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Erecting the walls, the most impressive stage in the construction of an addition, is also the simplest. The process differs from standard wall construction only at the joint between the house and the addition wall. - Aligning Ceilings: Studs for the addition wall must be the same length as those in the house if the ceilings are to match in height. To determine the correct length, make a small hole through the ceiling of the room in the house next to the addition and measure vertically from a ceiling joist to the finish floor; subtract the distance between the finish floor and the bottom of the studs and then subtract 3 inches for the double top plate of the new walls. - Wall Considerations: Generally studs are made from 2-by-4 lumber spaced 16 inches apart. Some prefer 2-by-6s spaced 24 inches apart, which not only allow thicker insulation in cold climates but call for fewer studs and consequently fewer holes drilled for utilities. Whatever the dimensions, make sure the stud lumber you purchase is straight. In building, plumb the addition walls. Compensate for any tilt in the wall to which you are attaching the addition by angling end studs and adjusting the lengths of top plates. When framing rough openings for doors and windows, procedures vary for bearing and nonbearing walls. The sides supporting the addition roofs rafters are always bearing walls; others are usually nonbearing. CAUTION--- Before cutting into the wall of your house, check siding for signs of asbestos or lead. TOOLS:
MATERIALS:
SAFETY TIPS: When you are hammering or sawing, earplugs provide protection against loud noise, goggles against flying debris. A dust mask reduces inhalation of particles when you are cutting into the house or the roof. MAKING THE INCISIONS 1. Marking the siding. • If an addition wall will meet a corner of the house, snap a single vertical line about 10 inches from the corner. • Cut the siding along the line with a circular saw set to the thickness of the siding (Step 2), then pry away the exterior wall covering between the cut and the corner. • For other intersections between new and old walls, snap a chalk line vertically on the siding inch outside the edge of the addition platform— the area covered with subflooring. Snap another vertical line about 12 inches from the first . • Cut along both of these lines and remove the wall covering. • Repeat the chalking and cutting sequence at the other side of the addition. 44 2. Removing the cornice. If the roof overhang extends below the planned height of the addition walls, you must remove the section of roofing material over the addition platform to expose the roof sheathing. • With a framing square, extend the outer edges of the openings cut in Step 1 onto the frieze board, soffit, fascia board, and roof sheathing. • Cut the frieze board along both lines with a reciprocating saw held vertically, taking care not to disturb the adjoining top plates. Pry away the section of frieze board between the cuts. • Rotating the saw to a horizontal position, cut the soffit and fascia board along the lines , then pry them away. If lookouts supported the soffit, pry them off as well. 3. Cutting off the overhang. • At the outer edge of one of the gaps in the siding, hold a 4-foot carpenter’s level vertically, tight against the outer edge of the house-wall top plates. Slide the level up until it reaches the roof sheathing; drill a 0.25-inch hole at that point vertically through the roof. • Follow the same procedures for drilling a second hole at the outer edge of the siding gap at the other end of the addition. • Snap a chalk line between the two holes. • Cut the roof sheathing along the lines with a circular saw, and pry it away from the rafters. • With a level and pencil, mark a vertical line across each exposed rafter, even with the top plate’s outer edge; trim rafters with a reciprocating saw. 45 PREPARING THE ATTACHMENT POINTS Reinforcing a balloon-frame wall. • To attach an addition side wall to a balloon-frame wall between studs, be gin by removing the interior wall covering behind the slot in the siding. • Toenail 2-by-4 blocks between ex posed studs every 2 feet, 1.5 inches from the outside edge of the studs. • Nail a 2-by-8 to the blocks where the addition wall will meet the house wall, then nail the siding to the 2-by-8. Braces for platform framing. Except at corners of the house, install extra studs to reinforce the wall where addition side walls will meet it. The illustration at left shows the case where the side wall meets the house between studs. If the side-wall intersection coincides with a house stud, incorporate it into the structure. • Slide a stud into the house wall through the slot cut in the siding, and toenail it to top and sole