Insulating an existing house

"solargary - No insulation in the floors or ceiling, either. Well, behinds the walls of the second-floor room (between the room and the storage spaces) there is eveidence of what might have been insulation of some sort decades ago, but it's hanging in cob-webby shreds, and it disintegrates when it's touched. Would I want to insulate the underside of the roof there in the storage space? (insulating the storage space itself from the outside) Or the floor and wall of the storage area (thereby leaving the storage space uninsulated). Or both? It's hard to describe without drawing a picture and pointing."

p.s. I just read your post again and notice you have snow on your front porch but not on your roof. That is a sign of poor insulation also and you say you have none. Is it the same on the back of the house? Is your roof bare within a day or too while others still have snow? Do you get icicles? Did the shingles last a full 20 years or did they bake or freeze off? Were they much worse on the South side with the sun or around the eaves with melting snow and freezing ice?

You can fix this from the inside. It can take some work but the materials are not expensive. As I understand it you have a triangular storage space behind a kneewall, then a sloped ceiling, then a triangular space above a flat ceiling. Yes? What you want is free movement of air from the eaves to the small space above the flat ceiling without any air entering or leaving heated space. You can then have a vent on either end of the small attic space. The insulation in your climate should be R20 and lay against ceilings and not against the roof sheathing. You don't have room under the sloped ceiling but you can make room.

What you would do is remove all the drywall. It might even be lathing. The rafters are probably only 2x6 in such a house. You need to leave room for air to travel under the sheathing and that leaves little room for insulation. You could strap some 2x4's to them to make them effectively 2x10s though you would lose some ceiling space. It is the sloped ceiling that makes things cramped as when you lower it it makes the room narrower. If these are kids rooms or you are all on the short side it is not so bad. You can raise the height of the flat ceiling to increase volume, but you need to leave enough of an attic to allow roof ventilation our to the gable vents, which you can raise. You can also move the storage space to the inside of the walls rather than the outside. You may need to have some trusses exposed on the inside of the rooms but this can be very appealing.

You don't need to go overboard on insulation but you want to make it worth all the trouble. You don't need 2x4 on every 2x6, unless for structural reasons. One approach simply make room for fibreglass batts and then add vapour barrier and drywall. Another approach would be to sheath with rigid foam and then drywall though this is usually more expensive. You can also get a nice look with a painted wood ceiling but beware of fire reglations. Whatever system you use you will get about R4 per inch. R40 might be difficult but you should get at least R20. You probably want it to be cooler in summer also than it is now.

Without seeing it, I would try for 3.5" of fibreglass batt between the existing rafters leaving 2", and then 2" of foam in 4'x8' sheets against the rafters. This will also provide a vapour barrier. Finally gyproc againt the foam. You can probably screw right through the foam to the rafters. That will give you about R22 I think. About R12 for the fibreglass and another R10 for the foam. You should be able to do this just be removing the drywall or lathing you have now without changing or adding any lumber, not that it won't be messy.

With 6000F degree-days, going from R5, if that's what you have, to R20 will save you (6000 x 24 / 5) - (6000 x 24 / 20) = 21,600 BTU per square foot per year. If heat cost $0.10 per kwh, you would save $0.63 per square foot per year. If you go from R10 to R20, you would only save $0.21/sqft. You really want to be sure you have no more than R10 to begin with. If you really have no insulation then you might effectively have as little as R3. For 1000 square feet of roof that would mean you are losing $1400 out the roof. I doubt this is the case unless you heating bill is over $3000. It is important to know whether you will save $1000 or $5000 over six years if the cost of the project is $3000. Is it hot up there in the summer?

I just notice you have snow on your front porch but not on your roof. That is a sign of poor insulation also. Is it the same on the back of the house?

The pitch on the main part of the roof is much more so than the porch roof. Also, when I took this picture, the snow was in the process of melting pretty fast - and the house faces south.

Is your roof bare within a day or too while others still have snow?

I'll have to take notice this year; not sure.

Do you get icicles?

no

Did the shingles last a full 20 years or did they bake or freeze off?

They were old. Also, the attic space (behind the knee walls upstair) was totally unventilated. The roof was baking. When we had it torn off and replaced (there were two layers of shingles), we have a solar attic fan installed. I'm sure that will save the baking of the new roof.

Thanks for the advice on the storage space - I didn't quite know whether to insulated under the roof, or insulate the floor and behind the knee walls.

The part of the storage space that is directly above that room on the left, where the roof is pitched - my daughter thinks make a great "Club House". And she's right. I may just give her a space heater in there just for when she's using it - which right now, is only when it's not hot - OR cold, outside.

