Thread: liberty sbs self-adhering roofing system

planning some work for later this summer - replacing the roof on a screen in porch. current roof is shingles over felt paper.

picked up a partial roll of liberty sbs self-adhering roofing system. is there any advantage to using that over felt?

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any feedback?

note the liberty is not self healing when punctured with a nail, like the ice and water shield, thus my interest in knowing whether there are any advantages of using it over felt

It's like any roof system, it must be properly installed.

I'm not a big fan of self-adhered membranes, prefer torch down when possible.

That said, if the crew has installed it successfully before, and follows all the manufacturer's install guidelines, and it's applied to a sound deck, and they handle the transitions/flashing details correctly , you should have good results.

Dom.

GAF -Liberty
There are "single", "two ply" and "three ply" systems that range in warranty of 10 and 15 years.

Like Don not great fan of stick down systems though much better than just 100# roll roofing.

I may be misunderstanding what your real question is. Are you tinkling of using the Liberty material instead of 15# or 30# felt then applying standard 3 tab shingle?

Any decent self-adhering (peel and stick) underlayment is better than 15# (Type I) or 30# (Type II) felt.

First and foremost, if applied with any decency at all, it stays down instead of blowing away with the shingles (and, no, those tin tabs and plastic cap nails are not very good at holding down anything that tears easily, and those felts tear easily.

With any decent self-adhering underlayment installed with any decency will mostly keep leaks which get past the shingles from leaking through to the sheathing and through the sheathing.

I cannot think of one good reason not to use a self-adhering underlayment, not even the reason which is most often given as 'the reason' not to use it ... i.e., getting it off is the pits. If it is that hard to get off at re-roofing, then it sticks pretty dang good, doesn't it? Also, if it sticks that well, it can be left in place at re-roofing and either recovered over with another self-adhering underlayment (some allow this) or cover it with felt (which is not very useful) or just reuse it by itself.

Does it make the roofers and inspectors think about what they are doing? Sure. Is that a bad thing?

Originally Posted by Garry Sorrells

I may be misunderstanding what your real question is. Are you tinkling of using the Liberty material instead of 15# or 30# felt then applying standard 3 tab shingle?

Yes, that is what I was trying to decide between.

Using any underlayment that does not seal around the nail will allow water to penetrate to the roof deck and the interior space below.

Non sealing underlayment may shed the water at some of the penetration points as the water moves down between the shingle and the underlayment, but the water will get through other penetration points.

Which is why the shingle that is allowing the water to get to the underlayment may be several feet away from where the water is showing up in the interior space.

Using an underlayment that seals around the nail penetration is superior to plain felt, belt and suspenders concept.

Originally Posted by Garry Sorrells

Using any underlayment that does not seal around the nail will allow water to penetrate to the roof deck and the interior space below.

Non sealing underlayment may shed the water at some of the penetration points as the water moves down between the shingle and the underlayment, but the water will get through other penetration points.

Which is why the shingle that is allowing the water to get to the underlayment may be several feet away from where the water is showing up in the interior space.

Using an underlayment that seals around the nail penetration is superior to plain felt, belt and suspenders concept.

While I agree to all above points, the question was about (basically speaking) - which is better: a) peel and stick; b) felt. The unequivocal answer is that any decent peel and stick is far better than felt.

I misunderstood the OP, thought he was installing a cap sheet or full system, not an underlayment.

Dom.

Morning Joisko. Hope you are in good health and spirits today.

I think Joisko has been subjected to the lack of full material disclosure at the box store level.

From what I understand, and typically/usually that is not much, ha ha ha, SBS (styrene-butadiene-styrene) is modified bitumen. When using modified bitumen to cover a roof surface there are typically/usually 3 approved applications. Hot mopped and hot welded, and cold adhesive applied systems.

I prefer (1) hot mopped, (2) my second choice would be torch welded. (3) Thirdly, cold adhesive but would avoid this application in cold weather.

