Then let me add this bit of info, our house was built with the ducts poured in the concrete slab, is something like a leak test still worth the effort?
Then let me add this bit of info, our house was built with the ducts poured in the concrete slab, is something like a leak test still worth the effort?
914Driver wrote: Make sure the gable and sophit vents are clear.
Soffit vents are meant to work in conjunction with ridge vents. A common mistake is to use them with gable vents. They negate each other.
Soffit vents are designed to draft from bottom to top- to encourage the natural thermal convection in the attic and draw cooler air in through the soffit. Gable vents are designed to flow from side to side.
If the stack effect which begins at the soffit meets a cross draft before it exits the ridge, it pretty much traps the air in the attic.
The BEST attic systems are completely unvented, but that's a bit complicated and almost impossible in a retrofit.
z31maniac wrote: Then let me add this bit of info, our house was built with the ducts poured in the concrete slab, is something like a leak test still worth the effort?
Still worth the effort, although the fix might be more complex.
A blower door test in conjunction with a duct blaster test can tell you EXACTLY how much air is leaking outside the building envelope. Under the slab is outside the envelope.
If there are leaks, it can draw in humidity, contaminants, and perhaps other bad stuff like radon.
If leaks are found, some can be fixed by reaching down the outlets and sealing them from the inside. If the leakage is bad, you might want to consider replacing several of the runs.
But even if fixing duct leakage is not cost effective, the blower door and infrared camera will ID other leaks that ARE worth fixing.
A perfect house is not possible. The testing will let you properly analyze the building so you can have a greatly improved house.
If there were enough interest, I would consider a road trip to do testing on a circuit of multiple houses.
Do you have several friends that might be interested?
10 houses worth of testing might be worth a trip to OK, or anywhere else.
tuna55 wrote:Josh wrote:Well the incandescent bulb isn't filled with mercury, and doesn't require all of the nasty environmental concerns that go along with manufacturing something that is filled with mercury. It's not that much of a joke.tuna55 wrote:Well, so is a CFL. But in the summer, the CFL isn't using a bunch of energy unnecessarily negating your efforts to cool the house. Even if it's not hurting anything in the winter, in the summer the incandescent wastes energy twice, once in the bulb and then again in your A/C. I concede that it may have been a joke, but this is a foolish argument.darkbuddha wrote: Going to CFL saved another few dollars a month.In the winter an incandescent bulb is 100% efficient.
Cool, but wrong thread. Have a nice day.
SVreX wrote: If there were enough interest, I would consider a road trip to do testing on a circuit of multiple houses. Do you have several friends that might be interested? 10 houses worth of testing might be worth a trip to OK, or anywhere else.
Hmmm, not likely.
My friends are all lazy/apathetic when it comes to stuff like this.
ultraclyde wrote:foxtrapper wrote: But then the black solid rubber roof was installed. With an inch thick layer of foamy underlament stuff.Rubber roof, you say? Details? Linkature?
No linkies.
Old farm house with a Cletus brothers flatish topped dormer as the back half. Steep standing seam metal on the front. Old house, so no ridge venting and no reasonable way to do it. Attic is semi-finished and useable, except for temperature.
Old roof was removed down to the timbers and tree parts (no kidding). Many repairs and adaptations were made, getting things back reasonably plumb and stable.
Plywood over it all, then the foam board thingies. Lots of 4" anchor thingies screwed onto it all to hold the foam boards down onto the roof.
~6mm rubber membrane laid down over it. Single seam, double taped (top and bottom). All glued down onto the foam. Flashing stuff around the edges to keep the wind from getting under it and lifting it, then another rubber seam laid over all that.
So here we sit, with a black rubber roof, and what I would have expected to be the worlds hottest attic.
Not.
The attic is now cooler than the 2 main floors below it, and about as cool as the basement. This cannot be, but none the less is. I give credit to the foam board, but that may not really be right.
Being rubber, it's quite repairable. I've got tape and patches and genuine Firestone rubber contact cement, which is sticky as all get out.
So I'm very happy with the job. Wife is thrilled and that's a very good thing.
z31maniac wrote: Cool, but wrong thread. Have a nice day.
what a nice guy!
The foam is creating a buffer. It is stopping the conduction heat from moving through the roof and radiating into the attic space. There is probably a small airspace below the roof deck- very important.
SVreX wrote: The foam is creating a buffer. It is stopping the conduction heat from moving through the roof and radiating into the attic space. There is probably a small airspace below the roof deck- very important.
If I can figure a way to re-roof my in-laws house, it would be great. But they have these nice little glass blocks in a few places on their concrete roof.
The Caribbean sun just bakes the house, though. Insane baking.
And whatever I can find also needs to be hurricane proof.
Suggestions for tropical flat concrete roofs?
