In our quest to honor Frank Lloyd Wright’s original specifications and intent, we’ve been focused on deconstructing and reconstructing the puzzle that are the milling profiles to build the parts and pieces. And we’re using the image below as our main guide. The more we study this drawing, the more we learn. In fact, the level of Wright’s brilliance and forethought contained on this one page seems stunning – out of this world – to us amateurs.

Here are a few of the things to notice:

• Angles are carefully engineered and featured, especially on profile numbers A-1 and A-2 on the exterior, which are multipurpose. A down-sloping ~60° angled baseboard carries rain over the tops of foundations walls. Around windows, the same ~60° angle is repeated, but in a mirror image: down-sloping on sills and upward on the headers. This does three things: sheds rain, lets light in (more light can get in from above the window) and opens sight lines (from the inside, the window opening appears much larger than it is. The occupant can see both gardens and sky.) However, as one Facebook friend posted recently, the header design was imperfect; creating a catchment for rain that would eventually leak. This issue was corrected on our house sometime in the 1930s with flashing. It is worth noting that the same angle appears on sills at Taliesin in Spring Green, Wisconsin, but not on the headers.
• The interior profile B-9 is particularly elegant in its design-for-manufacturing. First, only one profile is used on all sides of the box that makes the interior window frame and can be butt-jointed during assembly, so a box can be built quickly. By leaving a tab on one end when joining corners to mate with a slot on the mating part, the joint overlaps for a clean, crisp edge, as seen here:

• The same part number B-9 is also designed to mate perfectly with part number A-4, which makes up the exterior window frame. This complex, puzzle-like geometry creates a strong and watertight seal around the window. Indeed, the piecing together of many non-square parts in this section is breathtaking.
• You may also notice that B-9 has a milled groove where the sash butts. We believe (we’re working with other American System-Built Home owners to confirm) that this may have been designed to receive a section of waxed rope to act as a gasket when the windows were closed.

• Finally, we expect that strength was engineered into these window frames, in part, to take up the work of weight-bearing that might have come from a header in a conventional design. The complex joinery between part numbers A-2, A-4 and A-15 suggests that weight would be transferred from a substantial window box onto the center-points of in-wall studs. This, however, is conjecture. We don’t plan on taking down a wall to measure and prove our case.

What genius do you see in this drawing? As always, we appreciate expert opinion in the comments below:

About this blog: The Elizabeth Murphy House is a 103 year-old American System-Built Home and the protagonist in the book “Frank Lloyd Wright’s Forgotten House.”