Asphalt composition roll roofing?

[sidney alstad]

Came across this type of roofing material at today's inspection. Asphalt composition shingles were utilized except over the front porch roof where it looked like roll roofing was installed. What type of material is this?...is it proper?... I've got some better pictures, but they are too large, maybe I will see if I can re-size and post later tonight.

[Rick Cantrell]

"What type of material is this?"
Looks like roll roofing

"is it proper?"
That depends on the roof pitch, but looks OK as far as I can see.

[Brandon Whitmore]

It may be aggregate covered modified bitumen, or the cheaper asphalt comp. roll roofing. It looks like it is lying fairly flat, so my bet is mod. bit.

[Gunnar Alquist]

Hey folks, on a related note.

Can someone give me a quick visual primer on those types of materials?

Roll roofing
Hot-mopped with a granulated cap sheet
Modified Bitumen
Torch-down

Other than the clearly improper "top-nailed" roll roofing, I cannot tell the difference from one to another.

[Brandon Whitmore]

Can someone give me a quick visual primer on those types of materials?

Roll roofing
Hot-mopped with a granulated cap sheet
Modified Bitumen
Torch-down

I'll try. I don't see many of them. Oregon isn't really a good place to have a flat roof.


Modified Bitumen
Torch-down

Torch- down is slang for mod. bit. Mod bit can be hot or cold applied.


Roll roofing or
Modified Bitumen

Mod. bit. roofing is much more flexible. When you try to tear mod. bit. it doesn't want to tear. When you bend or try to tear roll roofing, it tears like an asphalt shingle would. Plus, roll roofing almost always looks like crap.

Hope that helps a little.

[Gunnar Alquist]

Brandon,

Thanks.

I had kind of thought that modified bitumen was synonymous with torch-down, but wasn't sure. I have been told by a few roofing contractors that torch-down is not used much, at least around here, because insurance companies are reluctant to insure guys with flame-throwers. Huh... imagine that.

I have also been told that the exposure is different with modified bitumen and the granulated cap sheet. One was 30" and the other was 34 or 36. Can't remember any more.

Wish I could say the bad memory was old age, but I have always been like this.

[Brandon Whitmore]

I have also been told that the exposure is different with modified bitumen and the granulated cap sheet. One was 30" and the other was 34 or 36. Can't remember any more.

I really don't know. I'm sure it depends on the manufacturer. I can't say I've ever inspected a BUR with a cap sheet. Mod. Bit. is pretty common around these parts. The roofers have to stand watch with fire extinguishers for a couple of hours after torching the roof.

[Matt Fellman]

My old boss called the composition rolls "chicken coop roofing" - that's always helped me remember the quality versus the other materials.

I struggled to learn the various types of flat roofs for years before I felt somewhat comfortable.... like Brandon says, we don't see many around here. Besides, the only thing you really have to know is that they always leak.

[Tom Roon]

Hard to see very well from the angle of the picture, however, looking at the drip edge type and not seeing any seams, it doesn't look like rolled roofing. The main roofing is using dimension shingles, so I suspect the low pitch area is using one of the sheet goods type. It also looks like the edges may not be stuck down and sealed very well, but from this view, my old eyes can't tell.

[Gary Wilson]

My old boss called the composition rolls "chicken coop roofing" - that's always helped me remember the quality versus the other materials.

I struggled to learn the various types of flat roofs for years before I felt somewhat comfortable.... like Brandon says, we don't see many around here. Besides, the only thing you really have to know is that they always leak.


Any roof will leak if improperly installed, like the one in the picture. It is hard to tell from the picture, but it does look like a modified bitumen system. You could look at GAF (Liberty) or Certainteed (Flintlastic) for a little more product info. This roof is improperly flashed at the perimeter, (who knows how it looks if there is a roof/wall junction) but if the homeowner is lucky it should suffice.

BTW, we don't see much torch down modified here anymore (Wisc). To much liability and the insurance companies sure as hell don't like it! :mad:

[Vern Heiler]

Hard to see very well from the angle of the picture, however, looking at the drip edge type and not seeing any seams, it doesn't look like rolled roofing. The main roofing is using dimension shingles, so I suspect the low pitch area is using one of the sheet goods type. It also looks like the edges may not be stuck down and sealed very well, but from this view, my old eyes can't tell.

