Best long term insulation and a some other issues
I have a west (back) wall and my roof also directly lines up to take the full force of the afternoon sun with no shade. The heat in my house in Houston is atrocious. My back wall is that cheap fiberboard that got the manufacturer a class action lawsuit and I’m going to replace it. I want a long term solution that will justify the cost whatever it is.
My current plan is to put Hardie Plank in for the soffit and fascia. The lower part of the other three walls are brick. The house was built in 1979 and is about 1,450 sq. ft with a vaulted ceiling in the living room that is against the back wall. I know there is a little insulation between the ceiling and the roof but if it were to be replaced, it might have to be done through the roof and if so I’d llike to use something better than fiberglass but don’t know the best thing to do.
Additionally, I’m about to replace my roof and I’m looking at a 40 year or lifetime shingle. All the contractors told me I’m wasting my money but the labor is a one time payment and the difference between a 30 yr. roof and 40 is less than $600 for GAF Elk. I don’t yet have a quote on the lifetime shingles. I’d like some support that installed and vented properly, the GAF Elk shingles are appropriately priced and will hold up long enough to be cost effective for their longer life. If GAF Elk and the other manufacturers are lying about the life of their forty year and longer shingles, please tell me.
I’m considering (but not inclined) to put a new roof deck with radiant barrier and am wondering how effective they are when installed on or as the back of the decking, and if there is a more cost effective and/or better way to do the roof. Part of my consideration for the new deck was the abundance of nail holes, by way of the two roofs being removed, compromising the installation, which, as I said, I want to last. My homeowners association won’t allow anything better than asphalt shingles.
This is not an area where I have any great expertise and I don’t have a lot of confidence in contractors’ having either my best interest at heart or being sufficiently knowledgeable about state of the art heating, cooling, insulation and efficiency options.
I do have a little knowledge of insulation and hoping there’s something better than polyisocyanurate, polyurethane, or polystyrene. Can microspheres be cost effective? I want to do this *once* and I’d like to do the best job possible, even if I need to make my back wall, thicker/deeper. I plan of replacing the windows and perhaps using fewer. I have five standard windows on that wall (not counting the back bedroom) viewing only my back yard and want to get good advice.
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Replies
Gary,
Most roofing experts who have looked into asphalt shingle warranties agree that warranties are marketing programs designed to sell shingles; they do not represent actual predictions of longevity.
The manufacturers know that these warranties are rarely invoked. When they are, the warranties generally only apply to the original homeowner (who has usually moved in 7 years), only apply to materials and not labor, and are pro-rated according to elapsed time.
So called "microspheres" (a paint component) are a scam. You can read more about the scam here: 'Insulating' Paint Merchants Dupe Gullible Homeowners.
If you are re-roofing, you have an excellent opportunity to improve the thermal performance of your roof. I recommend installing a thick layer of rigid foam insulation (EPS, XPS, or polyisocyanurate) on top of your existing roof sheathing. This can be topped by another layer of sheathing, with or without ventilation channels between the foam and the top layer of sheathing.
You can also buy a product called "nailbase" which is a sandwich of rigid foam and a top layer of sheathing; some nailbase manufacturers make panels with integral vent channels.
By the way, Elk's warranty allows hot-roof installations. In other words, if you choose to install new shingles without any ventilation channel, Elk will still honor their warranty.
As a homeowner in the Houston area for over 25 years (mainly in the NW Copperfield area), I feel your pain.
If your subdivision allows it, you might put on the white (energy star rated) shingles that are available. It effectively lowers the attic temp by reducing the absorption. Remember as much insulation above the the ceiling you can put in is good, but make sure you have good ridge and soffet vents that have a clear ventilation path. Power vents are sold, but I found ridge vents, and possibly the round 'cyclone' type vents that spin from the air rising helps tremendously. -- This is from personal experience with several roofs over the years in the Houston area. Whatever 'warrantee' you get, the real life of the roof is 1/3 to 1/2 of the specified life. The Elk shingles are what I used on my last roof. They did nicely.
On the siding, I like the idea of put a good paint job on it, then put a secondary outer skin that is vented on the bottom and top to allow natural convection air flow. But still insulate your wall behind it as well as you can afford. I would consider painting the wall of the building with an aluminum (reflective) paint before putting on the outer skin (painting the area that can't be seen).
