Insulating an existing ceiling


Old 11-16-05, 10:54 AM
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Question Insulating an existing ceiling

I am trying to help my parents out. They have a house that was built in 1971 or 1972. They recently had an addition put on the house. During the construction, the contractor noted to them that their exterior walls hardly had any insulation, and what was there was in poor shape. Last year, they were hitting about $500-$600 a month for their heating bills, and that is only keeping the house at around 65-66 degrees. My Dad is retired and home all day, takes blood pressure medication, and always feels cold. After hearing about the wall insulation, I thought about their ceilings. The living room has a large cathedral ceiling (no attic access above). I think the ceiling (remembering from what I could see in other parts of the house) is probably shingle, plywood, roof members, and then drywall on the bottom. No insulation. I think they lose a lot of heat through their roof. Unfortunately, they had a new roof put on about 8 years ago and the roof was not insulated at the time, just a ridge vent installed and new shingles. Is there any easy, inexpensive way for them to insulate the roof? I am going to help them re-insulate the attic, which covers the bedrooms on the first floor. But the other half of the house (partial second story and cathedral ceiling) don't have access above the drywall ceiling. Is it possible to insulate without having to tear the roof off? With gas prices having increased, they could be paying $700 to $800 a month this year to heat their house to only 66 degrees. I am also going to try and help them insulate the exterior wall cavities with Handi-foam, although it is a little expensive but will hopefully pay itself off in a couple of years. Any thoughts are appreciated to help my parents out. I have even thought of trying to get them to install a pellet stove to heat the living room since it might be cheaper than running the furnace all of the time and would be in the room with the cathedral ceiling, but they run about $1800 and up.
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Old 11-16-05, 07:27 PM
Join Date: Mar 2005
Location: USA
Posts: 6,128
Insulating an existing ceiling

I have a similar situation, but my time table may be different. Your situation and house layout may be different than mine, but perhaps some of the appraoch coul work for you. I have about 8000 degree-days of heating and a north and east exposure, with some heavy AC periods in the summer. The cathedral ceiling is a killer - comfort and utilitywise.

I have a townhouse with an open living room/dining area/kitchen that occupies about 60% of my upper level. It has a vaulted ceiling (12') with scissor trusses and no room for extra insulation. I just moved in and plan to put up 2" of rigid styrofoam on the ceiling, add a couple of needed lights/fans, and sheetrock the ceiling. All one open area, so it is a pretty easy job.

When the contractor looked at the job, he suggested also doing the walls (only 2x4s with R13) at the same time. It would involve the north and east walls (70 linear feet). There are only two openings - an oversize sliding door (7') and a large (5') sliding window. The other wall has no openings except the split level entry down about 4'. I would have to retrim those and add extensions to the electrical boxes. I have not decided on that part of the job, but for the extra amount, it is very tempting to the point of cost and common sense.

I don't know if this gives you any options for your house, but I understand your thoughts on knocking down the utility bills and making it more comfortable.

Good luck on your project.

Old 11-17-05, 08:25 AM
Join Date: Jul 2005
Location: Ottawa, Canada
Posts: 857
Here is some information on how best to insulate a vaulted ceiling...I hope it helps with your situation:

Another helpful link on attic insualtion:
Old 11-27-05, 09:19 AM
Konrad Fischer
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Thumbs up Some additional remarks

may be helpful:

What we found out by testing (Lichtenfelser Experiment) in Germany and by comparing additional insulated appartement houses with the same houses in direct neighbourhood without any improvement ref. insulation:

There is no insulating effect compared with solid materials like wood and brick.

We had only 10 min IR radiation from a redlight bulb on different insulation materials each 4 cm (in opposite ranking: Fiberglass, Styrofoam, Foamglass, Brick, Wood fiber board, gypsum card board, solid pinewood). The temperatures are measured on the back of the boards, fiberglass had 40 degrees increasing, solid wood none!

Besides the lightweight insulation has no capillar activity, what means this materials will never dry out the condensate what must go in, in spite of all vaporproofs, which will be moistured and moldy after some years as our experience shows. I do measure this with my equipement so often in my building consultations all around Germany.

So I recommend not to crumble some lightweight insulation in your construction, instead take solid wood boards if you must have a additional thermal insulation f.e. in attics. About 6-8 cm would be good. If you have a masonry or solid wood wall, no additional insulation is necessary at all. In summer cool, in winter warm, thats the effect of solid material enveloping the rooms.

Some explanations ref. radiation and heat conductivity:

The problem is the way to measure the R-value. Not many in building branche
knows how this is done. Warm air is ventilated to the proof material, cools off and is warmed again outside the 'proof box'. The amount of energy to rewarm is the base for the R-value. It tells only something about cooling of warm molecules on colder surface molecules of the test material.

But: Does the cooling of your hand on a steel plate and a carpet in your room with both room temperature say anything about the wandering of IR radiation through the materials?

Will sunlight - also an electromagnetical radiation - shine through an 1 cm board of styrofoam? And wood? So you can see what works best against IR
radiation. And it is IR radiation, what is reasonable for about 99% of temperature losses through material, believe it or not.

And what is going on in a heated room? In a 20 sqm room there are about 60 kgs heated air giving energy in the facade wall, but about 5-10 tons of IR-radiating wall surfaces, the radiation is nearly on the level of air temperature, you can measure it at the wall by IR-thermometer. So about 99% of the heat transport through materials is radiation (by photones/phonones).

So lightweighters in the building construction are a really pest and only a fake and hoax of 'our' industries and their obscene slaves in science and administration! They damage buildings, invests and - most important - make persons ill with asthma, allergy etc. Even in cellulose insulation is found mold after some time, in spite of all the poison (borates) they give in against it.

Thats the thing: No lightweighters as thermal insulation in and on the walls, in attics, under floors, in the foundations and so on. There is only one good purpose for those - as carpets, to keep the feet warm. Because the molecular contacts are fewer than the marbles on the floor can offer to the warm feet. And so there will be fewer thermal losses by direct molecular contacts. Inspite they have the same room temperature. You can prove that also by measuring with an simple IR thermometer.

Surprising? But true. And well known in earlier centuries from all building experts.

Look on the good old buildings. Modern craftsmanship and engineering is the biggest danger for them, isn't it?

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