I think the pitch is from left to right in the picture. You wouldn't be able to see the seam if I'm right.

I've put down some of what looks like this roofing. The stuff I used was called selvage. The top 6" is not covered with granules and is covered by the overlap that is sealed with roofing cement.

[Mitchell Toelle]

Gary W. said, "This roof is improperly flashed at the perimeter"....

What's wrong with the drip edge flashing? I don't see anything wrong with it.

With a built-up roof covering, modified bit. or the new stick down type modified, they will be a heavy material (the built-up either has a granulated cap sheet or agregate).

Generally the rolled mineral roof covering (chicken coop roofing) is easy to spot because of the way it is applied, ripples, buckles, exposed fasteners, no bedding at seams or dripedge/ flashing, etc. and it is much thinner.

[Tom Rees]

I don't see any seams which leads me to believe it is a built up with tar and gravel top coat. It is very common to see separation at the edges and alligatoring of any exposed asphalt. Because of the nature of these roofs I put this in my reports:

This property has what is called a built-up roof. It consists of alternating layers of impregnated roofing felts and bitumen (asphalt). The roof is finished with a layer of asphalt formulated for weather resistance and a layer of gravel. Built-up roofs can be 2-ply to 5-ply meaning 2-5 layers of felt and asphalt. Built-up 2-ply roofs last 5-10 years and 5-ply roofs 15-20 with periodic maintenance. Because it is not possible to tell how many layers are on roof and because the gravel coating makes it hard to see the roof covering it is recommended that a certified roofing contractor evaluate the roof (before proceeding with any type of sales transaction) and issue a 5 year roof certificate and/or recommend repairs, maintenance and/or replacement of roof.

[Charles Smith]

Here are PIX of modified bitumen and built up roll gravel. Also SPF foam and TPO/PVC membrane

Most Santa Fe roofs are flat as they adopted the Pueblo Revival Style in the early 1900's.

The built up roll that is exposed at the parapet wall area aids in determining age and useful life. The asphalt roll loses granules and the fiberglass becomes exposed. The material becomes brittle, cracks and blisters. The canale drains (SCUPPERS) need additional flashing in and around the canale throat area. Most leaks are around the canales.

The picture shows a cracked area along a parapet. This covering has reached end of life. Twenty years and more is not unusual and is proportional to how well the covering has been maintained.

Multi-ply built up gravel; modified bitumen; spray foam with gravel (fines or aggregate) and TPO/PVC membranes are the coverings used here.

And as was stated previously... the roof covering is only as good as it was installed.... with improper flashing at parapets, skylights, canales, vents and drip edges being the most problematic.

[Jerry Peck]

Pull on a corner of the roofing, it if tears relatively easily then it is organic mat felt roll roofing and is NOT to be left exposed to sunlight, however, if it stretches and is hard to tear then it is most likely modified bitumen, and then you get into application - either hot mop, torch down, or peel-and-stick (aka lick-n-stick :) ).

Organic felt roll roofing will be hot mopped, and should be covered with something to protect it from the sun, such as concrete tile.

[Gunnar Alquist]

Most Santa Fe roofs are flat as they adopted the Pueblo Revival Style in the early 1900's.


Hey, I was just in Santa Fe a week or so ago. Tried to contact Jim, but he was out of town. Too bad I didn't think to look you up. Maybe next time. I always wanted to meet Bart Simpson. :cool:

[Phil Gould]

My neighbors just had new roofing installed on a vintage 6-flat and garages. Is this the cheap roll roofing?

[John Kogel]

My neighbors just had new roofing installed on a vintage 6-flat and garages. Is this the cheap roll roofing?No. It looks like Mod Bit, modified bitumen, or "Torch-on" roofing. If you watched them install it you would see them heat the membrane with a tiger torch, then roll it out, no nails.
It is good stuff and lasts about 15-25 years when applied right.
Cheap roll roofing will have nails exposed or globs of tar covering nails, good for only about 5 years.

[Phil Gould]

Thanks John. Always good to see a post from you. I'm still deciding about that 32' ladder, and am much more thoughtful about telling jokes on inspections.