I agree the old T111 siding that is really pressed cardboard in nature, was trash. It must be caulked well, kept dry, and painted to keep the surface more often than anything else. Eventually I scummed to my wife as she wanted vinyl siding so we did it and I stopped fighting the T111. But it was still there under the vinyl.
Consider planting some tall plants that will shade the wall in the summer that is heat tolerant. We used wax leaf legustrum, and even had some loquat trees that helped. The Loquats will attract bees in the season (you have been warned!) but the fruit is nice and tart to eat, at least from ours!
Best of luck...
Any time you hear "most experts agree", you can be sure you're getting propaganda and not information.
Of course it's true that a shingle warranty is not a prediction of the longevity of the product, because that depends on location (climate), color, orientation, installation, substrate quality, amount of ventilation, and roof pitch. But warranty length is usually directly proportionate to the weight of the shingle, and shingle weight is a good indicator of durability (all other things being equal).
In Houston, a white roof will significantly outlast a dark one, as well as dramatically reducing solar radiant gains and AC costs. But a white metal or tile roof will not only outlast a shingle roof, it will offer even more reduction in cooling load.
Thanks guys. Quite fortunately it seems, GAF Elk has decided to provide a two month window to get a NON-prorated 50 yr. warranty on their lifetime shingles. It seems like this is too good to pass up, provided they stay in business, but since they've been around over a hundred years and are the largest in the country, it's probably smarter to count on that than to let such an opportunity pass.
So now I'd like to know some more about this "secondary outer skin," since that could be effective faster than would hedges or trees. Because the sun comes right over the top of the house, no matter how tall the plants get, they'll only provide protection after the sun goes behind them, which would be around 4:00 pm or later, but still, that would help. It will just take time for them to grow.
I'll have to get with the homeowner's association to find out how light a shingle I can put on my house. I've already had a woman tell me that I don't want white paint on my house. ;-)
As I mentioned, the homeowner's association won't allow anything better than an asphalt roof, so metal, clay and slate are out of the question.
I am looking to find out more about the under shingle insulation mentioned by Martin. That sounds like it might really help. I'd like to lower the attic temp so that I can better utilize it for storage without destroying everything with heat.
I appreciated Robert's remark regarding propaganda and that's why I'm here. I'm old enough to know that a money motive significantly shapes, flavors and colors the "facts" one gets from someone who's selling something. There are still a lot of questions that I have in a lot of areas.
Gary,
Roofing color is the most important factor in reducing solar radiant gains. After that, good roof venting (1:150 SF ratio, top and bottom), and an underdeck radiant barrier can significantly reduce summer attic peak temperatures.
Insulating under the new roofing will only maintain higher summer roofing temperatures and shorten the life of the shingles. Better to strip the heat with ventilation and prevent transfer with a radiant barrier. Add insulation to the attic floor, instead.
To see if I understand you...
You're saying that radiant barrier below the shingles, on either side of the decking, doesn't reflect heat back into the shingles, but Martin's recommendations for "nailbase" or a similar insulating product will?
Please spell it out where I can't misunderstand. If these products are bad for asphalt shingles, do those who sell them instruct their potential customers that they are not for use with asphalt shingles?
While we're at it, I've recently heard from several sources, including GAF-Elk, that GAF-Elk has *clearly* stated that "radiant barriers won't void the GAF-Elk limited warranty against manufacturing defects." It took me all of one second to picture a homeowner wanting warranty replacement and GAF-Elk responding, "Yes, your radiant barrier didn't void our manufacturing defects warranty, but your radiant barrier destroyed our shingles. That's not a manufacturing defect issue. Our shingles were manufactured properly and are not defective. The radiant barrier that you added under your roof reflected heat back into the shingles and aged them prematurely and that's why they're damaged. That's an excessive heat issue brought about by the reflecting of heat by the radiant barrier back into the shingles. We offer no warranty against damage caused by anything that you might add to your house that causes damage to our shingles. Our warranty is solid and we stand behind it. It's just that this isn't a manufactured defect -- it's damage caused by excessive heat brought about by the installation of a third party product. That's not our fault or our liability."
Can anyone else see GAF-Elk or any other shingle manufacturer doing this type of thing? I'd like to think that they more integrity, but I'd like to think that about all the companies that are in business, but I can't. I've seen too many screw people behind verbiage deliberately chosen to make the customer think one thing, but when the company explains it (not until warranty service is needed of course), they have an explanation akin to the difference I've just described. Seemingly viable, but definitely deceptive. We've all heard too many stories of insurance companies doing all sorts of things at claim time completely inconsistent with their attitude, demeanor and words when they were selling the policies.