Joisko, what is the pitch or degree of slope of the roof you are covering?
I ask this because, roofing associations, as well as certified roofers agree, low slope roof decks, slopes below <4/12, should not be shingled.
For one, the suns rays are too direct. This can prematurely affect the life cycle of an asphalt or glass fiber mat shingle. Typically through, glass fiber mat out preforms asphalt mat in warm climates.
Secondly, water can/will defy gravity, water tension, and back up under shingles.

Joisko, Ice/Water Damming is a phrase/term used to explain water backing up under shingles. That is why manufacturers produce ice shield.
Now this might be folk lore or a myth Joisko, but the term/phrase Ice Damming was coined by the continual phase being heard by neighbors associated with its effects on northern home owners roofs shortly after the invention of three tab organic shingles.
"DAM IT Alice!!!" Water is coming in through the new bloody shingles again this spring. I think its the DAM ICE!!! Look at the water on the floor. If I get my hands on that roofer that sold us those shingles, "Bang, Zoom, To The Moon!"
jackie g.JPG
Thus the term/phrase Dam Ice was reversed and elongated to the term/phase Ice Damming we all know today, for obvious reasons, and became a staple term/phase throughout the roofing industry.
Please, don't take my word on that.

If you wish to keep the same look, you can install a rubberized underlay manufactured by Grace water/ice shield.
It self adheres to the roof deck creating a water tight membrane/barrier. As you fasten the shingles the roof deck the rubberized underlaymen, grace water/ice shield, will seal around the nails protecting the roof decking.

Keep us posted.
Best.
Robert

Originally Posted by Joisko

planning some work for later this summer - replacing the roof on a screen in porch. current roof is shingles over felt paper.

picked up a partial roll of liberty sbs self-adhering roofing system. is there any advantage to using that over felt?

Robert,
Joisko was questioning if the SBS was better to use than felt as an underlayment.

I first thought the question was installing over top of felt then understood instead of felt.
Then I thought low slope because of material (SBS) in question.
I do not think that slope is the issue or question. Just an alternative to using felt.

Have been waiting to hear someone chime in on shingle manufacture installation specifications, as they have been written for years, and alternate underlayment materials not mentioned in installation specifications.

Originally Posted by ROBERT YOUNG

From what I understand, and typically/usually that is not much, ha ha ha, SBS (styrene-butadiene-styrene) is modified bitumen. When using modified bitumen to cover a roof surface there are typically/usually 3 approved applications. Hot mopped and hot welded, and cold adhesive applied systems.

From here: GAF | Liberty SBS Self-Adhering Base/Ply Sheet

"
Liberty™ Systems are applied without torches, open flames, hot asphalt, or messy solvent-based adhesives and are suitable for primed plywood decks and many other substrates.
"

It is a 'peel-n-stick' base sheet.

It is designed for use as:
"
Liberty™ SBS Self-Adhering Base/Ply Sheet is a self-adhering roofing membrane designed for use with Liberty™ SBS Self-Adhering Cap Sheet or Liberty™ SBS Self-Adhering Cap FR Sheet to provide long-lasting protection for the low-slope areas of your property.
"

It may, or may not, be used as underlayment for shingles depending on where you are and the shingle manufacturer, along with all product approvals.

Being as its intended use by the original poster is under shingles, and that shingles are nailed down (meaning that no ability to be bonded to what is applied over it is required), it may be suitable for use as an underlayment if the shingle manufacturer approves it as an acceptable underlayment.

Garry, Jerry, I was confused by the narrative, "is there any advantage to using that over felt?"
Thanks.

The reasoning behind my post were options, well that and humor....

Is the slope consider low? <4/12. I would avoid shingles.

Over felt, atop, or instead of felt?

As well, the base layer is for SMS systems.
Am I to take it the manufacturer is selling the modified cold application base layer as an ice/water shield?

The expression "Cap Sheet" the base sheet membrane, selvage, layers and cap sheet for curbs, flashing coping.
I have not installed many. It was near the end of my construction trades carrier. ><35.

