Please post questions about anything having to do with roofing

[Kenton H. Shepard, CMI]

Originally Posted by tspargo

"Racking" your shingles @ installation gets my vote!

Super common failure.. if you see a 3-5 year old roof and the patterned curling of shingles... they were "Racking" their shingles, meaning bending them to allow for an installation in a straight up and down manner, rather than in a standard typewriter / stair type install.

Tim

The National Roofing Contractor's Association told me that they thought no manufacturer allowed racking.
Owens Corning "Berkshire" shingles actually require it. The CertainTeed Applicator's Manual includes directions for racking installations and GAF doesn't recommend it but will allow it.

EVE OVERHANG.
The CertainTeed Applicator's Manual calls for 3/8" overhang at the eve if there's drip edge installed and 3/4" overhang if none is installed.

[Tim Spargo]

I think the thinking is/was, 3 tabs were OK.. but nothing else. In general, I would be concerned if I saw any roof being installed in this method...

Except the Berkshire I suppose, good find. Sounds like you're doing your homework.

Tim

[Kenton H. Shepard, CMI]

Originally Posted by tspargo

I think the thinking is/was, 3 tabs were OK.. but nothing else. In general, I would be concerned if I saw any roof being installed in this method...

Except the Berkshire I suppose, good find. Sounds like you're doing your homework.

Tim

I think it's not allowed in laminate shingles, but it's hard to make general statements about anything. Every time I think I've found something definite to say, it seems like an exception always appears.

If racking is required by one major manufacturer, described as an acceptable method by another, and described as acceptable but not preferred by another, yet described as unacceptable by the foremost non-profit roofing trade organization... what should a course on Roofing Defect Recognition recommend that home inspectors tell their client if they find racking? Feel free to make suggestions here, anybody, but I'm thinking that a good narrative describing the fact that attitudes concerning racking vary and disclaiming any results of racking is the answer.

That's what's going into the InterNACHI Narratives, although it'll be described a little more elegantly.

[Tim Spargo]

I think that is key... results of racking etc..

Tim

[Kenton H. Shepard, CMI]

One of the best sources of information on comp shingles I've found are the Shingle Applicator's manual and Shingle Technology Manual, both available for free from CertainTeed. Order them here.

[Kenton H. Shepard, CMI]

As far as underlayment goes, it's also a crucial part of the shingle's fire rating.

[Marcel R. Cyr]

Originally Posted by kshepard

As far as underlayment goes, it's also a crucial part of the shingle's fire rating.

Kenton, I am not questioning your research here, I am trying to satisfy my curiosity.

Where did you get that information that underlayment is part of the shingle's fire rating testing?

I see no mention here;

ASTM E108


Significance and Use
The test methods described herein are intended to provide a basis for relative comparison of roof coverings.

The test methods include simulated fire exposure to the outside of the roof coverings, and, where applicable, a determination as to whether the fire performance characteristics of the roof coverings will be adversely affected by prolonged exposure to rain.

These test methods measure the surface spread of flame and the ability of the roof covering material or system to resist fire penetration from the exterior to the underside of a roof deck under the conditions of exposure.

These test methods also provide criteria to determine if the roof covering material will develop flying burning material, identified as flying brands, when subjected to a 12-mph [5.3-m/s] wind during the simulated fire exposure tests.
These test methods do not necessarily illustrate the expected performance of roof coverings under all actual fire conditions, but they do provide a basis for comparing roof covering materials when subjected to fire sources that are described herein.

These test methods do not provide any basis for determining the fire resistance characteristics when exposed to a fire originating in the building to which the roofing material is applied.

The test methods described herein involve calibrating the test equipment using a calibration deck inclined at a slope of 5 in. per horizontal ft (0.416:1).

The tests described herein are performed on test decks inclined at slopes up to and including 5 in. per horizontal ft. The severity of the test exposure decreases as the slope of the test deck decreases below 5 in. per horizontal ft.


1. Scope


1.1 This fire-test-response standard covers the measurement of the relative fire characteristics of roof coverings under simulated fire originating outside the building. It is applicable to roof coverings intended for installation on either combustible or noncombustible decks when applied as intended for use. The following test methods are included:

1.1.1 Intermittent flame exposure test.
1.1.2 Spread of flame test.
1.1.3 Burning brand test.
1.1.4 Flying brand test.
1.1.5 Rain test.
1.2 Three classes of fire test exposure are described:
1.2.1 Class A Tests are applicable to roof coverings that are effective against severe test exposure, afford a high degree of fire protection to the roof deck, do not slip from position, and do not present a flying brand hazard.

1.2.2 Class B Tests are applicable to roof coverings that are effective against moderate test exposure, afford a moderate degree of fire protection to the roof deck, do not slip from position, and do not present a flying brand hazard.

