Flat Roofs

[abqjimlynch]

and no sharing>

[dhowardaia]

Maybe I'm missing something, but didn't he say the roof pitched 6''? That's not flat...

Dorothy

[Curtis Johnson]

To All:

I stand corrected on the "0" pitch roof subject ... thank you Scott and Louis for making that clear. I don't do flat or nearly flat roofs in my market area although I have made custom ceiling planes at "0" pitch many times. Technically I guess I knew the right answer but didn't put enough thought into my answer. I hope I didn't create too much confusion in this matter.

Sal:

Did you get your roof, parapet walls and skylights (and framing) to build OK? I have seen (Professional Roofing magazine articles) for commercial buildings where they used tapered foam insulation panels for drainage over the roof framing structure and then place the finished materials (membranes, etc.) over those for a finished roof system. I was just curious what you were going to do to establish your shallow pitch.

I am asking this because I just met with a customer yesterday who is considering doing some "flat" roofs for a Southwest/Tuscan type design and I may need to get up to speed on how to best do them including structure, membranes, sealing, drainage, ideal pitch, etc.

[geno742]

I recently designed a 1/4" :12" sloped roof. The method I used, and it has been built so the county approved of this method, is pretty simple.
Use rafters with "0" pitch and size them accordingly to span. Take a 2 x and rip it to the proper height and cut it diagonally.
An example will make this clearer. If the width of the building is 20' then the pitch @ 1/4" is 2 1/2" rise @ 10' length. Rip a 2 x 4 x 10' to 2 1/2" wide. Cut the 2 1/2" x 10' diagonally. Take each of these triangle shaped pieces and nail them directly on top of the rafters. You now have a 1/4" slope to nail the roof sheathing to and apply your preferred roofing materials. The framer smiled when he saw this method.

[abqjimlynch]

Here in Albuquerqe (lot's of flat roofs)we actually call those ripped pieces "rippers"

[geno742]

Yeah, that make sense. "Rippers". It is a great way to accomplish low slopes for sure.
Makes a weird detail in Chief for me at least. Lots of verbiage to make the drawing clear.
Framer scratching his head "Huh?"