ceiling insulation question
Ok....i bought this 80 year old house a couple of years ago. my heating bill ranges from $600 to $900. I realized that I had no exterior insulation in the house.
I contacted a company that specializes in energy conservation services. they did a airflow test...it wasnt good... too many leaks...too much of flow..
they will be doing exterior wall insulation, fix the leaks in basement and recommended increasing cellulose insulation of the ceiling to 8 1/2' from current 4". I didnt like that idea since my attick is spacious and i plan to covert it into a room. the floor is pretty much open right now since i had house rewired and electrician removed all the board.
What are my options here. I would like to go with 8 1/2 "cellulose. but rafters are 4 x 2. what is the best way to increase the height of the floor. Should i go with fiberglass insulation instead since it has better r value . it looks like I need an R value of 38 ( from another post on tis forum).
thanks in anticipation.
Hi Christy - I'm working on insulating my attic also. Some of the things I learned make me wonder about your plans.
From all that I've read, cellulose blown-in insulation has a higher R-value per inch than fiberglas. The fiberglas insulation companies won't tell you that, but I'm sure I read that on the Dept. of Energy website. Maybe one of the contractors on this site will know.
You say you want to build a room in your attic. Make sure you talk to an arcitect or a structural engineer. If your attic wasn't intended to be used as a room, you're asking for a lot of trouble putting one up there. Call your local building inspector and ask a few questions. What he'll probably tell you is that you can't build a room in your attic, you have to put on an addition. Don't try to avoid getting permits for this, it's a huge undertaking and you'll want to make sure it is all legal and most importantly, safe. If I understand you right, the 'floor' of your attic is made of 2"x4"s? That is fine if the space is meant to be used as an attic, but if you are going to have people walking up there and furniture, etc. 2x4's aren't meant to hold that kind of weight load. I'm pretty sure you need at least 2x8's for the floor joists. Honestly, I'm certainly no expert about this, but be sure to ask the right people a lot of questions. It would suck to go to all the trouble and expense only to have the ceiling cave in on you below.
I know of a couple who had their attic turned into a bedroom. They asked a builder about putting one up there and he said, "Yeah, no problem" and told them that getting permits wasn't necessary and it would only add to the time and expense of the project. He was lying, so they shouldn't have believed him, but they didn't know any different.
If you get snow where you live, do you notice an ice build-up on your roof? If so, it's because warm air is going into your attic from rooms below and heating that 'cold zone' enough to melt the bottom layers of snow and it re-freezes when it gets to the lower sections of the roof, causing ice dams and huge icicles. That's how I found out that I needed to take a look around up there.
Before you have insulation added, make sure you seal any gaps that allow warm air to flow up into your attic. In an 80-year-old house, there are probably some gaps. I had a lot more gaps than I would have expected, and my house was built in the early 70's. I have most of them sealed and I've added baffles for the cold air to come in and I can already feel a big difference in the temp. of each room, especially down by the floor and I haven't added any insulation up there yet. It's still just the original R-19. I had a hard time believing that my floors were cold because of my attic. It didn't make sense to me. But I was told that you lose 40% of your heat through the roof.
Table 1. Locations of Attic Air Leaks and Sealing Methods
You said that the electrician took the floor boards out of your attic. That's probably a good thing, because if you put boards down over the blown-in insulation, they compress the insulation and lower the R-value because insulation isn't as effective when it's compressed.
I'm anxious to see if all of my work and expense will help next summer. We had to have a new furnace and A/C put in 3 summers ago. And even with it being new, our basement has always been freezing with the A/C on while the upstairs was way too warm. I think it's from the sun heating the attic and warm air was coming down into the house through all those gaps and thin insulation.
Hopefully all this work will be worth it for you, and I hope you can bring your heating bills down. Sorry if I've told you things you already knew, but most of what I've learned is from other people telling me what I needed to check for and do and it's helped a lot. Good luck.
Hi again. If you go on www.glennhaege.com and up toward the top of the page, click on 'columns'. You'll get a long list of his articles that will be helpful. This guy does a syndicated radio show about home improvement on Saturday and/or Sunday mornings on some AM radio stations.