1.2.3 Class C Tests are applicable to roof coverings that are effective against light test exposure, afford a light degree of fire protection to the roof deck, do not slip from position, and do not present a flying brand hazard.

1.3 The values stated in inch-pound units shall be regarded as the standard. Values given in brackets are for information only.

1.4 This standard is used to measure and describe the response of materials, products, or assemblies to heat and flame under controlled laboratory conditions, but does not by itself incorporate all factors required for fire hazard or fire risk assessment of the materials, products or assemblies under actual fire conditions.

This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

1.5 The text of this standard references notes and footnotes that provide explanatory information. These notes and footnotes, excluding those in tables and figures, shall not be considered as requirements of this standard.
</SPAN>
2. Referenced Documents



D1227 Specification for Emulsified Asphalt Used as a Protective Coating for Roofing
D2178 Specification for Asphalt Glass Felt Used in Roofing and Waterproofing
D225 Specification for Asphalt Shingles (Organic Felt) Surfaced With Mineral Granules
D226 Specification for Asphalt-Saturated Organic Felt Used in Roofing and Waterproofing
D227 Specification for Coal-Tar-Saturated Organic Felt Used in Roofing and Waterproofing
D250 Specification for Asphalt-Saturated Asbestos Felt Used in Roofing and Waterproofing
D2626 Specification for Asphalt-Saturated and Coated Organic Felt Base Sheet Used in Roofing
D2898 Practice for Accelerated Weathering of Fire-Retardant-Treated Wood for Fire Testing
D3018 Specification for Class A Asphalt Shingles Surfaced with Mineral Granules
D312 Specification for Asphalt Used in Roofing
D3158 Discontinued 1984; Specification for Asphalt Saturated and Coated Organic Felt Used in Roofing
D3378 Discontinued 1985; Specification for Asphalt-Saturated and Coated Asbestos Felt Base Sheet Used in Roofing
D3462 Specification for Asphalt Shingles Made from Glass Felt and Surfaced with Mineral Granules
D4442 Test Methods for Direct Moisture Content Measurement of Wood and Wood-Base Materials
D4444 Test Method for Laboratory Standardization and Calibration of Hand-Held Moisture Meters
D450 Specification for Coal-Tar Pitch Used in Roofing, Dampproofing, and Waterproofing
NFPA 256 Tests of Roof Coverings
UL 55A Materials for Built-Up Roof Coverings
UL790 Tests for Fire Resistance of Roof Covering Materials


Index Terms

burning brands; classification; flying brand; intermittent flame; rain test; roof coverings; roof deck; spread of flame; ICS Number Code 13.220.50; 91.060.20; 13.220.50; 91.060.20; 13.220.50; 91.060.20

DOI: 10.1520/E0108-07A

ASTM International is a member of CrossRef.

ASTM E108 (Fire and Flammability Standards



And here it states that underlayment is suitable for Class A,Band C roof products.

http://www.certainteed.com/resources...electBroch.pdf

Marcel

[Kenton H. Shepard, CMI]

[quote=mcyr;477714]Kenton,

...Where did you get that information that underlayment is part of the shingle's fire rating testing?

I see no mention here;

ASTM E108

Page 20 of the CertainTeed Shingle Applicator's Manual, Marcel. ASTM provides the standard, but the UL performs the testing to ensure that shingles meet the standard. Apparently testing with the underlayment in place is part of their protocol.

I just sent this query off to the UL:

"Am I correct in thinking that roofing underlayment installation is required for asphalt composition shingles to perform according to their respective UL fire-rating?".
I'll post their answer

[Marcel R. Cyr]

[quote=kshepard;477752]

Originally Posted by mcyr

Kenton,

...Where did you get that information that underlayment is part of the shingle's fire rating testing?

I see no mention here;

ASTM E108

Page 20 of the CertainTeed Shingle Applicator's Manual, Marcel. ASTM provides the standard, but the UL performs the testing to ensure that shingles meet the standard. Apparently testing with the underlayment in place is part of their protocol.

I just sent this query off to the UL:

"Am I correct in thinking that roofing underlayment installation is required for asphalt composition shingles to perform according to their respective UL fire-rating?".
I'll post their answer

Thanks Kenton, you are doing a superb job at this.

Marcel

[Kenton H. Shepard, CMI]

Thanks Marcel. I found a little more information, althogh no reply from the UL yet.

Class A fire rated shingles will retain their fire rating even when applied wthout underlyment as long as the plywood deck is at least 15/32" thick or the non-veneered deck (read- OSB) is at least 1/2" thick.

If the plywood deck is less than 15/32" thick, the fire rating is lowered to "C".

