class A chimney though rubber roof?

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Archer39

Feeling the Heat
Sep 23, 2009
287
Pottstown PA
What is the best way to seal the chimney when going though a rubber roof. The roof has very little pitch with silver roof sealer on top of the rubber. There appears to be a single layer of rubber over the wooden frame. Sorry for the lack of technical terms I am no carptenter.
 

Sleepy

New Member
Jan 23, 2008
70
Western Pa.
Call a roofer who does rubber roofs-preferably the original installer.

Use a metal roof flashing made by the manufacturer of your class-A pipe to maintain clearances to combustibles.

Have the roofer seal the flashing.
 

webby3650

Master of Fire
Sep 2, 2008
11,019
Indiana
There is usually foam or fiberglass insulation under the rubber. It is also unusual to find rubber roofs with roof coating, are you sure there is rubber on your roof? Is this a mobile home, addition, barn, house?
 

Ronmbucket

Member
Oct 18, 2009
23
se pa
Gently burn the silver coating off of the rubber around the perimeter to be flashed.Call a roofer and ask for scrap rubber to flash your chimney. Cut the rubber into 12 inch strips and torch the backside of it and secure a skirt around the perimeter of your chimney.Make sure the corners are wrappped tighly and the rubber skirt extends onto the flat roof surface six inches.Bleed out all edges with a torch and trowel.Seal the top edge at the brickwork with roof cement and fabric. If its a metal chimney (stack),buy the proper metal flashing kit and follow the directions.Imbed the metal base flashing in roof cement. Nail the base to the roof.
Run roof cment and fabric over the edges and incompass the nails. Or spend $150 bucks and hire a pro.
 

begreen

Mooderator
Staff member
Nov 18, 2005
87,146
South Puget Sound, WA
Calling Hog to the front desk. Someone is trying to bounce a roof question off of ya.
 

Beetle-Kill

Minister of Fire
Sep 8, 2009
1,849
Colorado- near the Divide
Have to disagree on a few previous posts. Rubber roof usually is E.P.D.M- EPDM for short( I will Not spell it.) You need specific adhesives, for specific applications. Trust me, I've installed them in the past, and am having a battle with a "roofing company" right now on improper installation. The silver stuff will degrade the integrity of the material quickly, and roofing sealant/ tar will eat it up even quicker. Yellow glue for a subsrtate(metal)-to EPDM adhesion, Black glue( or seam tape)- for an EPDM-toEPDM adhesion. Edges could be adheased, or mechanically fastened. Do a search on the WEB for "EPDM installation", you'll find more than you wanted to know. As a plus, it's pretty resistant to anything coming out of a flue pipe IMO
 

Beetle-Kill

Minister of Fire
Sep 8, 2009
1,849
Colorado- near the Divide
Meant to write- Yellow glue for a substrate(metal)-to EPDM. I've used "Mulehide", and "Firestone" EPDM in the past.
 

Hogwildz

Minister of Fire
Beetle is correct, rubber roofing is EPDM.
What the poster is describing is either a tar (hot roof) or modified bitumen (torch down, and some are cold adhesive applied.
Hot roofs usually have either "slag" (small volcanic stone) on it, or are coated with a black asphalt coating.
Modified bitumen usually is coated with the aluminum coating (silver coating). Easy way to tell if its a modified roof is the seams are 3' apart. Hot roof although applied in overlapping plys of felt layers, are flood coated on top afterward with more tar, or have slag laid down over the flood coat.
If is is modified bitumen, you should let a professional roofer that does modified do the flashing. Torch down can be dangerous, as you literally torch the roofing and then lay it in place fusing the flashing to the roof. Many roofers who don't do it enough and have enough experience, overheat it, and although it looks great, the asphalt layer becomes thinner, and the membrane inside can either start to show through, or even if not, the thinning of the asphalt layers will cause it to prematurely fail &/ or crack early in it's life. If not heated enough, it will not seal properly, and any pin holes will end up as leaks. Torch down is not as easy or properly installed as many roofers who haven't done it for years & miles of it think it is. And I have heard many ill informed roofers call it rubber. Modified bitumen is not rubber.
If its a hot roof, the roofer may muck & tape it in, but that not last very long. Some roofers flash hot roofs the same as modified flashings, as described with slit fingers. But I never used 12" at each slit, that will not give you enough curve or bend around the flashing. Its a two step flashing. a long strip with approx 3" fingers sliced every inch or two the entire length along one of the long sides. Then it is heated along with the roof membrane and the fingers go on the roof surface and the uncut portion wraps around your metal roof flashing. it overlaps 4-6" or so once it wraps around onto itself. Then a bullseye, which is a patch with a hole cut out enough to lay over the metal flashing and yet tight over the fingers and lays flat, covering the fingers and extending past them by a minimum of 3", I usually do about a foot all the way around.

