Old home, poor insulation

jwal10 · #21 11/11/10, 08:04 PM

Quote:

Originally Posted by Patt

We had the same air conditioner issues and our roof was also asphalt shingles over plywood. Our contractor who is very green told us we needed to go to a white metal roof with foam insulation underneath because we did not want to put in a ceiling. Since our cottage is so small having it open to the rafters makes it seem bigger and we didn't want to loose that feeling of space. So we went with a very pale grey metal roof and 5 1/2 inches of foam underneath.

This is the right way, the roof sounds too flat for 3 tab shingles anyway. Use an engineered barrier over the existing roof system so no tear down, foam insulation layer, then roofing. The other way is to use a membrane system over the foam insulation. Install a ridge vent at this time....James

artificer · #22 11/11/10, 09:04 PM

Quote:

Originally Posted by Nevada

I find the local A/C contractors' strategy of using an A/C system twice as big as it would need to be if the home were properly insulated to be a disappointment, to say the least. From what I understand, the 4 ton A/C systems are the norm in this subdivision, just to cool 1000 sq ft homes. Sheesh!

I don't understand this statement. Did you ask him for A/C, or did you ask him to insulate and install an A/C system. It sounds like he was right on the money in what he suggest for what your house needed. Insulating is the first step, but if you didn't tell him that, he went with the condition of the house as it was.

If you were going to tear off one panel at a time, I would just go ahead and do a total tear-off. This would allow you to scab on wood to the top of the rafters to allow more insulation and include venting area. You need a ridge vent for each bay that the rafters create.

Michael

The Paw · #23 11/11/10, 09:05 PM

Quote:

Originally Posted by Nevada

I haven't see one. It seems to all be sealed up, except on the ends of the house (in the blocking wood). There is a 1" hole with screen at the center of each piece of blocking.

If you decide against blowing in cellulose and want to go with rigid styrofoam on the exterior, you can put it on 1 x 3 strapping and allow a little air space between the styrofoam and your existing shingles. cover it with metal roofing and include a ridge cap. The metal roof will reflect a lot of heat and the air space underneath will keep the shingle surface from heating up.

Tearing out all your ceilings and spraying foam would work best, but I am guessing that you don't want to do that. If I did go to all that trouble, I would certainly put in those ridged sheets that keep the foam an inch off the underside of the roof and see if I could retrofit a ridge vent. Of course, if you have the whole ceiling torn down, you could create a mini attic space and vent it with gable vents or louvered roof vents.

Nevada · #24 11/11/10, 09:16 PM

Quote:

Originally Posted by artificer

I don't understand this statement. Did you ask him for A/C, or did you ask him to insulate and install an A/C system. It sounds like he was right on the money in what he suggest for what your house needed. Insulating is the first step, but if you didn't tell him that, he went with the condition of the house as it was.

If these boneheads want to purport themselves as A/C experts, they need to consider the clients' best interests. The proper answer was to advise the client that houses in that subdivision are not fit for A/C as they were built. Instead he simply recommended a 4 ton system.

I'm not going to accept that he knew that it would take 4 tons to cool a 1000 sq ft home without knowing there was more to the story. He knew, and he held the information back for personal gain. After all, he'll make more on a 4 ton system than a 2 1/2 ton system.

fishhead · #25 11/12/10, 07:43 AM

I wonder if it's possible to detach the entire roof and raise it to gain enough room for insulation and air space. The material cost wouldn't be that much, just some 2x8's or 10's placed on edge.

I guess it would depend on how the ceiling and roof is already attached.

wy_white_wolf · #26 11/12/10, 09:32 AM

Quote:

Originally Posted by Nevada

....I don't have the greatest roof in the world. It's just rolled roofing on top of plywood. I would like to replace it with 30# builders felt & traditional asphalt shingles anyway. My plan is to tear-up the rolled roofing, then remove one plywood panel at a time, inserting two layers of R-13 fiberglass insulation into the 2x8 void space. After doing that to the entire roof I'll add 30# felt and top with asphalt shingles. That should hold me for 25 years or so.....

I would consider forgetting about fiberglass insulation and look into using a spray foam insulation. You could easily spay in 3 to 4 inches from above and leave the rest open for air circulation. One could even spray just one inch to create a vapor barrier and add only 1 layer of fiberglass. That would still leave @2.5 inches open for air circulation.

Adding a ridge vent would help increase air circulation and help keep the roof temp down.

Spray foam would also have the added benifit of being a vapor barrier. While in '54 a vapor barrier wasn't needed, it is now as you've pointed out the rise in humidity of the area.

Another option would be to not remove the plywood and install rigid insulations panels over them. While I've seen others do it, the possiblity of condensation in the plywood does bother me. It's one or those things you may never no about until lots of damage is done.

WWW

crobar · #27 11/12/10, 11:29 AM

Here in southern Illinois we have fellow on the radio named Doug Rye calls himself doctor of energy. His whole call in program is about energy saving. A few years ago I called in asking about my ceiling insulation in my older doublewide. He recommended I blow the ceiling cavity full of cellulose, not to worry about air space. I drilled holes every 4ft between ceiling trusses and between all the trusses, pumped it full. It's been 10yrs has worked wonderful.

Nevada · #28 11/12/10, 12:24 PM

Quote:

Originally Posted by tinknal

No, I mean how about installing one. Does the roof have a peak or is it one single slope?

The roof has a peak.

ronbre · #29 11/12/10, 12:52 PM

there are free government insulating and weatherstripping plans out there you might be able to take advantage of and if not, you should be able to claim any things you buy in that area on your taxes for next year

Pelenaka · #30 11/12/10, 01:31 PM

Having lived out in China Lake N.A.S. I often wondered why the locals didn't hang either a shade cloth or install a trellis a foot off of exterior walls. It would create a cooler buffer space. Our front door was recessed with creeping myrtle growing against the foundation. That portion of the ranch home was relatively cool (low eighties) compared to the sunny exterior walls which reached above 110 degrees in August.
Are there alot of tradional adobe style homes built ?

