY way to go IMO, I'd use cellulose in the attic as it's real easy to blow in enough of it to get a high R-value.

 

[pat32rf]

Haven't tried the new spray foam yet but back in the 70s when UFFI foam first came to my area we were in a 120yr old brick veneer farmhouse. Walls were plaster.lath,1"pine board,full rough cut 2x4, then air space then brick. The uffi installer was just starting out and very fussy. Gave me a quote, then used twice as much foam as he expected due to the full sized 2x4s and air space. Would only work if humidity was perfect. He stuck to his original quote.
My neighbours also had uffi done later on when it became more cut-throat. They all had problems and removed theirs at great cost. We sold the house 25yrs later with the uffi still intact and WITH NO MEASURABLE DETERIORATION. Our heating costs were the cheapest on the block, even though the house was the oldest and biggest.(we had cellulose in the ceilings).
Fast forward to 2004. We are now in a much smaller, 50yr old house. Just put a 900sq ft addition on the north side. Doubled the area of the house.The addition is 2x4 stick frame with glass batts, covered by 2" of blue styrofoam, joints all sealed and taped, then wrapped in tyvic(building code). Cellulose in attic.The past few winters we have burnt LESS wood than we used to before the addition covered the poorly insulated north wall.
Make sure that you get as high an R value as you can afford, especially in the ceiling and do everything you can to eliminate the drafts, especially around electrical boxes(including the overhead lights). If you are buying your fuel you won't regret it......Look at the various R values versus the costs. One will be more economical for the same R value but you might have to build differently in order to get the space needed for an equivalent R value...

 

[KYErik]

Here's a random cellulose question- when they spray the cellulose onto the wall between studs (before you put up the drywall) what makes it stick there (and not just fall out)?

Is it wet (with water) or is it some special non drying chemical or glue that makes it stick together? I would think that if it was wet (with water) the dampness of it would cause the studs to mold and rot when the drywall was installed and trapped all of the moisture in the stud cavity.

I used cellulose in my garage attic and I am very impressed with how easy it was to blow in and at how well it works.

 

[Diesel-ME]

Here's a random cellulose question- when they spray the cellulose onto the wall between studs (before you put up the drywall) what makes it stick there (and not just fall out)?

Is it wet (with water) or is it some special non drying chemical or glue that makes it stick together? I would think that if it was wet (with water) the dampness of it would cause the studs to mold and rot when the drywall was installed and trapped all of the moisture in the stud cavity.

I used cellulose in my garage attic and I am very impressed with how easy it was to blow in and at how well it works.

Wet spray cellulose uses water and an adhesive to help stick to the framing members. Some of the builder mags (as I recall the Journal of Light Construction) have reviewed this stuff recently. I'm not sold on it personally. For one thing it would really hold up the building process waiting for ALL the moisture to evaporate prior to vapor barrier and sheetrock. However, despite my skepticism, the wet-blow proponents say it is an efficient and safe product. I does pack really tight - have to give them that.

Of course, unlike loose cellulose, the homeowner can not run down to Lowes/HD and borrow a blower and self-install the wet stuff.

There is another way to use cellulose on sidewalls in new construction. You can install fiber-reinforced plastic sheeting on the empty stud bays and then blow the product in.

Check out this link to an interesting related article.

~paul

 

[Alan L.]

I put low-density foam in every wall or ceiling adjacent to the outside (including cathedral ceilings). I chose not to do the entire envelope and went with blown fiberglass in the horizontal ceilings - R50. Everything was sealed up tight, the attic has a radiant barrier and good ventilation with ridge vents.

First month electric bill showed we used 1700KW in the month of June compared to > 3000 last year. Last year we were in 880 square feet, this year 2200. Prior year had the power to run the water pump and hot water heater, then new house has a propane tankless water heater and the well pump remains on the old building meter. Also, my units are Trane 16 SEER 2-stage whereas the building has a 7 year old 10 SEER unit.

I think its going to be great. I have a section of roof inside an insulated storage area within the attic. When its hot outside the foam surface on the underside of the roof is cool as a cucumber.

All of the insulation together was $8500 which was about 3 times what conventional fiberglass would have been.

The value of the foam is its true R-factor in all conditions, and the sealing characteristics.

I'm sold on foam, although not sold on the entire envelope concept as I couldn't see how cooling an entire huge attic could be a good idea, even considering the ductwork and air handlers would be inside the conditioned space. I could not find a single study that concluded this would save energy vs having good ventilation and ceiling insulation.

 

[crbr]

I installed this in my house about 7 years ago. I am pleased with the ROI.

http://www.icynene.com/InsulationSystem.aspx

 

[heehaw]

i know anyone can say anything: but according to a fairly well know architech here in Arkansas: he has been involved in over 300,000 homes that use cellulose, and there has never been a single documented case of mold or mildew, unless there was a water leak. i am pretty sure, he says there is no need for the vapor barrier or the house wrap if you use cellulose: which saves some $$$: fireproof, rodent proof, roach proof, and keeps wind from blowing thru the electrical outlets, thats the other plus's he says about cellulose.
heehaw

 

[Diesel-ME]

i know anyone can say anything: but according to a fairly well know architech here in Arkansas: he has been involved in over 300,000 homes that use cellulose, and there has never been a single documented case of mold or mildew, unless there was a water leak. i am pretty sure, he says there is no need for the vapor barrier or the house wrap if you use cellulose: which saves some $$$: fireproof, rodent proof, roach proof, and keeps wind from blowing thru the electrical outlets, thats the other plus's he says about cellulose.
heehaw

I don't know about acceptable building practices in Arkansas, but for readers in the north, you ABSOLUTELY and unequivocally need a vapor barrier AND house wrap when using (dry-blown) cellulose.

Heehaw, is your architect friend speaking of wet-blown cellulose? Perhaps there are differences in acceptable use as compared to dry-blown...???...

~paul

 

[heehaw]

all they put in the walls around here is wet-blown: new construction where the walls are open. go to dougrye.com and you can read some of the stuff the architect has written about building houses with low utility bills etc.
heehaw