Thread: Torchdown shingle integration

Was inspecting this condominium this week and came across this strange combination. The building was only 4 years old. The torchdown had been silver coated and appeared to be glued down along the edges to Presidential Shingles. The plumbing vents didn't have boots but were wrapped with membrane. Anyone ever seen this type of installation?

//Rick

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I have seen simular roofing systems, it is a good thing just to refer to a professional roofing company that install that kind of system, unless the association hired you, your job is easy, just observe the professional installation, torch represents fire and anytime you are working with fire related repair than you need professionals that can deal with the liability.

Fred Sweezer Sr.
1-562-234-2689
Home Inspections in Long Beach, Los Angeles, Santa Ana and Surrounding Areas | Sweezer’s Inspection Service

Originally Posted by Fred Sweezer Sr

...torch represents fire and anytime you are working with fire related repair than you need professionals that can deal with the liability.

Thanks for making the point, I just added language to that effect to my report comments for torch-down products.

Yes I have seen this application many times in condo work, the soil vent would either need a lead jacket up the pipe and rolled over the top edge and down inside 1 inch, or the mebrane rolls up the pipe and a collar flashing with a draw band with neoprene tape installed above the membrane joint. There are several methods to install soil vents and thats not one of them.

The intersection between the flat and steep pitch would need a metal flashing . Does not meet NRCA (National Roofing Contractor Association) standards. The IBC roofing section even states in in a round about way. if you look into a GAF specifacations manual, all the details are similar to the NRCA.

Many times when they do install the edge flashing, they take manufactured edge flashing for a 90 degree edge and try to mold it to fit from a flat roof to a for instance 9 on 12 pitch which can cause a dam, or they fasten with staples and not roofing nails every 6 inches

Well...

Here's the NRCA detail for that flashing:

http://www.nrca.net/consumer/types/details/mb-18.pdf

it's one of a number of links to common mod bit flashing details at the bottom of this page:

Polymer-modified bitumen sheet membranes | NRCA National Roofing Contractors Association


OTOH here in Chicago I frequently see it done per the OP's picture, and in my experience if done carefully it's seldom a source of leaks unless there has been mechanical damage at the stack or the membrane is generally deteriorated - I report it, but it's not at the top of my list of concerns (compared for example to skylight or roof-top AC and deck installations).

------

That transition at the turn-down is very difficult to do properly, and I've never been able source a "correct" way to do it - if someone else has, I'd really appreciate a link.

Originally Posted by Joseph Ehrhardt

The intersection between the flat and steep pitch would need a metal flashing .

The shingles go up under the metal flashing Joseph is referring to, the single ply (torch down, hot mop, whatever type) goes over top of the metal flashing.

Michael,

We were hired by a condo association to do an inspection before the builder warranty ran out.

Do you have the detail specs for the how the power pedestal should be installed on the roof?


Thanks

//Rick

Originally Posted by Rick Bunzel

We were hired by a condo association to do an inspection before the builder warranty ran out.

Rick,

You also need a fall protection railing at those a/c condenser units because they are that close to the edge of the roof.

I've never had the opportunity to see so many chimneys in a group like that. Is there an issue with how close those chimneys are to one another?

Jerry is correct, units are with in 10 feet from the roof edge you need a rail, also the B-Vent caps that are clustered need to be a minimum of 12" inches from each other.