~~ pelenaka ~~

fishhead · #31 11/12/10, 01:33 PM

We hung strings from the roof one year and grew morning glories and scarlet climbing beans. The house stayed 10 degrees cooler than the outside all summer.

I know from experience that it works great at keeping the house cool.

Patt · #32 11/12/10, 06:37 PM

Quote:

Originally Posted by crobar

Here in southern Illinois we have fellow on the radio named Doug Rye calls himself doctor of energy. His whole call in program is about energy saving. A few years ago I called in asking about my ceiling insulation in my older doublewide. He recommended I blow the ceiling cavity full of cellulose, not to worry about air space. I drilled holes every 4ft between ceiling trusses and between all the trusses, pumped it full. It's been 10yrs has worked wonderful.

Cool! He's from Arkansas and I didn't know his program went anywhere outside the state. We listen to him too.

Loquisimo · #33 11/12/10, 07:12 PM

Cinderblock construction was EVERYWHERE in Nevada in 1954. Whole apartment buildings were built of it in Reno. When Silver Springs was founded in 1949, the first settlers hauled in huge truckloads of the stuff to build houses and commercial buildings. Before that, a lot of houses were built of red clay brick in Reno in the 1910s and 1920s, until the cost to ship wood came down enough that it was cheaper than block.

Back then, the concrete block made things cooler inside, or at least that was the justification. Of course, they used evap coolers. Las Vegas has way too much turfgrass and fake lakes for being in the middle of the desert-even today, the only turfgrass you'll find in Silver Springs is at the schools. The desert is not naturally humid, for cripes sake! You wanna save on AC bills, move north. The only problem is that the HIGHS in Reno in December rarely get out of the 30s. I'm thinking that you definitely need to get the roof insulated, and you need to install white composite shingles.

**highlands** · #34 11/12/10, 07:48 PM

We made the mistake of trying to retrofit our old farm house and make it habitable. Waste of time and money. We then built a tiny cottage for about $7K which takes almost nothing to heat. I wish I had done that sooner. I had not bought this land for the old farm house, it just happened to be on the land so there was this 'should' in my mind that it 'should be fixed up and used'. Foolish me.

Nevada · #35 11/12/10, 11:36 PM

Quote:

Originally Posted by Loquisimo

Cinderblock construction was EVERYWHERE in Nevada in 1954. Whole apartment buildings were built of it in Reno. When Silver Springs was founded in 1949, the first settlers hauled in huge truckloads of the stuff to build houses and commercial buildings. Before that, a lot of houses were built of red clay brick in Reno in the 1910s and 1920s, until the cost to ship wood came down enough that it was cheaper than block.

Back then, the concrete block made things cooler inside, or at least that was the justification. Of course, they used evap coolers. Las Vegas has way too much turfgrass and fake lakes for being in the middle of the desert-even today, the only turfgrass you'll find in Silver Springs is at the schools. The desert is not naturally humid, for cripes sake! You wanna save on AC bills, move north. The only problem is that the HIGHS in Reno in December rarely get out of the 30s. I'm thinking that you definitely need to get the roof insulated, and you need to install white composite shingles.

Concrete block is indigenous material for Las Vegas. There is a limestone quarry and cement plant just north of the city along I-15 at Apex summit (that's just north of the speedway). That provided building materials that didn't need to be shipped. By the 1970s the 2x4 lumber transportation thing was well developed enough that it was cost effective to build 2x4 frame homes with stucco exterior. Those homes could be built faster and cheaper, without the need for skilled brick layers.

8 inch concrete exterior walls are great in climates where the outdoor temperature goes both above and below the comfortable indoor temperature every day. Under those conditions the thermal mass keeps the house comfortable.

Quote:

Originally Posted by Loquisimo

I'm thinking that you definitely need to get the roof insulated, and you need to install white composite shingles.

Yes, I suspect that's the plan I'll have to follow.

tinknal · #36 11/13/10, 06:05 AM

When you do the roofing job put a ventilated ridge cap on. It is easy and cheap. If you blow in insulation it should settle a little if you don't pack it too tight. this should give you adequate ventilation.

bloogrssgrl · #37 11/13/10, 06:53 AM

Quote:

Originally Posted by wy_white_wolf

I would consider forgetting about fiberglass insulation and look into using a spray foam insulation. You could easily spay in 3 to 4 inches from above and leave the rest open for air circulation. One could even spray just one inch to create a vapor barrier and add only 1 layer of fiberglass. That would still leave @2.5 inches open for air circulation.

Adding a ridge vent would help increase air circulation and help keep the roof temp down.

Spray foam would also have the added benifit of being a vapor barrier. While in '54 a vapor barrier wasn't needed, it is now as you've pointed out the rise in humidity of the area.

Another option would be to not remove the plywood and install rigid insulations panels over them. While I've seen others do it, the possiblity of condensation in the plywood does bother me. It's one or those things you may never no about until lots of damage is done.

WWW

I would go with either of these options.

The only other option I might add is, if you are dead set on going with an asphalt shingle roof, tear it off and cut foam board to fit between the rafters. You could easily get up to 6 inches of insulation in there and still have a 2 inch air space. At the point where you are putting the decking and shingles back on, you can incoporate the ridge vent.

Don't forget to properly address the soffit as well.

Dead Rabbit · #38 11/13/10, 07:34 AM

true ridge vents are useless if the soffits arent ventilated. or at least some gable vents. but vented soffits are best. incourages the flow of air from low point to high point.