The roof over Kentuck Knob

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Tom
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Re: The roof over Kentuck Knob

Post by Tom »

The CMU pdf says that Key (might be contractor I don’t know) thought the roof structure was insufficient for winds loads and added steel, continuing with the usual line that Wright got all angry.
But I don’t see how that could be an accurate story given that the framing plan shows a super strong roof, one that according to the CMU-pdf was actually steel reduced before building.
I don’t have it open now but I’m assuming Wright approved that framing plan. It may even be signed by him.

Tom
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Re: The roof over Kentuck Knob

Post by Tom »

We’ll, looks like his initialed signature is in the red square.

SDR
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Re: The roof over Kentuck Knob

Post by SDR »

Tile or slate would be heavier than asphalt roofing; would copper be lighter than asphalt ?

S

Roderick Grant
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Re: The roof over Kentuck Knob

Post by Roderick Grant »

yes

Tom
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Re: The roof over Kentuck Knob

Post by Tom »

I think before SDR asked the question I would have thought it obvious that copper was heavier. You know it’s a metal and metals are heavy etc … I’ll find out how much the difference is and post here.

The CMU/PDF (this is all probably from Bernadines book) says the Hagans suggested a split shake roof, but this spelled f i r e to Wright. PDF says Wright called copper “the eternal metal” and he called his favorite type of copper, copper verde, the kind that turns green, “more eternal” He did have a sense of humor.

SDR
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Re: The roof over Kentuck Knob

Post by SDR »

Remember that the thickness of the various materials has a major effect on weight per sq ft !

S

Roderick Grant
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Re: The roof over Kentuck Knob

Post by Roderick Grant »

Refer to the drawings posted on page 3 of this thread. The copper was a very thin layer over plywood roofing. I suppose the weight of asphalt would be close to the thin copper, but I suspect somewhat heavier.

Tom
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Re: The roof over Kentuck Knob

Post by Tom »

20oz. CR Copper sheets 30” x 96”

I’m not familiar with specifying copper.
I thought the sheet would have been called out in its gauge.
Instead it is given in oz.
Does this mean the whole sheet is 20 oz. ?

Tom
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Re: The roof over Kentuck Knob

Post by Tom »


SDR
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Re: The roof over Kentuck Knob

Post by SDR »


Tom
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Re: The roof over Kentuck Knob

Post by Tom »

Sorry - meant to follow up that post immediately but had to stop.
To answer your question the comparison fails at the prow where I was initially looking, yet it's still kind of interesting.
First, I think it's clear that the main room of the original Usonians were modeled on Robie. At least that's what I think.
Kentuck Knob, although not one of the first, is no exception.
One of the elements of that Robie room is the levitating prow end. Kentuck Knob is doing the same thing and I thought at first that the framing might be similar.
That is I thought that the masonry pier at Kentuck's prow might be carrying a steel cross beam that helps support the roof as at Robie. Something like that is going on but it's not as clean.

Maroon: 12" steel channel
Blue: Vertical steel mullions
Yellow: Line of perimeter steel lintel.

https://www.flickr.com/photos/54449844@ ... ateposted/

https://www.flickr.com/photos/54449844@ ... ateposted/

Tom
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Re: The roof over Kentuck Knob

Post by Tom »

This is Berger, but I thought something like this might have been going on with Kentuck Knob - yellow hatch

https://www.flickr.com/photos/54449844@ ... ateposted/

SDR
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Re: The roof over Kentuck Knob

Post by SDR »

So, what do you suppose that second piece of steel, parallel to the first, is doing at Berger ?

S

Tom
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Re: The roof over Kentuck Knob

Post by Tom »

I don't know. My guess is that the longer one is not enough for that corner.
The second shorter piece of steel cantilevers over mitered glass.

Here's a shot of that corner which I took years ago, but it doesn't tell much.

https://www.flickr.com/photos/54449844@ ... ateposted/

Tom
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Re: The roof over Kentuck Knob

Post by Tom »

Looks like Berger might have been built without steel in any vertical mullions.

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