I found on GAF-Elk's website that they will give a 50 year NON-prorated warranty if I have their lifetime shingles installed between now and July 31, 2010. My contractor, who is an authorized installer for them, doesn't trust them to honor the warranty and says there is no way the shingles will last. My answer was that it all boils down to the integrity of the company. He's afraid that 30 years down the road, they're going to say it was an installer problem or find some other issue to avoid replacing the roof that he says everyone knows won't last and he doesn't want the quality of his work impugned.
I'm hoping that GAF-Elk thought this through and is quite willing to replace the few roofs where full compliance was met and receipts were kept, and of course, my whole motive is money, but that's entirely reasonable since it's my money that I'm spending and the offer is from GAF-Elk. I'm not "tricking" them into offering me something. It was their idea.
Gary,
Your wrote that you have a "a vaulted ceiling in the living room" with "a little insulation between the ceiling and the roof." I recommended the use of rigid insulation on top of your roof deck, under your shingles -- with or without ventilation channels above the insulation (your choice).
I disagree with Robert's statement: "Insulating under the new roofing will only maintain higher summer roofing temperatures and shorten the life of the shingles." If you choose to omit the ventilation (which can be provided with vented nailbase or site-built ventilation channels between the foam and the sheathing above the foam), your asphalt shingles may be warmer than in a vented application. But roof orientation and shingle color matter far more than ventilation, and are more important factors in shingle longevity than ventilation.
Robert implies that shortened shingle life will be the "only" effect of the foam. But the foam will also provide insulation -- it will significantly slow heat flow through your roof assembly. Considering the problems you are discussing, that's important. I'm not quite sure why he's disdaining the use of exterior insulation as a possible solution.
Gary,
If you're that paranoid about warranties, then ignore them and buy the best roofing shingle you can afford.
Radiant barriers cannot be installed on top of the roof deck under the shingles. They work only with an adjacent air space. Their purpose isn't to reflect heat, but rather to prevent radiation of heat to another surface (such as the floor of the attic).
I didn't notice your mention of the vaulted ceiling in the living room. In that area, you may have no choice but to add exterior roof insulation, but I would not advise doing that without an exterior vent channel.
Since your concerns are summer radiant heat gain and longevity of your roofing, putting unvented foam board under your roofing will slow down the normal conductive losses through the sheathing and raise shingle temperature. But those downward conductive losses are what overheats the attic (and hence the house), so it's important in your climate to vent that heat away with continuous soffit and ridge vents.
Using an under-deck radiant barrier along with ventilation meets both your concerns. It prevents solar radiant transfer to the attic floor and house but encourages conductive transfer through the sheathing to the air below it, which will then exhaust through the ridge vent and reduce attic temperatures.
But Martin and I agree that roofing color is the most important variable.
I'm not paranoid about warranties. Actually, I think GAF-Elk's offer is quite timely and beneficial, that is, If they are integrous, and I'm inclined to think they will be, especially if I'm very clear to them that I'm going to do everything they want me to do so they won't have any reason to tell me, down the road, that something is amiss. I stand to get two roofs for the price of one.
Additionally, I'm quite happy to spend the small increase involved in using all their products, and getting their 40 point inspection to confirm that everything is up to snuff and I also intend to get their input on your (the two of you) suggestions about the insulation because I don't want them to have the slightest inclination to search for a reason to not stand behind their 50 year non-prorated warranty. I'm tickled pink at the prospect of paying for a roof once and not worrying about it for 50 years.
Regards,
I forgot to mention that my intention is to use Hardie-Plank perforated soffit and ridge vents and because of the shape of my roof, I think the ventilation will be excellent, provided there is the space between the living room (largest room in the house, of course) ceiling and the roof. I think there is and that will be confirmed at some point, or we'll look at how to fix the problem. The afternoon heat is really terrible. That's why I was wondering about why microspheres haven't gained more acceptance. I guess it's material cost, because, as I think I said, microspheres are 1.5 times more insulative than polystyrene and they don't lose those properties, like all the polys do.
I have a GAF-Elk Warranty, its not worth the paper its written on. A month after I paid $51,000 for a new roof it began to leak around the chimneys. They said it was because my Chimneys were old. When the roof was replaced, they did not replace any rotten wood around the chimneys. First time chimneys leaked in 30 years. Vent leaks, that is because I had a painter, paint the trim. Forget Warranty, go with local roofer you trust.