Residential Architects and Engineers....roofers

[Bronco]

That's what we are proposing 1/4" per foot. I say 3:12, because @ 1/4 per foot it rises 3" in 12'. But, after talking to people, 3:12 may mean 3" per foot. I leave this stuff to the architect, but I am deficient on the lingo.

it's a 3:144

[::: :::]

Iceman, regarding the flat roofs v. pitch, keep in mind that Promontory has a height restriction of 28' from grade, and below grade bedrooms is not acceptable to me. I hate looking out of a window and seeing a rock

in many jurisdictions, gable roofs are measured to the halfway point of the roof ridge...not sure what you've got there in the zoning regs

after talking to people, 3:12 may mean 3" per foot. I leave this stuff to the architect, but I am deficient on the lingo.

yeah, that's the industry standard notation for a traditional sloped roof -- rise:run [in inches]
anything below 3:12 is a low slope roof

[shafty85]

Nice looking place. I haven’t followed too closely, so this may have already been covered, but do you have a budget you intend to stay within? Assuming you do, have you shown any plans to a/your contractor and discussed the type of interior finishes you want so as to confirm that you can afford what the architect is designing?


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[schindlerpiste]

Yes, I have a budget. I have met with 3 builders who are familiar with the plans, my budget, all my finishes and want the job. It will go out to all three for bid after Promontory approves and the engineering is done.

[adrenalated]

Where are the chambers for the servants? Outbuilding?

[RootSkier]

Yes, I have a budget. I have met with 3 builders who are familiar with the plans, my budget, all my finishes and want the job. It will go out to all three for bid after Promontory approves and the engineering is done.

Please pick the cheapest one and keep us informed about how that works out.

[Slopetime]

Wonder how the window seals will perform over months and months with snow packed against them, at those cleristory units. The flashing on those wall to roof connections is the most crucial detail on that residence.

[mcski]

Where will the gimp sleep

[Djongo Unchained]

Hold the fuck up.

1/4" drop per foot of run? That's so close to flat, there's no way that will all run off. Puddling unless flawlessly flat.

Tell me I read that wrong.

Paging SFB - hey you ever roof a 3/144 pitch?

[savemeasammy]

1/4” per foot is good for plumbing drain/waste lines, but not so much for a roof in snow country.

[iceman]

Hold the fuck up.

1/4" drop per foot of run? That's so close to flat, there's no way that will all run off. Puddling unless flawlessly flat.

Tell me I read that wrong.

Paging SFB - hey you ever roof a 3/144 pitch?

You read it right but it'll drain if it's flat/smooth, water needs a lot less slope that that to flow. About an eighth of an inch per mile and water will move.

[::: :::]

At 1/8 per foot slope, capillary action can prevent water beads from moving downhill. Mass water is different; it will relentlessly act at gravity’s direction. (Surface roughness is a variable in all this that adjusts the degree, as is wind or phase of water [ice, snow])

So, 1/4” per ft (double the 1/8” slope) is considered the minimum for “flat” roofs.

[Slopetime]

Yeah, I'd try to get a min. of a 1/2:12 if I were going to do a flat roof anywhere, but 1/4" is pretty typical for a flat roof application.

[RootSkier]

Hold the fuck up.

1/4" drop per foot of run? That's so close to flat, there's no way that will all run off. Puddling unless flawlessly flat.

Tell me I read that wrong.

Paging SFB - hey you ever roof a 3/144 pitch?

Let's let nature run its course here, man.

[Djongo Unchained]

I'm getting the physics here but my first hand experience tells me - No.
Just one FOG opinion.

Maybe the key variable is - Snow country. piles of snow in shady corners melting slowly.

Op should make his roofer the critical hire.

Yes, rootskier, yer right. Just gonna let it flow. or leak.

[schindlerpiste]

Right now, the plan is for corrugated corten steel with the entire roofs lined with Bitchuthene (Bituthene) membrane and the 4' overhangs possibly lined with electric radiant heat, rather than heat tape.
This should eliminate leakage

[m2711c]

Elevated leakages, huh? Sweet.

[schindlerpiste]

Whoops!

[lifelinksplit]

I just got done putting a 3/8in per 12in roof on the new fire station in Bozeman(framed not roofed). So I guess you're in good company however they have the advantage of taxpayers fixing any fuckups haha.

[Art Shirk]

I just got done putting a 3/8in per 12in roof on the new fire station in Bozeman(framed not roofed). So I guess you're in good company however they have the advantage of taxpayers fixing any fuckups haha.

Did you also do the drywall at the new McDonald's in Las Colinas?

[Djongo Unchained]

Right now, the plan is for corrugated corten steel with the entire roofs lined with Bitchuthene (Bituthene) membrane and the 4' overhangs possibly lined with electric radiant heat, rather than heat tape.
This should eliminate leakage

Hire a master at installing that underlayment. There are many quality types of it, research the best for your weather zone.

Hermetically seal that bitch.

[Foggy_Goggles]

Bitch/Grace/Vycor/Ice and Water Shield isn't designed for flat roofs/standing water really. I'm saying that from the perspective of seeing what works over 23years at 8K+ ft.

Seriously, ask around. EPDM mechanically fastened by a specialty contractor is what works. Corten = rusty metal? That doesn't really tell me the gauge and profile.

Honestly, your flat roof design really is leading to some combination of money and or problems. The more money you spend, hopefully less problems. Think "swimming pool". Ask yourself, would plywood + a peel and stick membrane + a metal roof assembly with seams and screws that go through all of it hold water indefinitely?

Ask around and see what works on the commercial buildings with flat roofs in Park City? What type of warranty can you get with this design (from your roofer, not your BS home builder one).

You are a long standing member of this community and by all accounts a stand up dude. I'm really trying to make you aware of the possible headaches here. I'd love to be wrong but this project screams "fucked from the start". Just remember, nobody has your back. Everybody is looking out for themselves.

[::: :::]

I’m trying to not criticize what I’ve read here and just take it with a bit of perspective that OP doesn’t fully understand the lingo & process (and neither do we watching from the internet).

It may be fine or it may not be.

I’d suggest OP really spend some time grilling his design team on the roof system so that he understands what’s proposed and how it works in the conditions they’ll encounter at that site.

“bituthene” can represent a number of waterproofing product types including flat roof systems. Understand what’s proposed there. I would still want to know a lot more about how the metal system is attached to the roofing system because of the implied penetrations required.

[Foggy_Goggles]

AC = khakis and golf shirt professional answer

Foggy = dirty Carhartt's more tact needed answer

[Slopetime]

AC = khakis and golf shirt professional answer

Foggy = dirty Carhartt's more tact needed answer

I'd rather have the Carthartt, from the trenches answer, tact means shit when the roof is leaking over your baby seal hide covered floors.

Flat roof systems are problematic from the start, and down the road. Unless you're foaming the cavity solid (big dollars), heat gain is an issue, so venting becomes another detail to consider. Venting flat roofs is another potential leak location.

In a snow or high rain zone I'd be designing with a min. 3:12 metal roof and would prefer 4:12.