DILYSI Dave wrote: I've wondered about a different kind of roof. first, you have a traditional roof. Asphalt shingles or whatever. Then, a 2-4" air gap, then a metal roof. The thought is that air gap would a) insulate and b) allow the hot air under the metal to rise to the ridge vent. I've seen a similar idea installed in attics, but this would actually be on the exterior.
Obviously this would cost something like 3x a typical asphalt shingle roof system, which is why you might not have seen anyone doing this :). Also, there would be no purpose to putting shingles underneath a metal roof, because the metal is providing the weather resistance. There are systems that use this principle though. One would be a cold roof, basically you install a set of battens above the first layer of roof sheathing to provide an air gap, install another layer of roof sheathing, then your roofing material of choice. This keeps the entire roof the same temperature, so it controls ice dams in colder areas.
I can't find the link right now, but there is a company that makes SIP roof panels that have a built in air gap grid on the top side of the roof panel, below the sheathing layer. The effect is the same as what you're saying, but in a much easier to install and more economical way :).
In reply to Josh:
also wouldn't this mostly be accomplished by installing a radiant barrier on the underside of a normal asphalt shingle roof?
Strizzo wrote: In reply to Josh: also wouldn't this mostly be accomplished by installing a radiant barrier on the underside of a normal asphalt shingle roof?
A properly installed radiant barrier under asphalt shingles would include an air space and a second sheathing layer, so it's basically the same thing. If you're just shingling directly over a radiant barrier it can't work as designed, the barrier needs an air gap to function.
I would think that a white roof would take a home that is like 89% efficient up another hundredth of a point or so. My home is approx. 2% efficient so that is way down on the list.
I think the move toward mandating lighter colored roofs has a lot more to do with managing heat island effects in densely built areas than it does with the individual performance of the buildings with the light roofs. The only time that a project I have worked on specified a light colored roof, it was more of an effort to game the LEED rating system than it was to make the building more efficient.
In reply to Josh:
ah, yes, thats what i meant. i'm not familiar with the radiant barrier installation process, so i wasn't suggesting a non-standard installation. not on purpose at least
If someone is trying to sell you radiant barrier under asphalt shingles they're probably planning on doing it wrong, radiant barrier is supposed to be used under roofing that already has an built in air gap like clay tile or corrugated metal.
Funny thing about all this talk, I think I am actually going to end up doing almost what Dave said when I re-roof the only section of my house that isn't slate. It's only about 25x20 worth of roof, but currently it's a non-vented roof with asphalt shingles. I'm currently planning to leave the asphalt in place, install furring strips on top, then go over that with metal. But that's at least a year and a few thousand dollars from now :).
An aside: after last year's winter, I've seen more than a few flat-roofed buildings having pitched roofs installed. Just trusses over the flat roof, no thought for extra storage. They're doing it so their flat roof won't collapse as so many did up here in Ct over the past winter.
triumph5 wrote: An aside: after last year's winter, I've seen more than a few flat-roofed buildings having pitched roofs installed. Just trusses over the flat roof, no thought for extra storage. They're doing it so their flat roof won't collapse as so many did up here in Ct over the past winter.
Almost always a bad idea.
If they are actually trusses and the load is bearing directly on the outside walls, OK.
They are usually rafters, and include bracing which adds load to the original roof. I'm working on a project now where the additional roof load to the original over-stressed roof caused a major structural failure and near roof collapse.
It can be done, but is usually done wrong.
Josh wrote: If someone is trying to sell you radiant barrier under asphalt shingles they're probably planning on doing it wrong, radiant barrier is supposed to be used under roofing that already has an built in air gap like clay tile or corrugated metal. Funny thing about all this talk, I think I am actually going to end up doing almost what Dave said when I re-roof the only section of my house that isn't slate. It's only about 25x20 worth of roof, but currently it's a non-vented roof with asphalt shingles. I'm currently planning to leave the asphalt in place, install furring strips on top, then go over that with metal. But that's at least a year and a few thousand dollars from now :).
You are technically correct. Radiant barriers needs an air space.
However, the attic is plenty of air space. They can be installed very simply on the underside of the roof decking and/or rafters with the reflective side down and function fine.
I thought we were talking about conditioned attic spaces. I was anyway. That's how the foam roof panels with integrated airspace that I referred to are used. I agree that the attic is the airspace if it's unconditioned. However, installing the barrier directly under the shingles over the sheathing is nonfunctional. Maybe I read the sentence wrong, but that's what I thought strizzo was referring to. It certainly wouldn't be the first time someone installed it that way :).
SVreX wrote: If there were enough interest, I would consider a road trip to do testing on a circuit of multiple houses. Do you have several friends that might be interested? 10 houses worth of testing might be worth a trip to OK, or anywhere else.
I'm interested. Headed south anytime soon?
I would make the trip for several houses. Gainesville is pretty close- I know I'll be there in Oct. 
I need to double check licensing- FL is weird.
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