I've been in roofing industry for 33 years and this is not a new one.
Two issues:
1 The soil stack is not up to "standard and workmanlike" trade codes, as stated earlier it needs to be either a lead flashing or a metal collar, neither of these is present. I have seen this done when impending rain is coming and the flashings are not on the job so they did the best they could in the short time available. The only acceptable deal would be to later go back and install the metal collar flashing and torch it in correctly, not atempt to cover it up with aluminum paint.
2 The edge treatment is joke. Thats a very poor job of integration between shingle and the flat roof. You can get a 135 degree metal flashing at most roofing suppliers to cover this situation. The metal goes down over the base sheet and a layer of torch down ( smooth NOT GRANULATED) This is called the target sheet and only needs to be about 12" wide on the deck. The metal is then correctly nailed into the roof edge staying back from the outside bent edge. The top layer of torch down goes over these and is solidly imbeded in tar onto the target sheet and all the way out to the bend corner but not on the shingle's metal face The metal flange on the flat deck should be in a sandwich of torch down both on it's top and bottom. This is watertight and looks good for sloped shingles providing a clean visual line from the ground and good waterproof integration.
The good news is it would be pretty easy to add it now as the roof looks loose at that perimeter.
The spec: Cut it back about 12", peel off the old edge of the torch down material and do the above target sheet approach. Tie that in well to the old torch and coat it and it should be fine.
You can also add those metal collars to the pipes too. Stick the collar on then just burn off any coating on the old roof ( this will become your new target sheet) around the pipes to get fresh felt exposed. Install a new top (torch) sheet large enough to cover the flange and 6" more on all sides. This will be a new piece over the flange by 6" onto the roof which would be solidly tarred in place.

Jerry,

The AC units were actually more centered in the torchdown area and the shingled slope areas were at least 10 ft. wide. Not sure what OSHA requires but it was about 4 stories up so I was very respectful of where I was moving.

Joseph - regarding the B-vents is there a spec or code I can refer to?

Thanks

//Rick

Originally Posted by Rick Bunzel

Michael,

We were hired by a condo association to do an inspection before the builder warranty ran out.

Do you have the detail specs for the how the power pedestal should be installed on the roof?


Thanks

//Rick

Sorry, I don't think the NRCA has that detail on line - the next time I see it done right I'll take a pic and post it - basically the best method is a hood with a turn down.

IMO, If you are doing this type of work you may want to order a copy of the NRCA "Guidelines for Roof Mounted Outdoor Air Conditioner Installations":

Guidelines for Roof-mounted Outdoor Air-conditioner Installations

Originally Posted by Rick Bunzel

The AC units were actually more centered in the torchdown area and the shingled slope areas were at least 10 ft. wide.

The shingled sloped areas do not count.

Those condenser units were centered? They sure looked like there was almost at the far edge of that flat roof.

Rick, sorry for the delay, what a 3 day weekend.Heres the issue I came up with here in jersey ...theres no direct code wording except install to manufacture specifications per our title 5:23.3.6 NJ Uniform Construction Code. It seems I come across Simpson Vent kit a lot, they will specify a 12" miminum height off a flat to 7/12 pitch and do not address distance between vent caps from each other in their on line specs, but they have email or faxed me stating 12" inches in between caps. I found this out when I came across this problem at a couple condo's that had a negative pressure problems.The mechanical code should specify more detail on this, I have come across wacky airfoil and cyclone related pressures and fixed them by moving, raising and staggering vent pipe and caps.

I've read the first 10-12 replys and you guys are right. Keep in mind the NRCA only makes recommendations based on what the roofing manufacturers say. Every manufacturer has alternate details to every application and the one on the pipe is acceptable if it was terminated at the top. It would need a clamp at the top with butal caulk behind it, or a lead flashing which terminates inside the pipe, or some manufacturers allow you to add a 6 in fabric and cement termination. Any of these would be acceptable.
What you saw as glue is really the modified bituman bleeding out from behind the sheet. That's a good thing and should be visable on every lap at every inch. If it's not visable it may not be heat welded correctly, (this area could be a defect).
The aluminum roof coating (paint) serves two purposes. It protects the laps from weather, keeping them intact longer. It also gives the roof reflective properties and can affect the heating/cooling costs.
The transition between the shingle roof and the low slope roof is totally unacceptable. There are several ways to make this transition. In the N.E. we generally put the metal over the field sheet of roofing, nailing it down so it won't blow up in high wind. Then strip it in with 6 or 9 inch modified Bituman. Mr Webb had a good solution also. The less popular application but also acceptable is to put the field of the roof directly on the metal flange. This way usually leaks after a couple of years.
I hope this helps sorry it was so long. Ross

Originally Posted by Rick Bunzel

Michael,

We were hired by a condo association to do an inspection before the builder warranty ran out.

Do you have the detail specs for the how the power pedestal should be installed on the roof?


Thanks

//Rick

Here ya' go: