Smooth vs. granulated

So I’m beginning to study the world of BUR. Little overwhelming, but interesting. Seems clear that there can be big advantages over single plys.

Under what circumstances would it make sense to choose a smooth APP cap over granulated? It will then have to be coated which seems like unnecesary work.

What do you flat guys think of Johns Manville products?

Thanks for all your input. I’m sure this is the beginning of a long line of questions. :mrgreen:

There have been many instances when a smooth membrane was the best fit:

When doing multi-plied system: When you do a double or triple layered modified bitumen system, you want the membranes to weld together. The layers under the cap (the cap is the top layer exposed to the elements) need to be smooth in order to bond together 100%

Price: Sometimes the customer will opt to save some on labor and coat the roof himself after we are done. Many people have more time than money, and this is something they can do themselves. Unfortunately, we cannot warrant the roof for anything other than membrane installation, since the customer is altering the roof after we leave.

Installation: Smooth is less likely to get fudged via the apathetic installer. You can’t watch everyone at all times, and unfortunately this can be an issue for a guy just showing up to collect a paycheck that doesn’t really care about his work, your customer, or your company’s reputation.

I’m sure if I think about it, more reasons will come to mind, but I’m not gonna think any harder about it. Those are the three that come to mind.

talked to a guy today who said he’s had experiences with the seams popping on granulated. Doesn’t adhere as well over granules.

It doesn’t adhere as well if you don’t adhere it properly. We have 20 year old granule surfaced modified bitumen roofs that have zero issues. We know how to do it though.

The specification requiring removal of the granule surfacing at over laps is a remedial spec due to the lack of proper installation. I guess many idiots could not get the proper heat on the seams to achieve the proper seal. Too much heat and you burn the sheet to smithereens. Too little heat and you don’t squish the granules out. Just the right amount of heat and you’re Goldilocks.

I consider granule surfaced BUR to be the culmination and successful integration of yesterdays material with today’s technology.

Think about it…the granules are basically miniture ballast that protect the membrane. The membrane replaces asphalt and is better undeniable. The application process (whether cold or hot) is ancient…liquid based.

It’s like 90lb on steroids + tar & gravel.

As far as I’m concerned, for smaller work, it’s the best system out there. Simple, reliable and super fast when done with an experienced crew (I, by myself, with an inexperience laborer layed 42 rolls in one day). I can’t say enough good things about it.

I remember 90lb roofs that lasted up to 40 years.

I’d be happy today to get 12 trouble free years out of an SBS Roof (but expect and see them going past 15 easily).

A properly installed granule surfaced roof will be unmovable 5 minutes after you’ve laid it (especially with cold applied adhesive). Once it stick, you have a few minutes to play with it if you have to adjust it, but once it’s set, that’s it. It’s done. I’ve found that a thin application of adhesive with good coverage is all it takes.

Honestly, I’ve seen contractors go overboard and hand seal seams with trowel grade mod bit, but that’s when it begins to curl after a few years because instead of the membrane sticking to membrane, it’s just laid in a bed of cement that gives after a while because it’s being used in an application it’s not meant to be used for. Again, a 1/4" notched trowel to leave behind just a little extra on the seams and laps (that squeezes out when stepped out) and a squeegied field has given me worry/maintenance free roofs.

But that’s just my own personal experience…other regions/application & methods might have varying degrees of success.

Granule surfaced cap sheet will last longer and require no maintenance (continual coatings after installed) and I believe provide better protection for the membrane. I think that coated smooth surfaced cap sheet (whether silver or white) might be better at reflecting u.v. rays and possibly heat, but the studies are all over the place for the past 15 years that I’ve been keeping an eye on it.

2nd gen, I think what you are saying is that with a granulated sheet, you trowel on a small amount of adhesive before you torch it?

Actually, I don’t torch it. I personally don’t like torching. Never have. It’s concept never made sense to me. When everybody jumped on the torching bandwagon, I laid back and while I didn’t make a ton of money back then, today, I don’t have to go back and replace roofs that are failing miserable and need to be completely torn down to the deck to be re-done. But that’s just me.

I use a cold-applied method (like tar of old, but it’s an adhesive/glue).

You apply it with a squeegy and trowel the seams and laps with the same adhesive (basically just leaving behind a slightly thicker coat, but not so thick that it doesn’t allow the material to stick to itself).

It’s holding strength is phenomenal.

**A brush consistency cold process asphalt adhesive for SBS modified bitumen single ply membranes. Its high adhesive qualities provide excellent substrate adhesion and strong lap bonds. The manufacturer of this adhesive expects that this product will be used by professional roofing contractors who will employ generally accepted roofing practices in their use of this material.

What kind of surfaces does this Bulldog work on?does it have to be plywood/OSB

It’ll stick capsheet to base sheet.

It’s even worked well over existing 90lb roofs.

