| Pg
3 | |||
| Framing
| |||
|
Framing exterior walls is a pretty straight-forward process. Assembling walls
on a level surface—probably the subfloor or slab—and raising them into
place will help you frame faster. However, raising walls usually requires some
extra help.
Standard walls are 8' to 12' high. 2x6s are now commonplace in residential construction
because they provide a wider cavity that accommodates more insulation than 2x4s.
But, the 2x4 is still most popular for remodeling and add-ons. Framing consists of top and bottom plates, wall studs, and headers, trimmers/kings studs as needed for window and door openings. Building exterior walls consists of these areas: For definitions used throughout this section see Framing Glossary
Marking Top & Bottom Plates
Wall studs can be purchased at even lengths (8', 10', 12') or purchased pre-cut. Pre-cut "dead-on" studs are cut at 92 5/8" and tailor-made for 8' walls when used with 1" drywall and 1/8" flooring. Your finishing materials may be different thicknesses, but here's how it works:
Assembling Walls & Corner Posts
Lay out the bottom and top plates on edge. Between the plates, insert the wall studs on their marks and nail the end studs in place. Once the wall is square, nail on the remaining wall studs.
After
the wall studs are in place, scab on one corner post for each corner joint. The
posts are necessary because butting two wall sections together forms a corner
joint with only one interior nailing surface. The corner post provides another
interior nailing surface for drywall. You can scab a corner stud a few different ways. There are other variations (like using drywall clips), but here are two common methods:
Once the corner post is secure, insulate the cavity before installing the sheathing. Once the sheathing is on and the wall goes up, the end of one wall section will cover the corner of the other.
Laying Out Window/Door Openings
On
the top and bottom plates, mark the center of the window/door rough opening. An
architect's plan will indicate where they go in relation to the corners, but double-check
to make sure the openings are in the right places.
Divide the opening widths in half and measure each direction from the center.
These marks indicate where the inside edge of the trimmer studs go. Cut the trimmers the height of the wall studs minus the header height. Then scab on the full height king studs to the outside of the trimmers and install them together. They're easier to handle this way and you can plumb them in place in one step.
Fit cripple studs on 16" centers above the header. In some cases, the header may
end up too close to the top plate to use cripple studs. So, that space must be
filled with lumber of that thickness. For windows, a sill plate at the bottom of the opening is toenailed into the trimmers and supported by cripple studs on 16" centers.
It's always easier to nail on sheathing before raising the walls. The added weight
on the wall is sometimes too much for two people to handle. So, get extra help
in raising the wall. It beats trying to nail up 4x8 sheets on a ladder. Line up the sheets to run down the middle of the studs; so the next sheet has a nailing surface. When you lay out the sheets, utilize the straight factory edges of the sheets. Eliminate slight bows in the wall studs by pushing them to run evenly with the edge, then nail the sheathing in place.
With the wall still laying flat, position the bottom plate on a previously made
chalkline mark (its width from the edge). Tack the bottom plate by toenailing
a few nails through the top of the bottom plate to the subfloor. Slowly walk the wall upright. The tack nails will help hold the wall in place. Tap the wall flush and square it into place with a sledgehammer. Nail the bottom plate to the subfloor -- into the floor joists if possible.
Overlapping the corner joints, nail the remaining cap plate sections on the top
plates. You may be able to take some slight bows out of the top plates, but they'll
need bracing.
Run a stringline to check how straight the top plate is. Straighten any top plate
bowing by pushing a brace board into the plate until it's flush. Anchor the brace
by nailing it to a stake driven into the ground. Place 2x4s diagonally from the top corners to the rim joist, a long brace on one side and a short brace on the other. However, this is just a guideline. You may need even more bracing for your project. | |||
|
| |||
| For
More How-To Information: | |||
Wall
studs are generally spaced 16" on center (O.C.). Set the bottom
(sole) plate and top plate flat. The first stud will sit on the
end of the plate. Measure and mark 15-1/4" from the end for
the near edge of the second stud. From this mark make marks every
16" for the near edges of the remaining studs. (The reduced
spacing between the first and second studs ensures that a 4-foot-wide
piece of sheathing can be flush with the outside edge of the first
stud but land in the center of the fourth stud.)
Most
plans call for two top plate layers. Fit the second cap plate on the top plate,
but cut it short to leave the ends exposed. After the walls are set, we'll overlap
the corner joints. 
Inspect the straightness of your wall studs before cutting them. Try to skip over
ones with bad warps or twists, because they're hard to nail flush and can throw
the stud spacing off. Keep them in mind for trimmers or cripple studs. 
We usually assemble the wall on the floor, nail it together, then raise it into
place. Working on a level surface is a major help in laying out the walls flush.
Try to avoid assembling walls on the ground and keep the work surface clean by
sweeping it periodically. 
Most plans include a door/window opening in the wall. Additional framing support
is needed to transfer the structural weight over the opening and down to the floor.
This framing is done with trimmer, king and cripple studs, and a header. 
Find
the header length by measuring between the king studs. In our case, the headers
consisted of two 2x10 boards. From the king stud side, nail the header to each
king stud. 
Exterior sheathing, either 4x8 (or 4x9) oriented strand board or plywood sheets,
is nailed to the framed wall. 
Now the wall is ready to be raised. This may require some extra muscle, so get
a few people to help out. 
When
the wall sections are nailed together, additional corner bracing is needed until
the roof is framed to keep the walls from swaying.