The roof over Kentuck Knob

To control SPAM, you must now be a registered user to post to this Message Board.

EFFECTIVE 14 Nov. 2012 PRIVATE MESSAGING HAS BEEN RE-ENABLED. IF YOU RECEIVE A SUSPICIOUS DO NOT CLICK ON ANY LINKS AND PLEASE REPORT TO THE ADMINISTRATOR FOR FURTHER INVESTIGATION.

This is the Frank Lloyd Wright Building Conservancy's Message Board. Wright enthusiasts can post questions and comments, and other people visiting the site can respond.

You agree not to post any abusive, obscene, vulgar, slanderous, hateful, threatening, *-oriented or any other material that may violate any applicable laws. Doing so may lead to you being immediately and permanently banned (and your service provider being informed). The IP address of all posts is recorded to aid in enforcing these conditions. You agree that the webmaster, administrator and moderators of this forum have the right to remove, edit, move or close any topic at any time they see fit.
SDR
Posts: 20438
Joined: Sat Jun 17, 2006 11:33 pm
Location: San Francisco

Post by SDR »

So, if the work we see at Hagan is relatively recent, there is hope of learning from the people who did it ?


SDR

DRN
Posts: 4081
Joined: Mon Jul 10, 2006 10:02 am
Location: Cherry Hill, NJ

Post by DRN »

Laurie Virr wrote:
DRN:

Do you still have the details of the roofs you designed?
I don't; the drawings stayed with the firm I with at the time of the design. I used the ATAS standard details for their proprietary panels, but with the warning from the manufacturer that the panels were most commonly used in southern states, and that they would be vulnerable to leaking if ice dams occured, I treated the metal roofing as an outer shell for a membrane roof beneath. I set the Bermuda roof on a system purlins or sleepers that would allow any water that might get under the panels to drain down across the protective membrane below. In essence, I treated the Bermuda roof like a rain screen before the term became part of the architectural lexicon. Ideally, the rolled seams used in traditional Bermuda installations such as Kentuck Knob or Dobkins would have been water tight in and of themselves, but the budgets with which I worked at the time would not allow that level labor, so I made do with what was available commercially.

It was noted that the ATAS system used metal caps at the hips...that was the standard and preferred detail by the manufacturer, but there was an alternate detail that would allow the "stepped hip" more commonly associated with Bermuda roofs, which is what I used. The panels on either side of the hip line met but were held apart a fraction of an inch at the hip joint. Beneath the joint, what could best be described as an inverted 'V' section step flashing was inserted to allow water that got between the panels to drain down. I don't recall exactly how the panels locked into the step flashing, but as I remember there was a means to prevent water from traveling horizontally away from the hip.

SDR
Posts: 20438
Joined: Sat Jun 17, 2006 11:33 pm
Location: San Francisco

Post by SDR »

I just came across a giant PDF which seems to contain virtually everything one might want to know about Kentuck Knob. Billions of images, many purpose-made or borrowed from obscure sources. Palli Davis Holubar, note section on "Wooden Cutouts" near the end . . .

http://www.andrew.cmu.edu/user/gutschow ... eboll1.pdf

Happy scrolling ! SDR

SDR
Posts: 20438
Joined: Sat Jun 17, 2006 11:33 pm
Location: San Francisco

Post by SDR »

David C sends along cuts from pp 24 and 25 of the March 1958 "House and Home" magazine. These may come too late to be of use to Laurie Virr or others, but is still of interest. Love seeing the nitty-gritty, from the horse's mouth, as it were . . .

Image

Image

Image

Tom
Posts: 3235
Joined: Sun Jan 30, 2011 7:53 pm
Location: Black Mountain, NC

Post by Tom »

That Carnegie Mellon link has some good info. Thanks for posting.

Tom
Posts: 3235
Joined: Sun Jan 30, 2011 7:53 pm
Location: Black Mountain, NC

Post by Tom »

dfja;fjkle ;rje lkJ IJVFCl;ck eor kdmc a,fnwlkdfn
Last edited by Tom on Wed Jun 09, 2021 1:14 pm, edited 3 times in total.