3/8" is the minimum roof deck thickness required for a shnigle to have a fire rating.

Inspectors will not know the shingle fire rating, but can tell by the deck thickness whether the thickness of the sheathing may affect a fire rating.

[Ed Fako]

A wonderful thread and I compliment the thoroughness of your responses.

Since I just read through the 3 pages, I will just add on my .02 cents on one of the more recent inquiries.

Racking:

What problems can occur?

The most obvious and immediate answer is the straight vertical pattern, which stands out more prominently than the stair stepped method.

But, the real and more significant problem, is that many applicators will omit the 4th nail on the next succeeding course of shingles, because they will not take the time to lift up the offset tab and slow down their rythm of installation.

Therefor, the improper nailing aspect which is so common comes into play.

Additionally, if they do lift up the offset tab to install the nail in the lower course, that tab will retain its memory from being so vigorously lifted out of position and then being immediately nailed down.



Now, I have a question that the true answer seems to be eluding me.

Short Circuiting of Attic Ventilation?

Although many manufacturers point out this mysic air flow occurence, are there any fluid dynamic or other types of studies that substantiate the actual airflow that occurs when different vent products are included in the same confined attic area?

To be more specific, lets consider a home that has sufficient continuous Intake Ventilation, but for exhaust, they have a continuous Ridge Vent System, even the ones that contain an exterior baffle.

Add exterior wall gable vents to the mix.

What actual studies have been done to verify that the attic air flowage is truly being short circuited?

Further, even if the actual flowage is proven to take different exit paths, ie; being short circuited, what proof in temperature readings and RH factor readings have been documented to imperically state that this scenario proves inhibitive to the total attic ventilation system and the affects of a properly vented attic and roof?

Ed

[Ed Fako]

By the way, I wanted to thank everyone who liked my solutions that I posted on the thread over at JLC regarding eliminating an ongoing ice dam effectively.

I heard back personally from the OP, that the Magnesium Chloride flakes and soluble solution with water did the trick much more rapidly than he would have thought possible otherwise.

Ed

[Kenton H. Shepard, CMI]

Originally Posted by Ed Fako

Now, I have a question that the true answer seems to be eluding me.

Short Circuiting of Attic Ventilation?

Although many manufacturers point out this mysic air flow occurence, are there any fluid dynamic or other types of studies that substantiate the actual airflow that occurs when different vent products are included in the same confined attic area?

To be more specific, lets consider a home that has sufficient continuous Intake Ventilation, but for exhaust, they have a continuous Ridge Vent System, even the ones that contain an exterior baffle.

Add exterior wall gable vents to the mix.

What actual studies have been done to verify that the attic air flowage is truly being short circuited?

Further, even if the actual flowage is proven to take different exit paths, ie; being short circuited, what proof in temperature readings and RH factor readings have been documented to imperically state that this scenario proves inhibitive to the total attic ventilation system and the affects of a properly vented attic and roof?

Ed

The CertainTeed Shingle Applicator's Manual has a great section on venting attics with more detailed information on flow than I've found anywhere else. It includes illustrations of the different flow paths through a gabled attic when gable vents align with and are perpendicular to prevailing winds.
It also includes the difference between continuous ridge vents with and without baffles- a big difference due to the Bernoulli effect.

I've not found anything based on formal studies about mixing ventilation systems. I've heard individual inspectors and some ex-roofing contractors say it's bad, but I always like to see a formal study before backing statements like that. The info on the ineffectiveness of wind-aligned gable vents surplrised me and what seem like logical assumptions aren't always true.

I believe that continuous soffit/ridge vents have flow path problems not discussed even in this manual, and I'll be adressing that issue in the Advanced Roof Defect course I'm developing for InterNACHI.

Much of CertainTeed's information appears to come from their studies plus those of the University of Illinois, NAHB studies and a couple of other reputable places. They push thier products in this manual, but to a reasonable extent and it's clear that providing information is the manual's priority.

[Ed Fako]

Originally Posted by kshepard

The CertainTeed Shingle Applicator's Manual has a great section on venting attics with more detailed information on flow than I've found anywhere else. It includes illustrations of the different flow paths through a gabled attic when gable vents align with and are perpendicular to prevailing winds.
It also includes the difference between continuous ridge vents with and without baffles- a big difference due to the Bernoulli effect.

I've not found anything based on formal studies about mixing ventilation systems. I've heard individual inspectors and some ex-roofing contractors say it's bad, but I always like to see a formal study before backing statements like that. The info on the ineffectiveness of wind-aligned gable vents surplrised me and what seem like logical assumptions aren't always true.

I believe that continuous soffit/ridge vents have flow path problems not discussed even in this manual, and I'll be adressing that issue in the Advanced Roof Defect course I'm developing for InterNACHI.

