Change in Window Configuration
|Click on the drawing|
Adding Height to the South Wall
|An end of the truss jig was cordoned off with|
2 x 4s for making 24" x 15" inserts; the plywood,
nailed to a 2 x 4 frame, serves as a gusset
I temporarily modified the jig that I used for wall trusses to make 24" high inserts to go between the window sections and the floor. Admittedly, the inserts looked a little goofy but, when tied in with bolts, nails and strapping, they did the job.
Raising the Wall
|The four wall sections before raising; the section with the saw|
laying on it and without its top and bottom plates is to be
raised last (click on the photos to enlarge them for more detail)
|Unsuccessful attempt at using wall jacks|
Step-son, Keith, helped raise the walls. We assumed that the sections would be too heavy for raising without wall jacks but, after we were half through with using them for the first unit, we realized that they were not properly adjusted for a 10' wall and had to lower the wall back to the floor. Instead of adjusting the jacks, we removed them, under the assumption that we had under-estimated our ability to raise the wall without them. So, in order to keep the wall from sliding over the edge of the floor, we used rope to tie the bottom and the top of the wall to the existing wall to the north. Then two of us raised the first unit surprisingly effortlessly and continued to do so for the other three units.
As soon as the first three units were upright and the bottom plates were temporarily fastened to the floor with duplex nails and the top plates fastened together with clamps, we could dry-fit the unattached 2 x 6 plates for the last unit then attach them to the unit. When we raised the unit, it fit nicely between the two adjacent units.
Aligning and Securing the Wall
As the units were raised they were stabilized with braces between the wall and the floor.
|Second story wall housing a total of twelve 3' x 5' windows|
|The wall from a different perspective; notice the nailers over|
the window openings for safety reasons; the height is just
over ten feet; the window sills are slightly too high to meet
code for egress
We started the alignment by straightening the bottom and the top using taut mason's lines while loosening and refastening the tops of the braces and the duplex nails as needed. The clamps sufficed for the top temporarily. As with conventional 2 x 4 or 2 x 6 walls, we used a double top plate, i.e., a second layer of 2 x 6's stacked on top of the ones that were nailed to the wall sections before raising the wall. We installed the ones on the interior side of the wall first and used them to pull the wall perfectly straight and hold it straight, assisted by a mason's line. Of course, as is standard practice, we staggered the locations of the ends of the boards relative to the first tier of top plates so as to stiffen the wall.
The floor under the wall was not perfectly level so the top of the wall also was not perfectly level, primarily in one area. In order to correct the problem, we used shims under the bottom plates to level to a mason's line the top of the wall.
All that remained now for proper alignment was to plumb the wall in a north-south direction and secure it definitively to the floor. For plumbing, we used shims under the bottom plates as necessary while loosening and reattaching the braces. Then we used 6" construction screws and nails to fasten the bottom of the wall to the floor joists and band-joists.
Our location places us at risk for two catastrophes. Two hundred feet below us is an abandoned coal mine and subsidence is not uncommon in ours and the surrounding counties. Also the New Madrid fault in southeast Missouri near its border with Tennessee has a 25 - 40% chance of a magnitude 6 earthquake within 50 years and a 7 - 10% chance of a 7.7 magnitude. Either would cause serious damage in the St Louis region. Consequently, the final job to secure the wall was heavy hurricane strapping to tie it to the lower floor framing and to the major beam under the catwalk.
The purpose of cripple studs under the window openings is mostly for fastening sheathing
|Cripples anchored at the bottom by 2 x 4s|
I spent a few minutes making a temporary jig in which to nail the double cripples to a short 2 x 4s before nailing them in place. I opted for the 2 x 4s cross-ways of the bottom plates rather than toenailing the cripples directly to the plates to make the cripples easier
|Quickey jig for nailing cripples to 2 x 4s|
All exterior walls for the house are designed for trusses 24"oc due to their stiffness. The cripples, however, are 16"oc just like the typical 2 x 4 wall framing of most houses.