custom roof help needed

[Anonymous]

Hi can any help me build a custom roof , i need to create a sloping floor for a theatre and cant for the life of me work it out , any help greatly appreciated.

[Anonymous]

Hello Gerald,
Thanks for your reply.
If it is not a trouble, I would like to know
how the crew did this. Thank you.
Peter Devlin.
P.S. What happened to rumplestilskin in a tub ?

[Anonymous]

Peter wrote:
In your image you call out a sloped SOG.
I wonder how steep a slope is practical
for concrete work. I have not sloped form work
more than maybe five degrees and wonder
how steep the form work can be before the concrete
just keeps slumping and cannot be held in place
until it kicks off.

I'm not sure of the limits to sloping concrete. In the theater we aren't going much over 1 in 12. We're actually topping over an existing sloping slab. The project is in schematic design phase so I'm not too concerned about means and methods.

I used to work with Terra Dome who place monolithic concrete over a curved fiberglass custom form. Depending on the structural requirements I imagine that you can adjust the slump and maybe add accelerants to minimize flow.

You might want to check with engineers, contractors, concrete manufacturers and testing agencies for more reliable advice.

[Anonymous]

Hello Matthew,
Thanks for posting back.
I know a man at the American Concrete Institute.
I think I will give him a call. Thanks for the suggestion.
Peter Devlin

[Anonymous]

I talked to a man at the Portland Cement Institute
about how sloped concrete is done and he told me
the following. Basically, it is the water content of
the mix. At significant slopes the the mix must be very
dry (2" slump or less) making the concrete quite stiff .
If the concrete is four or five thousand psi it does not
have to be consolidated though it is not as strong as
if it were consolidated. He told me that slopes of
75° or more can achieved.
Thank you,
Peter Devlin

[Anonymous]

I used to work construction on water diversion projects. We poured concrete at 70-80 degrees (90 being vertical). You just need a lot of reinforcing to hold the mud and a very dry mix.

Think swimming pools.

[Gerald Hoffman]

Peter,

I finally got in touch with the concrete fellow that did the roof section that I was talking about. He said he used a slightly dryer mix but also was able to cover the top over with 2X6's and worked up the slope closing the concrete in as he poured uphill. In this case the upper surface of the concrete would not be exposed so it didn't matter if it didn't look perfect.

Cheers,

[Anonymous]

Hello Gerald,
Thanks for the research and posting back.
As you can see I did some research myself
and posted some information about this issue.
Thanks,
Peter Devlin