Modified Torch Down

Mark

I am planning an 888 sq ft addition to the store to start next month. I currently have modified bit on the other part with a 2/12 pitch shed style roof. I am going to manage the project myself and do a good portion of the finish but roofing is not something I am going to do. How do you usually charge for this... by the sq ft ? What should I do to prep for mod bit as in substrate and how many layers or thickness is common. We get lots of snow up here and cold temps at times.

Mark

__________________
Mark

www.benmoorestore.com

Grumpy

Charge by the square. square=100 square ft.

Snow=cold. Consider a layer of ISO insulation ontop of the substrate.

felt base underlayment 33# or 43# We like to install a double layer mechanically fastened (screws) over the insulation.

Modified bitumen torch applied to the felt is the best method IMO. You need an experienced roofer to do this. If you can't find one try the glue down (SBS-Modified Bitumen). This is much safer.

One layer is obviously minimum and to be honest we've left many roofs with one layer. If you do only one layer have it silver coated after it has a chance to age for a year. This protects against UV rays. If you do a second layer make sure it's a granulated layer. BTW if we do one layer we always try to make that a smooth layer. It takes an experienced roofer to imbed the granuals for proper adhesion.

A roof is only as good as it's flashings so we prefer to use metal flashings, instead of field fabrication of the rubber.

dougger222

My father has been doing the torch down method for years now. We together have done 5 or 6 in the last few years. Here's what we do. First we apply ice and water shield, then base sheet, then we torch down the roll roofing. The other day I bid a roof that had four squares of flat roofing that actually had two layers of asphalt shingles in it. If I get the bid it will have torch down flat roofing.

Grumpy

Interesting... Ice shield on a flat roof? I never thought about that.

Glasshousebltr

Mark, to me torch down is a simple process, just don't burn your place down. :-)

I think the toughest part is keeping the run straight. It takes 2 sometimes 3 people. Naturally 3 being better.

To keep it straight, roll it out and cut it to fit. Pull half of it back to center and lay it over the untorched half. As one man torches the underside (to small visable bubbles) The other two push the half slowly back into place useing the untorched beneath as a guide.

If you don't keep it straight it looks like crap.

On seams be sure to heat both sides.

It's best to go over blackboard with screws and caps like grump said.

I don't put felt under the blackboard, but it sounds like a good idea.

Have fun......it's really not that tough. The first time I did it I studied then just did it, turned out nice.

Bob

jmorgan

You guys would be surprised how much of our Grace Ice & Water Shield is under various flat roof systems. As a vapor barrier under insulation topped w/single ply is very common. Also very common as temporary roof after tearoff and before new roofing is applied. Allows better seperation between tear-off crews and roofing crews. Tearoff crew installs the IWS.
Jim

Teetorbilt

I started a new thread asking about Grace products. I neglected to mention that I have a flat roof over the florida room. This product will seal a flat roof?

Grumpy

Teetor using grace on a flat roof is new to me. I see no harm in it really, however it may be over kill.

If your planning on doing this florida room yourself I recommend a peel and stick system. Spend a few extra bucks to get the mid ply so you have a 3 ply system.