By the way - the bedrooms are both downstairs.

Also - the garage-turned-living space at the back of the house (in the 60's or 70's - linoeum flooring on concrete, and wood panelling on the walls - also concrete block) - is DH's domain. He's been wanting to strawbale around the outside of it. The north side has a covered patio, but the rest would have no roofing over it. I'm assuming it won't be very insulating once it gets wet, and would have to be re-done every year. hardly cost effective. So he said, ok, we cover the top & outsides with plastic!!

He's very enthusiastic, but I don't think he always wants to think things through. Should I let him to the north side which is covered?

And what can I say sepcifically about doing the other walls - when extending the roof is NOT going to be an option anytime soon?

Here's a recent picture - while the roof was being done - you can see the solar attic fan.



You can *almost* see the garage-turned-living-space in the back...

Aha. So there are no rooms upstairs just some storage space and a fun place for kids to hang out? In that case you really want to insulate the floor, but you still want to be able to walk around. Different problem. I see the solar attic fan. Not exactly sure why it is there. Is it blowing fresh air in or out? I also see the ridge venting. Nice job.

If I wanted to insulate downstairs from above but still be able to use upstairs for storage and play, it gets a little more complicated because is is probably quite cramped and there is not as much money to be saved by insulating a living space. There is probably a lot of wiring and stuff also and a lot of lumber and strapping running this way and that. That makes things more difficult also. The ceiling might be any easier to access than the floor, and then the storage and play area will be a little nicer also. Trouble is you really don't wan't to bake off those shingles in the summer so the more open the better.

Not sure whats going on in the backyard. I would go for a hockey rink myself.

There IS a room upstairs - one long one. It's playspace, guset bedroom, movie veiwing area, and sewing corner all in one.


The attic fan vents the baking air out of the storage space along the south side of that room. It''s considerably less oven-y in there in the summer now.

No help to you but I had friends in the Washington DC area who lived in a drafty wood siding house. They removed the siding one wall at a time, removed the old rockwool insulation, added additional wiring for outlets, put in new fiberglass insulation, covered the wall with wrap and then put the boards back on in reverse order they came off. They did it all as a do-it-yourself job, with Irene doing most of the work by herself.

Hi again,
I'd have a look at the storage room floor and see if you can blow cellulose in the space between the lower floors ceiling and storage room floor.
It may be necessary to drill some holes in the storage room floor to get the blower nozzle into the space. Cellulose is pretty good at filling irregular cavities. You may not be able to get a lot of thickness this way, but as JAK points out, some insulation is much much better than none.

Before you blow the cellulose in, get some cans of the polyurethane foam (Great Stuff is one brand), and seal all the places where wires or pipes come into the attic space from below (where you can get to them). Its much easier to do this before there is insulation in place.

Also, if you have heating ducts that go through the attic, then seal all the joints with duct mastic (not duct tape) -- this can be a big heat saving. The duct mastic comes in a can -- its about the consistency of wet plaster, and you just spread it on with your hands -- very easy, and permanent. If the ducts are not insulated, then insulate which ever ones you can get to -- they make an insulation wrap for this purpose.

You might like the book: Insulate and Weatherize by Bruce Harley -- I used it as my bible when I worked reducing the heat loss from my house -- it covers just about everything, and is right up to date -- about $19 from Amazon.com.


Gary
www.BuildItSolar.com

Before I moved into an old (1850's), drafty, brick house a few years ago, I had the carpenter build a frame of 2 x 4's FLAT (not on end) on the floor inside each room to the dimensions of each outside wall (one at a time). When he raised and fastened each new "wall" of flat 2 x 4's to the existing old plaster wall, I put batt insulation in between each section, and then he put drywall over all of that. It took a few inches off each room, but the house feels very well insulated now. I also tore up all the flooring in the attic and put insulation down and replaced the floor. Well worth it, because I still have the old oil burner - can't afford a new corn-burning furnace yet....

Even is the roof is just 2x6, you could leave 2" for ventilation up to the ridge vent and add R11 of fibreglass batt at a cost of $0.75 to $1/sqft. If you double 1000 sqft from R10 to R20 for $750-$1000 you will save 7,200,000 BTU in 6000F degree-days, and be much cooler in summer. It would pay back roughly $150 to $200 per year, so about 5 years. You need to leave at least 2" of insulation though or you will bake off your shingles.

A greenhouse or solar hot water heater up there would be interesting.