Roderick Grant
Posts: 10688
Joined: Wed Mar 29, 2006 7:48 am

Post by Roderick Grant »

In Bernardine Hagan's book on the house, page 12, there is a cross-section of the living room showing a slight difference between the pitch of the exterior roof (22.5 degrees) and interior ceiling (17 degrees), with a scissor truss of 5.5 degrees, which doesn't seem very convincing from a structural point of view. However, the eave ends of the system suggest a substantial horizontal truss comprised of roof, soffit and extension of the exterior walls through the soffit to the roof. The drawing is not too clear, but it looks like it's all wood; I don't see any steel elements in that particular drawing (done by Stewart Township, not Taliesin).

Tom
Posts: 3235
Joined: Sun Jan 30, 2011 7:53 pm
Location: Black Mountain, NC

Post by Tom »

Roderick is right about the structural triangulation in the framing. The as built drawings from the Carnegie Mellon PDF show this nicely.
The Carnegie Mellon PDF also shows steel in there especially over the full height french doors of the living room. There is a large steel channel in the section but there is also a smaller steel box beam laid on it's side over the top of the doors with 1-3/4 in steel angles extending from it. I don't really understand this yet

Correction to my post immediately above where I describe the apex of the hip roof. There are not two smaller rafters that frame into the western end of the larger steel flitch beam over the living room, there are three. Still there is a lot of steel and bolts where those members come together.

...Of those three smaller rafters that form the hip, the southern most one bears directly over a full length mitered glass detail! So one has to wonder how is he dispersing the weight here? It's a very heavy roof of wood, steel and copper.

Tom
Posts: 3235
Joined: Sun Jan 30, 2011 7:53 pm
Location: Black Mountain, NC

Post by Tom »

Just back from looking more closely at the as built drawings. They've drawn two sections at 1/2" scale: transverse (A13) and longitudinally (A14) through the living room. The southern and western edges are wrapped by a steel channel sandwiched between 2x12's. The rafters of the hip bear upon those which in turn rest on stone piers.

B7 has some very interesting details but the notes are not legible.

Tom
Posts: 3235
Joined: Sun Jan 30, 2011 7:53 pm
Location: Black Mountain, NC

Post by Tom »

The transverse cross section of the living room (A13 and first page of the PDF after Cover page) gives good detail of the ridge. It may be that the ceiling angle and roof pitch are different in order to open up the ridge space and conceal a collar tie.

Has anybody a clue what the "steel box beam" (tube steel section) is all about? Some form of lintel I guess.

Tom
Posts: 3235
Joined: Sun Jan 30, 2011 7:53 pm
Location: Black Mountain, NC

Post by Tom »

Amazon lists the Bernadine Hagan book new for $300, used at $165. OUCH!
Roderick, what did you get it for?

SDR
Posts: 20438
Joined: Sat Jun 17, 2006 11:33 pm
Location: San Francisco

Post by SDR »

Hmm. Well, it looks like a treat -- even if the publisher is illiterate ("pre-occupied as Wright was with large institutional projects . . ."). My recent book-splurge can't really extend itself this far, unfortunately, so I'll have to wait for the paperback (?) . . .

Wait -- when was this book published ?

SDR

Roderick Grant
Posts: 10688
Joined: Wed Mar 29, 2006 7:48 am

Post by Roderick Grant »

Bernardine Hagan's 220-page book "Kentuck Knob" was published by:
The Local History Co.
112 N. Woodland Rd.
Pittsburgh, PA 15232
... in 2005. There is no price listed on the book. I got my copy free; Don Hoffmann sent me his copy, given to him by Mrs. Hagan.

The book is about the whole experience from Mrs. Hagan's point of view. It's not all that informative on technical matters, though there are some interesting photos taken during construction, plus a preliminary plan (pg 9) by Davy Davison, which FLW rejected emphatically (according to Geiger) and an as-built roof plan (pg 11) showing a slight error by FLW in aligning the two major roofs, leaving a flat place next to the kitchen mass that rises above the roof. Typically, FLW flew into a rage over this flaw, and blamed others for not catching it.

Duncan
Posts: 102
Joined: Sat Apr 21, 2012 11:05 pm

Post by Duncan »

Printed on the dust jacket to my copy is $39.95

Paul Ringstrom
Posts: 4467
Joined: Sat Sep 17, 2005 4:53 pm
Location: Mason City, IA

Post by Paul Ringstrom »

Kentuck Knob offers another side of Frank Lloyd Wright

http://triblive.com/aande/architecture/ ... ntuck-knob
Owner of the G. Curtis Yelland House (1910), by Wm. Drummond

Post Reply