So that you don't have to search through every article, here are the dates of the ones I printed-off about the subject of insulation:
10/08/2005 - 'Take preventive measures and stop ice dams before winter'
11/18/2006 - 'Department of Energy says R-49 insulation is best'
11/24/2007 - 'To ease higher energy costs, insulate, insulate'
There are probably some other articles about insulating in there.
Oh, by the way, the chart in the previous post is from the website:
www.buildingscience.com which is a great source of information about insulating. I think someone here at diychatroom gave it to me, or I got it from another chatroom.
Since your floor boards are out of your attic, this is a great time to utilize polyurethane foam insulation.
The cost is higher, but at R 7 per inch, you will soon realize that you will quickly earn your money back in energy savings, and once the initial installation is paid off, your foam insulation is putting money back into your pocket.
Now, however, is the time to decide if you can/are putting a room up there. Like the previous poster said.... get in contact with the building department, or better yet an architect. Many times, a new room up there might be as simple as sistering floor joists next to the existing framing members to increase the strength of the flooring system. If you do this, you may want to consider installing blocks and lathe to the existing framing under your roof decking in order to create an airflow under the roof deck as well as a surface to spray the insulation to. I dont like going directly to the roof deck with the foam insulation. This procedure, of course, is great for insulating the new room as well.
Closed cell foam insulation creates a complete air barrier if properly installed and has double the R value of cellulose and fiberglass. If youre going to be in the house long enough, the re-fit will pay for itself.
If you would like more information, email me and I can run some approximate energy saving calculations for you.
Just out of curiosity, is it possible to spray that foam in-between the 2x4's of walls that are already covered with drywall or wood lath and plaster? I know blown-in insulation can be done in walls that are already finished, but would it possible to spray the interior of the wall cavity's of a house with the foam and be confident that every square inch is properly coated as it would have been if the drywall/wood lath had not been put up yet?
I can't remember the term used (bridging?) when cold air is transferred in the winter from the outside of the house, through the 2x4 studs in the walls, through the drywall and into the room, but does the spayed foam do anything to prevent that transfer of cold from the exterior of the home to the interior of a room from happening?
I'm honestly not trying to give you a hard time by asking so many questions. But I've seen that stuff being used on the Holmes on Homes show and always wondered how it works and how long it takes for it to pay for itself. It seems like it is the insulation that makes the most sense, but is also the most expensive. Thanks. Have a good day.
that is lot of good information.
Polyurethane foam sounds like a great idea. is it fire safe though?
I will not go for room in attic without consulting a structural engineer. Architects really cant tell you this for sure.
I am actually doing the insulation of exterior walls as well. I hired a professional energy services company. they will also do caulking etc in the basement /attic etc to make the house more airtight. these guys did a airflow test of my house a few weeks ago...the result was around 4500 ( dont recall the unit)..they had estimated an ideal # of around 1200 .
thanks for the help
this foam has some safety issues as well
The only safety issue that I know of is that there has to be something like drywall between the foam and the living space because if there is a fire, the fumes from it would kill you before the flames or smoke would. I'll look at the link you posted. Thanks. Have a good night.
I talked to foam insulation guy today. he recommended spraying the foam under the slope of the roof and along gabrels and not in the attic floor. he said he could spray foam in the floor though)
he said using open cell foam(R value/inch) would be lot cheaper than closed cell foam( Rvalue 7/inch) in achieving R-value of 20.
Does this guy make sense. i know the local code requires R value of 38. Can anyone share the experience with foam insulation.
Open cell foam will yield you aged r factor of 3 per inch. It will also allow moisture to pass through it. As we all know, water conducts rather than insulates. I have been tweaking specs for foam insulation.
Numbers don't lie, and when trying to achieve high R values, an air seal, and a vapor barrier, closed cell is the way to go. Open cell foam will be "cheaper" if youre looking to fill the cavity instead of achieve higher r value.