Any two or 3 part SBS system finishing layer is a Cap Sheet with selvage sheet...
The selvage sheet is the base layer.

Non perforated #15 felt as a salvage or modified self adhered, I prefer modified selvage.

There are base sheets (first/bottom/underlayment sheet), ply sheets (between the base sheet and the top/finish sheet), and cap sheets (top/finish/what-you-see sheet) ... and dual purpose sheets (such as base/ply sheets) ... and that particular sheet is referred to by the manufacturer as a base/ply sheet - so why try to call it something else?

Just like why say there are hot mop/torch down/cold process when the manufacturer refers to it as self-adhering?

There are self-adhering base sheets and base/ply sheets which simply need a clean broom swept surface to stick to.

In an effort to be accurate.

Base Ply: the lowermost ply of roofing in a roof membrane or roof system.

Base sheet: An impregnated, saturated, or coated felt, placed as the first ply in some multi-ply built-up and modified bitumen roof membranes.

Cap sheet: Granular surface coated sheet, used as the top ply of some build-up or modified bitumen roof membranes "and/or flashing."


CAP SHEET MEMBRANES page 15.

Originally Posted by ROBERT YOUNG

In an effort to be accurate.

Base Ply: the lowermost ply of roofing in a roof membrane or roof system.

Base sheet: An impregnated, saturated, or coated felt, placed as the first ply in some multi-ply built-up and modified bitumen roof membranes.

Cap sheet: Granular surface coated sheet, used as the top ply of some build-up or modified bitumen roof membranes "and/or flashing."


CAP SHEET MEMBRANES page 15.

In an effort to be accurate - there are, as I stated, products which are rated for use as base/ply
sheets, and, in fact, I even quoted the manufacturer in question stating so:
[quote-Jerry Peck]It is designed for use as:
"
Liberty™ SBS Self-Adhering Base/Ply Sheet is a self-adhering roofing membrane designed for use with Liberty™ SBS Self-Adhering Cap Sheet or Liberty™ SBS Self-Adhering Cap FR Sheet to provide long-lasting protection for the low-slope areas of your property.
"[/quote]

Not sure why you keep insisting that you are correct and the manufacturer is not????

Originally Posted by Jerry Peck

In an effort to be accurate - there are, as I stated, products which are rated for use as base/ply
sheets, and, in fact, I even quoted the manufacturer in question stating so:
[quote-Jerry Peck]It is designed for use as:
"
Liberty™ SBS Self-Adhering Base/Ply Sheet is a self-adhering roofing membrane designed for use with Liberty™ SBS Self-Adhering Cap Sheet or Liberty™ SBS Self-Adhering Cap FR Sheet to provide long-lasting protection for the low-slope areas of your property.
"

Not sure why you keep insisting that you are correct and the manufacturer is not???? [/QUOTE]

...Manufacturers do not own terminology.
The post consists of terminology from (2) manufacturers.

Originally Posted by ROBERT YOUNG

...Manufacturers do not own terminology.
The post consists of terminology from (2) manufacturers.

You ... the manufacturer DOES specify the terminology for THEIR products, and THAT manufacturer DOES use the term "Base/Ply Sheet".

You can argue as much as you want about the terminology for THE Base/Ply Sheet under discussion ... but you need to argue with the manufacturer.

So YOU .

Mr. Robert ... just what would YOU call a sheet which is suitable for use as a "Base Sheet" and is ALSO suitable for use as a "Ply Sheet" ... being as you have an objection to the term "Base/Ply Sheet"?

http://www.gaf.com/roofing/commercial/products/modified_bitumen_roofing/self_adhered/liberty_sbs_base_sheet

"Liberty™ SBS Self-Adhering Base/Ply Sheet

Description

Liberty™ SBS Self-Adhering Base/Ply Sheet is a durable, modified bitumen membrane designed and manufactured to meet industry and code requirements. The product is designed for use as a waterproofing membrane and is reinforced with a glass mat, which is coated with a polymer-modified asphalt. Liberty™ SBS Self-Adhering Base/Ply Sheet is a self-adhering roofing membrane designed for use with Liberty™ SBS Self-Adhering Cap Sheet or Liberty™ SBS Self-Adhering Cap FR Sheet ......"