With a true EPDM rubber roof, they will use an uncured rubber flashing which is BLACK (rubber to rubber &/or rubber to metal) glued to the metal flashing and worked and formed down onto the rubber roof surface.
Yellow glue is for rubber to substrate only. Which would be decking, insulation, masonry etc. Never for rubber to rubber. My credentials are/were Carlisle, Goodyear, Firestone, trained & certified when I was still roofing.
Put down miles of both torch down, hot down,, cold applied modified bitumen, EPDM, Hypalon (which honesty is junk) hot tar, if it covers flat roofs, I polly used it.
Rubber lasts forever, but you will have to redo the flashing anywheres from 10 to 20 years later. The rubber field will last forever. Modified will last about 10 years, if not properly maintained less. If kept coated and maintained, could last longer. Tar depends on how many ply's and how well it was installed and maintained. I have seen 40+ year hot roofs in great shape.
Sorry to ramble, roofing is one thing I know very well ;).
CHeck for seams in your roof every 3' apart, I am betting you have a modified bitumen roof. And that is no one you want to try and flash yourself.
Actually, any of these typw roofs are really not for a DIY job.
 

Hogwildz

Minister of Fire
I just noticed where you are Archer. Take some photos of the roof if you can and post them.
If in need, I can come down and check it out for you. Pottstown aint really that far. A couple hours or so from me.
 

Archer39

Feeling the Heat
Sep 23, 2009
287
Pottstown PA
Hog, thank you fir your help. I will take pictures and post them when I get home. If I remember correctly from the last time I was on the roof the seams were further the a few inches apart and it is for sure is covered with the silver roof coating and no stones.
 

Archer39

Feeling the Heat
Sep 23, 2009
287
Pottstown PA
Hogwildz said:
I just noticed where you are Archer. Take some photos of the roof if you can and post them.
If in need, I can come down and check it out for you. Pottstown aint really that far. A couple hours or so from me.
yes I am just a few mins from the other nuke plate here in PA.
 

Archer39

Feeling the Heat
Sep 23, 2009
287
Pottstown PA
I ran out of day light today to take the pictures. I will take them tomorrow.
 

Archer39

Feeling the Heat
Sep 23, 2009
287
Pottstown PA
I did not take any pictures but the seams are indeed 3 feet apart. What should i expect to pay to have a roofer come in and install the flashing? Is there anything i can i can do to make it quicker for roofer?
 

Hogwildz

Minister of Fire
Archer39 said:
I did not take any pictures but the seams are indeed 3 feet apart. What should i expect to pay to have a roofer come in and install the flashing? Is there anything i can i can do to make it quicker for roofer?
Not much you can do in the way of prep work aside from knowing exactly where you want it to go, and making sure there is a clear path between any roof trusses/rafters etc.
Definitely sounds like modified. He will have to heat up the aluma-coat, and scrape it off for the new flashing to adhere properly.
Do you have the metal flashing for it already? If so all he need to do is cut the hole, center the base flashing, secure it with either roofing nails or screws depending on what the deck is made of. I would go with screws as they don't have a chance to back out and work their way through the modified. Then he will flash it in with some modified. A whole new roll is not needed as he will most likely only use no more than 6 foot worth if that. Most roofing companies have scraps laying around. Back when I was roofing, I would have charged about $100.00 to $150.00. If the person was an ass and had cash, I'd charge $200.00. But that was for me to do it on the side, and have the materials on hand already. A company may charge more.
Call a few local roofing companies in your area. MAKE SURE THEY HAVE MODIFIED EXPERIENCE!!!!!! Have them come take a look and give you a quote.
It would be helpful if you knew what was under the modified, usually a base sheet it is torched down to, and usually a 1/2" fiberboard insulation. Then the decking, wood, metal, planks etc.
If you have an attic or access space, look up and see what the decking is made of. Id there is a vent up there or other penetration that you can pull the top off and see in that may also give you an idea of what is there as far as fiberboard etc. Otherwise he may take a plug or cut a small hole to determine this. Let us know what kind of quotes are coming in. I have a long project list going on here, but if your really strapped, I may be able to help.
I still have a torch, and a bar-b-q tank will be plenty for that. And I may be able to get some modified scraps of my old company I worked for. They are in Lansdale.
What is the diameter of the flashing you have? what is the size of the roof portion (square flat part)? how tall is it?, make sure it is made for flat roof. There should also be a storm collar that came with it (metal ring).
If you are prone to tall snow loads on that roof, might have to build up a curb to raise it up and set it on.
 