I dont like foaming to the underside of the roof deck. Sure, the moist vapor and attic heat issues are eliminated, but it also creates a heat sink. When the sunshines on your unvented insulated roof deck, the sunshine cannot radiate through the insulation, which means it will keep your roof deck and shingles much hotter than it would be with a vented roof deck. This can bake both your shingles and your decking, leading to premature failure and expensive repairs. Insulators dont seem to see things this way.
Elk had a spec for it before GAF bought them out, but I think they knew about this condition and the warranties were severely shortened.
You make a good point there about the shingles getting baked or frozen. Never thought about that.
So I guess you are recommending closed cell foam in between rafter of the attic floor and keeping the attic ventilated?
What insulation do you recommend for a small flat room. 12x25. I have posted issues related to that roof separately. I am planning to redo the roof but I am not sure what to do as far as insulation is concerned. This roof has minor leak which had damaged a tile . So i ripped it off and looked up through the ceiling. it looks I have a water proof sheet which has about 1" insulation between 2 layers. Is this enough? roof board seems to be in great condition and i didnt notice any water damage.
There is about a foot high empty space above the insulation. Can I have cellulose blown in into this empty space. The insulation guy refused though.
I know I will have freedom to do whatever I like if I decide to complete rip the current tar and gravel roof off. What is best insulation that is recommended for such a small flat roof.
today i went up into the attic to make sure everything is ok . energy company guys are coming on wednesday. they are going to airseal the attic /basement and do the insulation on exterior walls of the house. i had told them i wasnt sure about attic insulation yet.
I contacted a few foam insulation companies. they seemed to be pushing open cell foam more than the closed cell foam. one guy told me that they dont put more than 3" of closed cell foam. other guy had no clue anout open cell/closed cell types. he was going bu pounds. So i am confused!
Interesting thing happened today. When I was in the attic , i looked at the rafters..they looked bigger than 2x4s... i measured them ..they were infact 2x6s... i looked the the space ...it i between 6-7" deep. The guy had mentioned increasing cellulose insulation "from current 4" to 8 1/2"" so i assumed i had 2x4s.
With blown in cellulose i will get an R21-22.Would it be cost effective to put 6" of closed cell foam (R40) at a cost of $5000. That is the quote i got.
Hi Christy, here is a website for you to look at. www.walltite.com
After clicking on 'United States', up in the right corner there is a frequently asked questions. It looks like there is a lot of information you could use. If possible, hold off on having anything done until you have all the information you need to make the right decision, especially when it involves thousands of dollars.
There is a show out of Canada called 'Holmes on Homes'. The host/contractor is very fussy about the products he uses and he uses a company in the Toronto area that uses this Walltite product. They come in and spray and when they are done "you can heat a room with a match". That stuff seals it up very well. If I remember right, they use closed-cell because it doesn't let water penetrate through it and it acts as a vapor barrier. Their website should tell you what you need to know. Good luck sorting it all out. It's hard to know who to believe when you have several companies all telling you something different.
Walllite seems like a good product. I will look into their roofing system for my flat roof.
I decided to go with the current contractor and they started the job today. They started with air ceiling the attic with some kind of foam . I let them place about 15" of cellulose along the periphery of the house and 6 " in the middle. I already noticed a major change in temperature in the house. They started the exterior wall which they will finish tomorrow.
in the attic they left the recessed lights without the board on them. I realized the cans were not IC rated....I have no clue why i didnt get the IC rated ones... they did surround the cans with aluminum . do i really need to leave them open to the attick? i did not read anything like that in the installation instructions
If I'm understanding you right, those recessed lights can't be covered up tightly because they have to have open space around them so they don't overheat. The directions to the recessed lights we had installed in our basement said to leave at least 3" of space between the light and the insulation.
When they blew the insulation in, did they bring the hose through the house or down through a vent in the roof? I'm just wondering because so far we've talked to two different companies about doing the blown-in insulation in our attic. One said they come in through a window and the other said they come in through the roof.
I'm glad your house is warmer now. It will be interesting for you to compare your old utility bills to the new ones. Hopefully the $600-$900 heat bills will drop drastically.
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