insulating the attic

[chrisf]

Well I am looking at doing some blown in insulation in my attic. I am looking to bring it up to a r 49 right now my insulation just covers the top of my 2 x 8's ceiling joists. Will I notice the difference in the house immedaitly? I have to put in proper vents before I do the blown in stuff. I am hope to cut my pellet usage down. I burn around 6 tons a season and the the was built in the 1870. I have new windows in the house and brand new storm doors and entry doors too.

 

[Highbeam]

If you already have 7.5" then I doubt you will see a great big huge difference. Going from zero to R49 or even R-30 will be immediately noticable, especially in the floor. Before blowing in more insulation, spend big time sealing all air leaks in the ceiling around things like light fixtures and also holes in the top plates for wires, etc. The air sealing can be more beneficial than the insulation and it is cheap to do.

 

[woodsmaster]

We usuall install it to R-60 or 16" ,but R-49 is pretty good.

 

[Dune]

On a house that old, there could be air leaks all over the place. I would start in the basement, seal cracks in the foundation, insulate the rim joist area or sleepers, whatever is down there, insulate the floor, work your way up, everything High beam said. Electrical outlets in outside walls can be big leaks. Going to r-50 or more in the attic is definitely worth it, but you need to prevent cold air infiltration too.

 

[NH_Wood]

We've had our home for 2 years - inspector told us the attic needed insulation. Had a new roof and siding done a couple months back and my contractor (family friend) said he estimated out attic was at and R-value somewhere in the teens! Sure enough, I looked at the attic and there was simply very little insulation anywhere! Had insulation blown in and brought the R to the low 60's. HUGE difference for me - sometimes I can't believe how long the house will stay at, say, 70* on a relatively mild day (mid-20's or so). Very happy I did it. But, as Jags (edit - HighBeam - sorry!) said, you aren't making as dramatic a change, so you might not see such a noticeable difference. Next year I'm going to insulation the basement floor joists myself - a little at a time. I heard you can lose up to 30% of your heat through the floor - is this accurate?? Cheers!

 

[Dune]

We've had our home for 2 years - inspector told us the attic needed insulation. Had a new roof and siding done a couple months back and my contractor (family friend) said he estimated out attic was at and R-value somewhere in the teens! Sure enough, I looked at the attic and there was simply very little insulation anywhere! Had insulation blown in and brought the R to the low 60's. HUGE difference for me - sometimes I can't believe how long the house will stay at, say, 70* on a relatively mild day (mid-20's or so). Very happy I did it. But, as Jags (edit - HighBeam - sorry!) said, you aren't making as dramatic a change, so you might not see such a noticeable difference. Next year I'm going to insulation the basement floor joists myself - a little at a time. I heard you can lose up to 30% of your heat through the floor - is this accurate?? Cheers!

I have heard 15% heat loss through floor, but I am sure it is different for diffewrent houses.

 

[dave11]

It's a misconception that heat rises. Heat moves in ALL directions equally, proportional to the temperature difference. If you already have say R20 in the ceiling, and you have R0 in the walls, you'd be much, much better blowing insulation into the walls.

Insulation has "diminishing returns." The more you add, the less gain you are making in slowing down the heat transfer. The difference between R30 and R40 is very small. The difference between R40 and R50 is even smaller.

You should get the walls and floor up to at least R10, before adding to the ceiling.

AND seal all the air leaks, as described in other posts.

 

[Dune]

Just for clarity, heat does not rise. True, however, hot air does rise.

 

[homebrewz]

Yep, its winter.. lots of insulation threads, and all are interesting. Rather than starting a new thread, please allow me to ask a couple of specific questions in this one.

So, I'm in the process of sealing up the space in between the boards on the 1st floor/basement ceiling from the basement side with silicone. The stove is on the first floor. Basement is about 45-50 in the winter. Should I be insulating the basement ceiling too? (140 year old farm house). I was under the impression it wouldn't help much. What should I use on the old 8"x8" wood sill beam, foam board, loose bats? I'm worried about the block in air flow might encourage rot in the warmer months.

 

[smokinj]

If you already have 7.5" then I doubt you will see a great big huge difference. Going from zero to R49 or even R-30 will be immediately noticable, especially in the floor. Before blowing in more insulation, spend big time sealing all air leaks in the ceiling around things like light fixtures and also holes in the top plates for wires, etc. The air sealing can be more beneficial than the insulation and it is cheap to do.

Are you talking about just using calk on the inside of the light fixtures?

 

[Highbeam]

If you already have 7.5" then I doubt you will see a great big huge difference. Going from zero to R49 or even R-30 will be immediately noticable, especially in the floor. Before blowing in more insulation, spend big time sealing all air leaks in the ceiling around things like light fixtures and also holes in the top plates for wires, etc. The air sealing can be more beneficial than the insulation and it is cheap to do.

Are you talking about just using calk on the inside of the light fixtures?

I don't use any caulk on fixtures. Instead, I find the box from above and caulk every hole shut on the box, where the wire enters, and also run a bead around the sheetrock/box interface. It sounds tedious but you can do this really fast since it doesn't need to be pretty. From the living space you do no caulking. If there is no attic access then you could drop the fixture and do all caulkling from below but that would be more difficult.

Sheetrockers can get very sloppy when cutting the holes out to fit the boxes.

Hot air rises. Further, the temperature in a room rises as you near the ceiling so the temp differential there is greater so the ceiling most important to insulate. The floor temps are pretty low and the differential compared to 50 degree earth is lower so the floor is less important.

The floors feel much warmer on your bare feet when they are insulated. Major comfort improvement to insulate the floor.

Homebrewz, I have 2" tongue and groove floor 2-4' above a dirt floored crawlspace. I sealed all apparent gaps and penetrations in the T&G with caulk and foam and then the batt insulation was attached with the vapor barrier against the wood floor. The beams supporting the T&G are at 5' spacing but the installers were very skilled with string. I would either insulate the basement ceiling or insulate/finish the basement walls and floor to make the basement part of the living space.

 

[chrisf]

Well I have the isulation for the basement floor so maybe I will try that first. maybe the attic in the spring. If it ever snows I'll take the extra moneyfrom plowing and put it in the attic thanks. Also can you guys give me any info as to pros and cons on doing something with the basement walls, or somthing to use? It is about 6' high just to help stop the cold coming though since there is about 2.5' above grade?

 

[Highbeam]

Are basement walls bare poured concrete? Is it a living space? Is it ventilated. Insulating exterior below grade walls is complicated, lots of choices.

 

[coolidge]

Sprayfoam the walls to a foot below grade, gets in all the cracks and crevices. Bet ive done 300 this year.