Archer39

Feeling the Heat
Sep 23, 2009
287
Pottstown PA
Hogwildz said:
Archer39 said:
I did not take any pictures but the seams are indeed 3 feet apart. What should i expect to pay to have a roofer come in and install the flashing? Is there anything i can i can do to make it quicker for roofer?
Not much you can do in the way of prep work aside from knowing exactly where you want it to go, and making sure there is a clear path between any roof trusses/rafters etc.
Definitely sounds like modified. He will have to heat up the aluma-coat, and scrape it off for the new flashing to adhere properly.
Do you have the metal flashing for it already? its on order now If so all he need to do is cut the hole, center the base flashing, secure it with either roofing nails or screws depending on what the deck is made of. I would go with screws as they don't have a chance to back out and work their way through the modified. Then he will flash it in with some modified. A whole new roll is not needed as he will most likely only use no more than 6 foot worth if that. Most roofing companies have scraps laying around. Back when I was roofing, I would have charged about $100.00 to $150.00. If the person was an ass and had cash, I'd charge $200.00. But that was for me to do it on the side, and have the materials on hand already. A company may charge more.
Call a few local roofing companies in your area. MAKE SURE THEY HAVE MODIFIED EXPERIENCE!!!!!! Have them come take a look and give you a quote.
It would be helpful if you knew what was under the modified, usually a base sheet it is torched down to, and usually a 1/2" fiberboard insulation. Then the decking, wood, metal, planks etc. I made a hole on the inside of the house where the chimney will be and there is wood decking then all i can see is black between the planks..
If you have an attic or access space, look up and see what the decking is made of. there are vents (assume they are to allow to heat escape) in the roof that i should be able to take off and get a better view of whats in the space. Id there is a vent up there or other penetration that you can pull the top off and see in that may also give you an idea of what is there as far as fiberboard etc. Otherwise he may take a plug or cut a small hole to determine this. Let us know what kind of quotes are coming in. I have a long project list going on here, but if your really strapped, I may be able to help.
I still have a torch, and a bar-b-q tank will be plenty for that. And I may be able to get some modified scraps of my old company I worked for. They are in Lansdale.
What is the diameter of the flashing you have? what is the size of the roof portion (square flat part)? how tall is it?, make sure it is made for flat roof.the flashing i have on order is made for a flat roof. here is a link to the flashing http://www.hartandcooley.com/chimney/all_chimney.htm. My uncle works for a company that sells hart and cooley so i got a great deal on the stuff. There should also be a storm collar that came with it (metal ring).
If you are prone to tall snow loads on that roof, might have to build up a curb to raise it up and set it on. i don't know about snow loads this will be my first winter in this house.
 

Archer39

Feeling the Heat
Sep 23, 2009
287
Pottstown PA
here are some pictures looking though the roof top vent.

Picture006.jpg


Picture010.jpg


Seam

Picture003.jpg


Area on roof where it will come though

Picture004.jpg
 

Hogwildz

Minister of Fire
Yeap, thats modified. It can be one of 3 types applied. Torch down, hot down, or cold applied. Doesn't look like cold applied, which is goo, cause its garbage.
Most likely torch down. Or you would see tar that would have ran & dripped between the plankers.
I am surprised they did not use any insulation or fiberboard. Is there any insulation between the roof rafters?
Sounds like your all set, now get an experienced torch down modified roofer up there and your set.
If your going to recoat the patched area with alumacoat, wait a few months before coating. You want the surface of the new patch to weather and release any resins etc. Otherwise the alumacoat will prematurely peel off.
Should be a fairly easy job. As long as you have the hole centered, and he centers the base flashing decently, he can install that prior to your pipe running through. The you can install the pipe after he is done. Will be easier for all involved is the base flashing is installed and flashed in first. Keep us informed. Have you gotten any price quoted yet?
 

Archer39

Feeling the Heat
Sep 23, 2009
287
Pottstown PA
no quotes yet i have a few numbers of people i am going to call tomorrow. This is may be a stupid question but i will ask anyway. When the roofer drills the hole for the chimney to go though is this where it has to be framed on all four sides? If so should it be framed out before the flashing is installed? I really don't have access to the attic space to frame it out.
 

Hogwildz

Minister of Fire
Archer39 said:
no quotes yet i have a few numbers of people i am going to call tomorrow. This is may be a stupid question but i will ask anyway. When the roofer drills the hole for the chimney to go though is this where it has to be framed on all four sides? If so should it be framed out before the flashing is installed? I really don't have access to the attic space to frame it out.
Yeap that is the time to frame it out, if you can't get to it from below.
Depending where the existing rafters are, he may have to cut more of the roofing & decking away to gain access to installing the framing.
No big deal, but will call for a larger patch after all is done & ready to flash. And more cost.
 

Archer39

Feeling the Heat
Sep 23, 2009
287
Pottstown PA
I had one roofer come out and take a look so far. He quoted 580 to drill the hole and seal the flashing. I called 3 other places with no return phone call. I think 580 is a little high don't you?
 
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