The nomenclature is somewhat about apples and oranges as they hang on a tree.

The Base/ply sheet is part of a system for low slope roofs. There are up to 3 layers as part of the Liberty System. The base sheet is used as the system base, period. I do not find Liberty recommendation as a underlayment for shingles.

Felt is used as an underlayment as it has been for years for non low sloped roof shingles.

I do not think you will find that Liberty or any other manufacture will instruct the use of the base ply sheet as the underlayment for their shingles, with the exception of membrane for first 3 feet.

Calling the Liberty Base Sheet an underlayment goes against their terminalogy pf the product. So, felt is described by manufacture as underlayment. Though we may call the base sheet underlayment since we are suggesting using the base sheet as the equilvent of an underlaymnent it is not technically an underlayment by manufacture's product descriptions

Again much to do about nothing, kinda tomato / tamato . It is going down as an atypical application with shingles.

Originally Posted by Garry Sorrells

... with the exception of membrane for first 3 feet.

Sooo ... it is not to be used as an underlayment because it doesn't say it is an underlayment, but ...

... it may be used asan ice dam underlayment if you so choose ... even though it is does not say it is an ice dam underlayment for the first 3 feet?

I'm missing something there ... please explain.

From here: http://www.gaf.com/Other_Documents/L...ons_Manual.pdf

"LIBERTY™ SBS SELF-ADHERED Roofing Systems Application & Specifications Manual"

On page 24 (file page 25 of 106):

"
Wood Decks–
Plywood
• Plywood sheathing shall be exterior-grade, minimum 4-ply, not less than 15/32" (12 mm) thick.
• Preservatives or fire retardants used to treat decking must be compatible with roofing materials.
• Must be installed over joists not greater than 24" (610 mm) o.c.
• Must be installed so that all four sides of each plywood panel bear on and are secured to joists and cross blocking; the plywood must be secured in accordance with the Engineered Wood Association recommendations. “H” clips are not acceptable.
• Panels must be installed with a 1/8" to 1/4" (3 mm - 6 mm) gap between panels and must match vertically at joints to within 1/8" (3 mm).
• Decking should be kept dry and roofed promptly after installation.
• Knotholes or large cracks in excess of 1/4" (6 mm) should be covered with securely nailed sheet metal.
• When light metal wall ties or other structural metal are exposed on top of the wood deck, cover them with a heavy ply of roofing sheet, such as GAFGLAS® Stratavent® Nailable Venting Base Sheet, extending 2" - 6" (51 mm - 152 mm) beyond the metal in all directions. Nail in place before applying the base ply.
• Attach an acceptable base sheet through flat metal caps or use nails with attached 1" (25 mm) square or round metal caps that have a minimum withdrawal resistance of 40 pounds (178 N) each.
• Tape and staple-fastening systems may be used on wood decks when they comply with local building codes and agencies.

Oriented Strand Board (OSB) Decks
• Only products with the Structural 1 APA rating should be used as a decking material.
• Weyerhaeuser’s Struc-One oriented strand board is an acceptable substrate to receive a GAF roofing assembly. It must be a minimum of 1/2" (13 mm) thick. See plywood deck section for applicable requirements.
"

The attachment of OSB is required to meet the attachment of plywood - "Must be installed so that all four sides of each plywood panel bear on and are secured to joists and cross blocking; the plywood must be secured in accordance with the Engineered Wood Association recommendations. “H” clips are not acceptable."

That is a killer for most plywood and OSB roof decks " ... all four sides of each plywood panel bear on and are secured to ... ".

As the saying goes - the devil is in the details.

