APP over coal tar?


#1

I know its a no no but I have a guy that wants 165 square of app torched over an old coal tar roof.
Its on a 2/12 with no penetrations and pea gravel on a ball T gyp deck.
The pea gravel can be broomed off clean.
Its not how I want to do it but on a job this size if I add base or insulation ill lose it. He will find someone thats willing to do whatever he asks as long as he pays.
He doesn’t own the bldg but his lease says he has to maintain it himself so he wants it cheap.
I know we flash with asphalt onto coal tar but this is extreme.
How long do you think it will last?
A week?
A month?
A year?


#2

Lets forget for a second about the 2:12 slope, and everything else. My question is why in the world would you even consider torching to coal-tar? You like getting pitch-burned or something?


#3

No different than moping it down or tearing it off I figure. Id keep the flame on the roll.
Believe me Its not my idea Ive never tried it before and wouldn’t. But if he insists on it and I don’t have to warrant it what the heck.
Id back nail it with something to help keep it in place due to the pitch and the pitch.
I just think the odds of it sticking good are probably slim and if it does I cant see it lasting a long time.
I just wondered if any one had seen it tried.


#4

It has been a while and I may be wrong but I thought coal tar and modified were incompatible materials.

If this is the case you should insist on a slipsheet to separate the coal tar from the modified.

Or you could inform the customer in writing that this is not an approved application and shift responsibility to them.
A bottom of the ladder warranty so to speak…
He may change his mind when he sees it in writing, and allow you to do it right.

Good luck.


#5

No no and no!!! isn’t there a product out there made by sopra or another manufacture for this type off install? MODI will not last or work[imho] any chance this guy is indian or arabic sounds familiar.


#6

Allied Signel used to make a pitch base modified.


#7

Yes they did, but that is gone!

When I was roofing we used the old Derbigum membrane for flashings on the Nissan Truck Manufacturing Plant’s coal-tar roofs. Don’t know how well that worked out long term.

As for the person who voiced a concern about compatibility. You are correct, however, asphalt and coal-tar’s incompatibility really comes into play in a kettle. It isn’t so bad that you mop one over the other, but you NEVER want to use an asphalt kettle to heat coal-tar, or vice-versa.

As for BornaRoofer, I wish you luck and recommend that you buy yourself a couple pillow-cases. Cut eye holes in the pillow cases and slip them over your head. You may look like a klans man, but it is better than exposing your face to all the fumes from the re-heated pitch. Also, if the existing coal-tar is some of the old-style pitch, I predict you are going to be hating life.

Personally, this is one job I would pass on unless I had to have it to pay the bills. Even then, I’d probably farm it out.


#8

I don’t know about reheating the pitch and if its worse than mop smoke or tear off but id imagine I have coal tar in my dna by now I have eaten and breathed in so much of it over the years. I’m not really worried about getting burned my skins like redwing boot leather. Theres a cream thats like a peel mask that works ok and tube socks with finger holes over the arms help a lot to.
I may have him talked out of doing it this way we will see. Either way I wont be responsible for it if he does and it will be in writing.


#9

if you can just sweep the gravel off clean you are not talking about ctp.pitch envelops the gravel @ about 72 degrees f. if you think torching to pitch is no worse than mopping it or tearing it off you have a life lesson coming!pitch and modified are not compatible. the creosol in the pitch will eat the modified up after time and it will crack(alligator).let me know when you torch it …i want to know how your eyes fell then.


#10

[quote=“Cerberus”]

**As for BornaRoofer, I wish you luck and recommend that you buy yourself a couple pillow-cases.

Cut eye holes in the pillow cases and slip them over your head.

You may look like a klans man, but it is better than exposing your face to all the fumes from the re-heated pitch. **

Also, if the existing coal-tar is some of the old-style pitch, I predict you are going to be hating life.

Personally, this is one job I would pass on unless I had to have it to pay the bills. Even then, I’d probably farm it out.[/quote]

The only thing I did when we actually did use pillow cases on a real mean Pitch TO in the dead of winter, was add ski goggles to the pillow case with the foam cushion to seal against the cotton.

That worked pretty good and we were lucky it was a pretty much all white neighborhood. The National Guard Armory at Midway Airport in Chicago.

Ed


#11

Roofboss, on old pitch roofs the flood coat wears and the gravel starts to come loose. More with pea gravel than slag but after 50-60 years it can happen.
Anyhow the gravels loose and it is pitch. The gutters are half full of it.
If you know that torching to pitch is worse have you done it? I have done it on tie ins and it didn’t seem bad although thats not 160+ rolls either…


#12

the pillowcase could have many uses including hiding your identity.LOL


#13

[quote=“BornaRoofer”]I don’t know about reheating the pitch and if its worse than mop smoke or tear off but id imagine I have coal tar in my dna by now I have eaten and breathed in so much of it over the years. I’m not really worried about getting burned my skins like redwing boot leather. Theres a cream thats like a peel mask that works ok and tube socks with finger holes over the arms help a lot to.
I may have him talked out of doing it this way we will see. Either way I wont be responsible for it if he does and it will be in writing.[/quote]

Well, if it helps any, I guess you could tell him that some nameless, faceless, roofing consultant on the internet said it was a bad idea, sight unseen. :mrgreen: Seriously though, I wouldn’t do it, but that is just me.


#14

borna roofer
i actually was born a roofer as i am 3rd generation.the two before me installed nothing but pitch. i personally have been installing ctp since 1967. and torching since the early 70’s. i have only patched pitch or tied off to pitch as it is NOT a good substrate to torch to.try water babies spf 50 it works well for pitch burn.


#15

Axiom and cerberus please turn your heads.

i have torched since 15 and ive torched to every
thing except the kitchen sink.

sweep your rock CLEAN,
and torch your roof on.
and yes the pitch will catch fire easily.

try a couple a sq . see if you can do it.

gweedo.


#16

[quote=“gweedo”]Axiom and cerberus please turn your heads.

i have torched since 15 and ive torched to every
thing except the kitchen sink.

sweep your rock CLEAN,
and torch your roof on.
and yes the pitch will catch fire easily.

try a couple a sq . see if you can do it.

gweedo.[/quote]

yer funny Gweedo, don’t ever go away. :stuck_out_tongue:


#17

If he accepts the proposal ill do it but I gave an alternate to do a fully adhered epdm thats not a whole lot more and ill give a warranty on it. Hopefully he makes the smart choice.


#18

Are you insane man a fa over pitch i have done it for another contractor 250 sqs man never again. But i did the smart tye-in with the metal and 6"p/s on one side and 5 course and pitch mastic on the other .There was still 140 sq he did not want to do.


#19

Im not going to glue to the ct im putting insulation down first.


#20

I knew you where not going to adhere to the pitch but you should be thinking of the ozz backing up through the screws. i put a sep sheet down then the iso.jmho