Torch Type Roof: Can You Torch A New Roof Over That Or Do You Have To Rip The Old One

Handyman

torch type roof: can you torch a new roof over that or do you have to rip the old one out. A friend of mine has a Flat style roof on a building with about 4 apartments in it. It's leaking towards the front of it where there is a large slope to accomodate the front of the building being higher then the actual roof. I guess it was a type of design. Well. the apartment below gets leaks. The roof is really old. There's alot of crevices and crack type lines in the roof.

Can I put a coat of rubberized coating over it or should I just install a new roof. Can I lay a new torched roof over that or must I rip the old out?

Can someone help me?

Grumpy

The answer depends upon what you currently have. Is the existing roof modified bitumen? If yes, is the existing roof smooth or granulated modified?

If the roof has cracks, coating it will be a waste of money IMO. There are some speciallized coatings but they take special equipment and knowledge of how to use that equipment (kold king).

Ripping the old roof off is always preferred, especially when the old roof has leakage.

Grumpy

Oh yeah one more thing I don't recommend the use of open flame by a person who is unskilled in the proper use of the torch, unless supervised by someone who is skilled in torch.

Teetorbilt

Grumpy, I have a nearly flat roof over my florida room. It leaked just a little (>quart) where it joined the house. Not bad for winds that approached almost 160 MPH. It is hot torched but old. I am thinking of installing Grace and running it up under the fascia of the roof.
Opinions?

Grumpy

Sounds like a good idea as far as running the material under the fascia. That joint is the point most florida rooms leak (around here anyways).

The problem is, I don't think that grace and modified are compatible.

Would it be possible for you to draw and post a profile of how the florida room meets your main house?

I could then modify your drawing with my waterproofing idea.

927-ROOf

If it's an asphalt roof with no gravel then you can put your modified roof over it, that is if the extra weight is not an issue. If those cracks you're talking about are due to movement then I'd reconsider. If the roof is something else then you'll need to mechanically install a barrier and base sheet before applying a tourch down. If you don't know much about the tourch down system then you really could be playing with fire!

Specialist

If you do not have experience, stay away from it. I have installed many torch down roofs, but we do not allow any open flames on our roofs here. By the time you notice the interior leaks, the roof has been leaking for some time. It is ALWAYS preferrable to tear the roof off to inspect the deck. How do you know the last guy did it right? Is the insulation adequate? Is it wet? If it is wet, then it is worthless as insulation. If the roof is old and needing replacement, you can't go wrong with whatever "crap" you want to slap on it just to keep out Mother Nature. Just realize that this is a short term fix.
-bill

Teetorbilt

Grumpy, I'd tear off everything and resheath if required. It's only about 24 X 16. I'll see about a drawing, sometimes I can make it work and sometimes not.

927-ROOf

Looks like everyone told you the truth on this one. Now you need to ask yourself do you want to do it right, safe , or cross your fingers and hope you can getterrr done without burning everyone out of house and home. Then again here may be a chance for you to find someone that knows their stuff and get them on the roof with you! Everyone had to use a tourch for the first time, and had to go over an exsiting roof for the first time. Although I too think a tear off would be best, I know what it's like to work for those that only want to invest just enough money to hold them a while. These types often trip over a dollar to pick up a dime.

Grumpy

lol getterrr done. hehe