Originally Posted by Jerry Peck

Mr. Robert ... just what would YOU call a sheet which is suitable for use as a "Base Sheet" and is ALSO suitable for use as a "Ply Sheet" ... being as you have an objection to the term "Base/Ply Sheet"?

You think the avatar creator could replace the stick with a feather?

I have no objection to a term being used as intended.

To answer you question/s... I have no objection to a term being used as intended.
Garry has the answer. Their terminology. Terminology is a patchwork of terms used by manufacturer's to describe THEIR product installation methods.

As stated in my previous post, ...Manufacturers do not own terminology.


As to your question. When does a dry ply becomes a wet ply for shedding water? It is still a base ply is it not?
BUR roofing system.
A dry ply is incorporated in to the build up roofing system to prevent the Moped PLY's from adhering to the roof deck. Is the dry ply separate of the mopped ply?
As in multi ply systems. There are BUR systems were 5 plys are used.
Which ply is the base ply.
Ply refers to a single (1) of many.

As to a previous post of mine.
#1: Base Ply: The lowermost ply of roofing in a roof membrane or roof system.
In a BUR roof system that would be the dry ply. The single sheet of #15 pound organic felt.

#2: Base sheet: An impregnated, saturated, or coated felt, placed as the first ply in some multi-ply built-up and modified bitumen roof membranes.

#3: Cap sheet: Granular surface coated sheet, used as the top ply of some build-up or modified bitumen roof membranes "and/or flashing."

I hope that helps.

Originally Posted by ROBERT YOUNG

Terminology is a patchwork of terms used by manufacturer's to describe THEIR product installation methods.

Precisely.

Thus when I refer to them referring to it as a Base/Ply Sheet ... there was and is no need or reason for you to dispute it and imply "correcting" it ... was/is there?

Jerry, I was unfamiliar with that/those terms. I was hopen/wishen a good conversation would come out and it did.Garry, Jerry, or Jerry and Garry, much thanks for the conversation. Always helpfully.

PS: Any chances in/of changing that avatar's stick for a feather? You can poke someone in the eye with that stick.

Originally Posted by Jerry Peck

Sooo ... it is not to be used as an underlayment because it doesn't say it is an underlayment, but ...

... it may be used asan ice dam underlayment if you so choose ... even though it is does not say it is an ice dam underlayment for the first 3 feet?

I'm missing something there ... please explain.

It is about the use of the term "underlayment" in product name and product specified use.

The Liberty base sheet is only discussed by Liberty as part of their low slope system. I did not find anything that suggested to use it as an "underlayment" for shingle application.

The typical shingle installation call for "underlayment". If you look at product name/application description you find "underlayment" used.

Now if you wanted to use the Liberty base sheet as an underlayment I would not see any issue in doing so for what you are attempting to achieve in sealing under the shingles. Just that the Liberty product is not called an "underlayment" product by them.

Yes tedious and nit-picking.
It is the difference in saying to someone it will work for what you are trying to accomplish, but it may not meet the specific terminology of what a manufacture states in their installation specifications to meet the warranty conditions for shingle installation.

Hope all that may clear up what I was attempting to convey.

Originally Posted by Garry Sorrells

It is about the use of the term "underlayment" in product name and product specified use.
.
.
Hope all that may clear up what I was attempting to convey.

Garry,

That didn't clear anything up - you said it was not suitable for use as "underlaymet" and therefore is not "underlayment"; you then said it was suitable for use as ice and water shield ... even though it is not "ice and water shield" ...

The same reasoning applies to a proposed use outside its stated purpose, whether that proposed use is underlayment or ice and water shield - either it is or it is not ... for either proposed use.

Sounds to me like you are trying to, as they say "walk it back" without actually taking it back with you. Just sayin' ... I think we have both killed the dead horse ... that horse just ain't gonna drink no water.

The horse wants Tequila.

Liberty base sheet is not called "underlayment" by them.

Originally Posted by Garry Sorrells

The horse wants Tequila.

Liberty base sheet is not called "underlayment" by them.

It's not called water and ice shield either ... so the horse may need a double.