So what you’re saying is that since you didn’t install any, you don’t get to go back 20 years later and re-do them? :slight_smile:

The whole concept behind torching modified bitumen is to get a hot welded asphalt waterproofing membrane without the need for a kettle, hot setup, and hot roofing crew.


So what you’re saying is that since you didn’t install any, you don’t get to go back 20 years later and re-do them? :slight_smile:

The whole concept behind torching modified bitumen is to get a hot welded asphalt waterproofing membrane without the need for a kettle, hot setup, and hot roofing crew.[/quote]

No my own work.
I have gone to replace other’s torch down jobs.
In other words, I never worry about callbacks
for torch jobs because I don’t do them.

Nor do I worry about higher insurance rates.
And I don’t have to worry about burning anything down.

There’s a lot that I don’t have to
worry about by “not” torching a roof.

Plus, Cold Applied requires so much less set up and
equipment and has far less potential of liability.

It’s worked for me for 2 decades.
Still works. No need to fix it if it ain’t broke.


Not to mention that I can apply about 4 times
as much material when I’m using cold applied.


drop me a pm and I can answer a lot of your questions, especially if you are inquiring about commercial moreso than residential.

I also don’t have to worry about burning anything down, but thats cuz we don’t burn anything down.

What do you mean you can apply about four times as much material using cold?

What are the inherent problems you are encountering with torch down? We don’t have any problems with it. Lots of success.

Cerberus, just post it up in here… share the wealth.

What do you mean you can apply about four times as much material using cold?[/quote]

I can lay out 1 roll of cold-applied SBS in about 5 minutes from positioning to completion. That means, laid out, walk away, done.

If you’re asking me, it’s not my problems, but problems of customers by contractors that did poor jobs for them. Membrane came back up, peeled up, overtorched, burnt membrane/granules left bald, granules come off upon stepping on hot capsheet, curling seams, cracking, falling from parapets, not bled well enough, yada, yada, yada.

Never had any of those problems with CA (cold applied).

CA’d membrane requires far less skill to apply.
I can train up a laborer in one day to get it right.
With torching, I’d be taking chances.

Like I wrote before, far less liability issues and
faster application with less special tools needed.

A squeegy, a pair of trowels and a knife of course.
A helper that can walk the length of the roll spreading the adhesive while I work the seams and laps.
BAM! Roll down! LOL

i know you’re a professional, 2nd Gen, so please realize that I am discussing and not arguing.

I don’t have the issues you mention with torchdown.

Maybe cuz we are experienced, as I have seen the problems you mention a multitude of times. I have also seen problems with cold process materials.

I know with cold applied, you will usually have to let the rolls rest in the sun sop as to relax from the rolled shape they take on in the roll, so this seems (maybe I am wrong) that it would skew the five minute application time a bit.

I love the torchdown. I have installed thousands of rolls of it over the past 20 years, and most of these roofs are still on. It is definitely an industrial specialized process, and this is probably why most do not do it right… lack of proper training, hence lack of proper understanding.

I bet if you got to doing it on a modified/BUR crew, you would dig it in high production mode too.

I was just watching GAFs video for tri ply SBS and they said on slopes greater than 1"/foot to run the rolls parallel with the slope. Can this be right?

Yep :smiley:


Yep :D[/quote]

What is the reason for this?

Slippage. I like to bias the sheet ever so slightly as well.

No! Of course not! :slight_smile:

I have here in New York.
I’ve never seen a torch job that didn’t fail prematurely here.
Could be a regional thin.
Or, it could be that Im just used to laying out a roof
and walking away from it leaving it maintenance free.

Me too…on roofs improperly installed.
Most of the problems I’ve seen have been from using too much adhesive or from not trusting the product enough.

I don’t apply cold applied roofs in weather that isn’t agreeable with the membrane. I’ll wait it out and get them down in 40 degree+ days with direct sun. The adhesive remains fluid up to 40 degrees “below” zero last I read. Even in cool weather, once it sticks, it’s stuck.

“That”, I have no problem with believing.
Under perfect conditions (base layer, properly vented and insulated deck, etc…), I’m sure it gets the job done.

And round here, I know for a fact most don’t do it right.

I’ve used it for small jobs and I love to use it in situations where I need to custom flash a protrusion.

I’ve just had a 100% track record with cold applied SBS and that’s sold a lot of jobs for me. I’ve had literally no callbacks on any of my SBS jobs (outside of maintenance…gutter/drain clearing, etc…).

Plus, I really like the way it is “alive”. I’ve gone on roofs I’ve done after years and they’ve conformed to the roof nicely. Can’t say I’ve ever actually seen it, but I imagine the capsheet flexing and moving with the roof throughout the seasonal changes.

I love the look of a well torched roof especially before it’s coated. You can tell the craftsmanship of the applicator by how consistent the bled laps and seams are and by how the pattern of the burn on the top of the cap sheet.

I just happen to rock & roll with cold applied SBS.