Insulation Sprayed On Underside Of Roof Deck

[incognito]

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[incognito]

So much mis-information...

I live in Brevard County, Florida, the home of the Florida Solar Energy center. Radiant barriers are among the MOST effective and least expensive methods of reducing your energy bills.

A radiant barrier can be laid on top of rolled or blown in insulation, on the FLOOR of the attic. The reflected heat is exhausted by the normal convection caused by the soffit vent to ridge vent mode, and has NO effect on shingle temp. There MUST be a space between the roof and the barrier for the barrier to be effective.

Read Allan Edward's post again. He is correct, regarding the type of insulation in question, known as Icynene I believe. It encapsulates the attic, and does away with the necessity of ridge venting and soffit vents. It is a significant upgrade in price (I paid $10,000 for my 4000 sq.ft. house OVER the cost of blown in/rolled in insulation.) However, the FL Solar Energy Center (an independent, NON-tree hugging type of institution) predicts a less than 10 year recoup in energy savings. Along with my metal roof, my attic never gets hotter than 85-90 degrees on the hottest Florida summer day.

 

[Mr Rex]

Not all radiant barriers are on the floor of the attic etc, as many plywood/osb manufacturers now have sheet goods with the radiant barrier already attached. Radiant barrier faces down on the roof, faces out on the gables etc.

Heres one:

http://www.gp.com/build/product.aspx?pid=1398

 

[incognito]

Mr. Rex, I agree with you that it seems likely that that type of installation would certainly raise the roofing temperature significantly more than the 3-5 degrees which is expected by more traditional radiant barrier installations.

Further reading discloses that the barrier is most effectively installed in warm climates by attaching to the bottom of the roof trusses (NOT the sheathing) with a vented and exhausted space between the sheathing and the barrier. In colder climates, it is best installed on the floor of the attic, on top of the insulation.

Lastly, radiant barriers would generally NOT be used with the icynene foam insulation systems. The one exception would be like my house, where you have a metal roof which acts like a radiant barrier.

 

[Mr Rex]

From the link:

Q: Can the usage of Thermostat® Radiant Barrier Sheathing damage my shingles?
A: The Reflective Insulation Manufacturers Association (RIMA) has published Technical Bulletin #103 which reports that in peak summer conditions, the temperature of asphalt shingles is increased only an average of 2 to 5 degrees F over non-radiant barrier roof sheathing. This level of temperature rise is not significant and many shingle manufacturers have indicated that it does not affect their warranties.

 

[Cigar]

CertainTeed is probably the largest composition shingle manufacturer, this is from their warranty:

Inadequately Ventilated and Non-Ventilated Decks
Any shingles applied to inadequately ventilated or non-ventilated decks, other than the shingles and deck systems described in the section titled "Insulated Decks and Radiant Barriers," are subject to a reduced limited warranty period of ten (10) years and do not qualify for SureStart Protection. SureStart Protection and the Warranty Period applicable to the shingle are available if C.ertainTeed determines that the shingle damage was caused exclusively by a manufacturing defect that is unrelated to the inadequate roof system ventilation.

Insulated Decks and Radiant Barriers
Certain Teed's Umited Warranty, including SureStart Protection, will remain in force when its fiber glass shingles are applied to roof deck assemblies where foam insulation is prefabricated into the roof deck system (often called "nallboard insulation") , where insulation is installed beneath an acceptable roof deck system, or where radiant barriers are installed, with or without ventilation, directly below the deck. Acceptable roof deck surfaces must consist of at least 3/8" thick plywood or 7/ 16" thick Oriented Strand Board (OSB) and slopes must be 2:12 or greater. If a different deck surface material will be utilized, please contact CertainTeed's Technical Services Department for assistance. (See the following important restrictions.)

The design professional is responsible for ensuring: I) the proper quality and application of the insulation and/or radiant barrier, 2) the provision of adequate structural ventilation and/or vapor retarders as determined to be necessary, and 3) that all local codes are met (particularly taking into account local climate conditions). Special attention must be taken if cellular foam, fiber glass, cellulose insulation or other highly permeable installation will be used in an unventilated system, or if the insulation/rafter or insulation/joist planes may create an air leak that could lead to moisture transmission and condensation problems. All these important factors and decisions, while not the responsibility of CertainTeed, are critical to assure proper deck system performance.¹

It's obvious that there is no warranty if a "design professional" is not involved in specifying and inspecting the installations, a design professional is a licensed architect or engineer.



¹ http://www.certainteed.com/resources/GeneralAsphaltShinglesWarrantyEnglish.pdf

 

[Mr Rex]

CertainTeed is probably the largest composition shingle manufacturer, this is from their warranty:
It's obvious that there is no warranty if a "design professional" is not involved in specifying and inspecting the installations, a design professional is a licensed architect or engineer.



¹ http://www.certainteed.com/resources/GeneralAsphaltShinglesWarrantyEnglish.pdf

How hard do you think it is to find a Design Professional on the staff of the folks selling these products?

 

[Cigar]

How hard do you think it is to find a Design Professional on the staff of the folks selling these products?

As a builder of over a half century I've never seen a design professional other than the architect and engineers originally engaged in the construction, and I've never seen one inspect these products. Maybe appraisers, upon seeing these materials, should check and see if the shingle warranties are actually valid?

 

[Mr Rex]

As a builder of over a half century I've never seen a design professional other than the architect and engineers originally engaged in the construction, and I've never seen one inspect these products. Maybe appraisers, upon seeing these materials, should check and see if the shingle warranties are actually valid?

Where do you read the word "inspect" in the literature you posted? Many engineers and architects provide drawings and calculations to be used in a buildings construction and nobody other than the local inspector ever "inspects".

So the "Design Profesional" at "Foam is us" provides construction drawings and certifies that they meet the requirements in the warranty. No big deal.

 

[Cigar]

Mr. Rex:

The design professional is responsible for ensuring: .......

In the real world of construction the architect specifies a product and puts a note in the general conditions something to the effect: "All products to be installed in accordance with manufactures' installation instructions".

The building inspectors' mandate is to inspect to code, they are suppose to require all ES Reports on products, but rarely do, even if they do the ES Reports usually refer to installation instructions but never contain them. Building inspectors are barred from inspecting quality of workmanship, and this can be a big issue in all exterior envelope products, here is a recent article on foam workmanship problems.

That is new construction, now think of all the con-men running around selling vinyl windows, retrofit insulation, foams, blown in rotten newsprint, and radiant barriers stapled in attics, they seldom even get permits.