On Fri, 02 Nov 2007 05:26:27 -0700, Larry Jaques
wrote:
On Thu, 01 Nov 2007 22:32:59 -0700, with neither quill nor qualm,
Bruce L. Bergman quickly quoth:
On Thu, 01 Nov 2007 16:57:12 GMT, Dan_Musicant
wrote:

I'm wondering how practical a metal roof would be for my garage, which
is WAY past due for a reroof. it's virtually completely flat, 20 x 30
feet. I think there's a slight rake because there's a gutter along one
30 foot side. Normally, a flat roof would mean hot tar, virtually
impossible DIY and probably only good for 7 years. I figure a metal roof
properly/adequately installed might last a LOT longer, possibly with
occasional upkeep of some kind. Can anyone on this?

I wouldn't go with metal on a practically dead-flat roof because of
the 'standing water going over the edges of the seams' problem. And
there has to be at least a little slope for drainage - that close to
flat, you'll have low spots that puddle, and rust will start...

So he could always frame up some tiny trusses and go with metal,
insulating the open space created after ventilating the roof properly.

You could false it out and put some slope there, and then have
enough slope to use a metal roof. Remember to add eave vents on the
ends and perhaps a bit of ridge vent at the center, so there is some
air circulation in the new "attic".

Torch-down Modified roll roofing on a properly prepared substrate
(felt and underlayment) would hold up fine - that's our back patio.

Tell me about torching-down MRR, please. Speaking of which, I just
swung by HF yesterday and picked up one of the self-igniting weed
torches. I've heard they're good for hot tar mods, too.

That's all it takes - you start to place the roofing from the bottom
of the roof and flip it over, heat the backing with the weed torch
till it melts, then flip it over and press down the edges with a heavy
floor roller.

Hope you got the torch with the pilot light valve and the trigger
main valve - much better control over the intensity. The piezo
lighter is of dubious value - IMHO something to break when dropped.

I need to redo
my back porch with a downward angle and reroof. The original installer
had it V-shaped (tilting back toward the house to drain into the
gutters) and it leaks into my back wall. sigh

Get a sheetmetal specialist to look at it - they do make special
metal for rain-gutter use, with an edge that you torch the Modified
Roofing on the patio roof down to. The other edge is tucked under the
drip edge metal from the house roof, and caulked.

That, or put a scupper drain at the low spot of the patio roof, and
take the Modified Roll up to and under the regular roof shingles.
Always more than one way to attack a problem like that.

I'll probably go with
MRR or maybe shingles. It's only 8x10ish. Then again, once I get it
stripped, I may want to move to metal or just peel more off and go
with fiberglass for the extra light in the dining room. We'll see.

Regular roofing with some simple "single-pane" skylights with curbs
is going to hold up better than fiberglass sheeting. When the
fiberglass goes bad you have to replace the whole roof again.

You may have to special order the "cheap skylights", because they
figure they're all being used into an inhabited space and have to be
double pane for the thermal insulation. If you are over an open
patio, there are no such restrictions - you might even want the ones
with the ventilation louvers on the top edge of the curbs.

-- Bruce --