Much of CertainTeed's information appears to come from their studies plus those of the University of Illinois, NAHB studies and a couple of other reputable places. They push thier products in this manual, but to a reasonable extent and it's clear that providing information is the manual's priority.

Illustrations are just some persons rendering of what they either perceive to be as a correct flow, an educated assumption or a method to back up previous claims made to establish their credibility. I do tend to lean in their direction more often than not though, but I have conducted several instances of case studies, utilizing "Hip Vents" in several cathedral/vaulted ceiling scenarios which prohibited the usage of more traditional ventilation solutions. So, from that one type of perspective, which goes completely against the standard ventilation suggestions, I find their thinking to be too large of a blanket statement to cover various real life conditions found in the real world.

I have taken their accumulative tests from the 2nd edition through the current 8th edition and can pretty much recite the Air Vent guide, titled, The Principles Of Attic Ventilation booklet by rote memory. (Air Vent formally was a subsidiary of Certainteed, now owned by The Gibraltar Companies)

I was just hoping that you had additional resources besides those that you had mentioned, which I am thoroughly familiar with as well.

By the way, I personally would be very interested in your roofing course and could even advance a pre-published version to a core of roofing contractors for evaluation, if you would be comfortable sharing that.

As a side note, Air Vent is currently conducting their ventilation seminars across several regions of the country.

Here is the information for scheduled dates and locations.
Air Vent Seminar Schedule For 2009, With Free Registration Info

--------------------------------------------------------------------------------

I always try to go every year, not so much anymore for the ventilation seminar, but more for the Question and Answer Section that immediately follows.

Also, I find it good networking to pass out your business card to the other attendees.

It is amazing to me, how FEW Roofing Contractors actually take the time to show up. The majority of the room is filled up with material suppliers staff and architects, plus a few groups of Roofers.

Here is the Registration Form and Seminar Dates and Locations for this years events.

http://www.airvent.com/professional/seminars.shtml

By the way, just for showing up, you get either a free breakfast or lunch, plus a brand new Buck Knife in a sheath.

Hop up from your table immediately when the seminar is done to get yours. I waited because I was still awaiting additional questions and I missed out last year.

Ed

[Kenton H. Shepard, CMI]

Originally Posted by Ed Fako

Illustrations are just some persons rendering of what they either perceive to be as a correct flow, an educated assumption or a method to back up previous claims made to establish their credibility. I do tend to lean in their direction more often than not though, but I have conducted several instances of case studies, utilizing "Hip Vents" in several cathedral/vaulted ceiling scenarios which prohibited the usage of more traditional ventilation solutions. So, from that one type of perspective, which goes completely against the standard ventilation suggestions, I find their thinking to be too large of a blanket statement to cover various real life conditions found in the real world.

I have taken their accumulative tests from the 2nd edition through the current 8th edition and can pretty much recite the Air Vent guide, titled, The Principles Of Attic Ventilation booklet by rote memory. (Air Vent formally was a subsidiary of Certainteed, now owned by The Gibraltar Companies)

I was just hoping that you had additional resources besides those that you had mentioned, which I am thoroughly familiar with as well.

By the way, I personally would be very interested in your roofing course and could even advance a pre-published version to a core of roofing contractors for evaluation, if you would be comfortable sharing that.

As a side note, Air Vent is currently conducting their ventilation seminars across several regions of the country.

Here is the information for scheduled dates and locations.
Air Vent Seminar Schedule For 2009, With Free Registration Info

--------------------------------------------------------------------------------

I always try to go every year, not so much anymore for the ventilation seminar, but more for the Question and Answer Section that immediately follows.

Also, I find it good networking to pass out your business card to the other attendees.

It is amazing to me, how FEW Roofing Contractors actually take the time to show up. The majority of the room is filled up with material suppliers staff and architects, plus a few groups of Roofers.

Here is the Registration Form and Seminar Dates and Locations for this years events.

http://www.airvent.com/professional/seminars.shtml

By the way, just for showing up, you get either a free breakfast or lunch, plus a brand new Buck Knife in a sheath.

Hop up from your table immediately when the seminar is done to get yours. I waited because I was still awaiting additional questions and I missed out last year.

Ed

In assembling information I always seem to run into conflicting theories, sometimes among pretty credible sources, and just have to pick one based on what seems to make sense having looked at a lot of info and with some basic knowledge of building science and physics. In addition to a variety of sources from google, I've looked at Building Science Corp., several national laboratories, info from several inspection schools, various courses over the years, UBC, IRC. and so on.

There's very little new or really complete information. It's like trying to put a puzzle together. Thanks for the Air Vent information.

This is really a roof defect recognition course with a small section on roof ventilation. Be nice to make it short but accurate and informative.