Heat-reflective decking and other radiant barrier products

Happy Sunday everyone,

Last week one of my customers insisted on my bid including the cost to re-deck his 40-Square roof with Solarbord. In case someone reading is not familiar, the product is basically heat-reflecting foil laminated onto Norbord OSB. The manufacturer's site claims that it stops 97% of the sun’s radiant energy before it can penetrate the attic space.

The beef is that it can save a typical home as much as 17% in annual cooling costs (says brochure). Obviously the big benefit is to us southerners in our fry-yourself-on-the-barbie summers, but it helps hold heat in your home during winter, too.

Has anyone had experience with this product or other radiant barriers? At $15 - $18 a sheet, the HO is going to shell out $3,000 to do this once labor and all the bells are tied on. Isn't there a better option?

Someone mentioned attic ventilation. Scavenging the interior heat in an attic is the method of radiant barrier I am familiar with. Running the interior of the attic. Crowding it to the top plate or tied beam where the junction of the roof connects to the wall top. Either lattice stripping it to the rafter/ truss, crowding it to the rafter/wall area and securing it. Then unifying the junction points of the ridges and hips. I've run collar ties at the scissoring to create A flat ceiling and that allows for the air to cross contaminate to the attic fans. I push fanning and adequate venting. Many homes have soffit vents painted over, gables that could accept motorized units etc. It's all about what the homeowner wishes, vs. what they can afford. They keep hollering green green green. Govt. funding would assist. This is one of the greatest areas that we remove the homes imprint from the earth. Heat transfer done properly is A priceless commodity. I'm not all for cap & trade, forcing homeowners to bring things to A standard, unless we as A nation support it for all. Theirs several other things that I've been looking into, thermonomics for A/C units, hot solar water heaters and such. We could move in the right direction. What we spend on war could make us independent on other countries should we wisely fund proper programs.

Hey, it is a "hobby", isn't it? If you don't know your costs, anything will do as a price.

Same here Rocky. Easy to slip a couple in, in advance.

I do (did) discount it when we did re-decks, or just a lot of sheets on a relatively simple roof.

I think the fellas doing it so cheap are just adding on a couple of sheets to the invoice. Shocking! :unsure:

Twill, $60 is our minimum, for a couple of sheets, if we know in advance, but total resheets we'll bring the cost down. 1x8", ship lap, T$G; 6-$8 per ln ft

Old School Said: If it is reflecting back up, isnt the heat going to the back of the shingle?

Radiant barrier decking does not reflect the heat. It blocks heat movement. The shingle is going to attain a temp dependent on the amount of sun and outside air movement and temp which is its heat source. The source of the heat is not the attic. Aluminum just happens to be an excellent heat barrier- 97% effective; however, it becomes an excellent conductor if anything touches it. That is why there must be an air space behind the decking. I have seen some roofers lay the radiant barrier decking right over the spaced lathe boards on a redeck which made the radiant barrier totally ineffective.

There is a company that makes Aluminum faced underlayment-Polaralum. It is totally useless as a radiant barrier although some roofers sell it as such.

Used to replace plywood for $60 a sheet. Economy (Read: Dumbazz "roofers") has forced it down to $50.

Most of of Hare Brains (shoe salesmen) here are @ $35 or so. They also run their business on $25 an hr.

So...........whaddoIno?

What can you buy for 15-$18 a sheet that is any good? and then you have delivery and installation costs. I would be sell that for 40-$60 a sheet installed, damn girl , better double check those prices. In Phoenix, where it gets a little hot, fewer than one in 50 houses with radiant barrier. If you like selling it, this is a big market for it. :woohoo: :P :kiss:

If it is reflecting back up, isn't the heat going to the back of the shingle?

I have been using radiant barrier decking on all of my redecks since about '02 when the price came down. Since the price of radiant barrier decking today is only about $2 more per sheet, it should be a crime not to use it. Some of my clients reported that before radiant barrier, their AC ran all day and could not even keep the house cool. After radiant barrier, their AC cycled and cooled down the house. All you have to do is test it yourself. Go into an attic with radiant barrier decking and the temp will be only slightly higher than the outside temp. Go into an attic without radiant barrier and you will be dead in a few minutes. Ventilation alone will only bring the temp down a little. But radiant barrier plus ventilation is the ideal. Cooking the shingles is a myth. An object will only get as hot as its molecular structure allows and the amount of heat source it is exposed to. A shingle exposed to the sun will dissipate its attained heat to the outside air. It just will not dissipate into the attic as much if a radiant barrier is present.

If there is no air moving beneath the decking, the reflective barrier will certainly cook the shingles right in place. It will make it worse for the shingles.

It has never been clear to me if these products will fry the shingles. I agree w O/S

The biggest thing is to keep the air moving just beneath the roof surface. That requires total ventilation at the soffits and at the ridge with a baffle to draw the air out at the peak. On a "retro" situation such as you are talking about, I would tear out the old soffits and open them up into the attic space and then install a fully vented aluminum soffit so the air can really flow into the attic. When you install the roof, just make sure to then install a Airvent II ridgevent and make sure that they cut open the ridge to let the air out. If you do those things, it will be cheaper than the foil faced board and the results should be similiar, if not better.

OTOH, if you do install the new board, do the same thing anyway, It will enhance everything.