plates, flush with the cut edge of the siding. Outside, nail the siding to the stud every 6 inches. • Toenail a second stud alongside the first, set ting its face flush with the outside edge of the house plates. • Place a third stud against the second to form a U-shaped structure, toenail the stud to the house plates, and then face-nail it to the second stud. 46 Tying into a masonry wall. • Lay a 2-by-4 on the platform as a spacer, then stand a stud on it, flat against the house wall and flush with the addition platform. • Mark the stud at every fifth mortar joint, then drill 9/16-inch holes through the face of the stud at the marks. • Hold the stud against the masonry flush with the outer edge of the platform, atop the spacer block. Plumb the stud with a carpenter’s level and fasten it temporarily with 3.5-inch masonry nails. • Secure the stud as a template and drill 0.25-inch marker holes into the mortar joints. Remove the stud, and with a 0.75-inch masonry bit, bore holes at the marks to fit 0.75-inch lag shields in each hole. Then install the lag shields. • Prepare a stud for the other edge of the plat form in the same way, and lay both aside for later inclusion in the addition side walls. 1. Laying out the plates. • If your addition has a crawl- space foundation, measure and cut straight 2-by-4 top and sole plates for each side wall to fit between the sole plate of the house and the edge of the platform. For an addition on a concrete slab foundation, unbolt the sole plates that you installed when the slab was poured and cut top plates to match. • Set the top and sole plates side by side along their respective walls, and measuring from the ends next to the house, mark locations for studs, windows, and doors (above). • Determine the width of door and window rough openings from manufacturers’ specifications, and mark for jack and king studs beside each. ASSEMBLING THE WALLS 2. Nailing walls together. 48--- • Butt-nail studs to the top and bottom plates at layout marks, omitting the studs for each door or window. • For the outer ends of the plates, make a post from two studs separated by 2-by-4 spacer blocks . • Butt-nail the posts in place. 3. Framing the rough openings. Rough openings for both doors and windows, whether in a nonbearing wall—one that rafters won’t rest on—or a bearing wall, begin with jack studs cut to the height of the opening and nailed to full-length studs called king studs. These assemblies are then nailed into the wall at the locations marked earlier. In a nonbearing wall, the tops of the jack studs are spanned by a header made of two 2-by-4s, with short cripple studs spaced 16 inches apart filling any gap between the header and the top plate. In a bearing wall, a stronger header, built to the specifications, is required— followed by cripple studs above as needed. A window opening requires a sill, which consists of a 2-by-4 evenly supported on cripple studs. • After framing a side wall, tilt it up right and, if you are building on a slab, onto the anchor bolts. • While a helper holds the wall in position at the side of the addition, brace it with 2-by-4s tacked to every fifth stud and 2-by-4 blocks nailed to the slab or platform. • For a foundation with a crawl space, nail the sole plate to the closely spaced joists at the sides of the addition with 3 nails, staggered and spaced 8 inches apart; on a slab foundation, reinstall the washers and nuts on the anchor bolts. 4. Tying the wall to the house. 49--- • While a helper holds a 4-foot level against the side of the end stud of the addition wall, push the stud in or out until it’s plumb. • Except in masonry walls, drive staggered 3.5-inch nails through the face of the stud either into the reinforcing studs installed earlier or into a corner stud of the house. In a masonry wall, fasten the predrilled stud to lag shields with 0.5- by 3.5-inch lag screws and washers. • In a platform-framed house, toenail the top and sole plates of the addition wall to those in the house wall. • Repeat Steps 1 through 3 to erect the other side wall of the addition, then build the end wall—including corner posts and bracing—to fit between the side walls. • Check that end-wall corners are plumb. 5. Straightening the walls. • To eliminate bows in the top plate, first stretch a mason’s cord across the surfaces of 2-by-4 blocks tacked to the top plate at each end of an addition wall. • Have a helper free the bottom of each brace along the wall. • Holding a 2-by-4 block between the cord and the top plate, push or pull the wall until the cord touches the 2-by-4 without bowing, then have your helper re-nail the brace. • Adjust the other walls similarly. • When the walls are straight, nail the studs at each end of the end wall to the corner posts of the side walls. • Cut a second top plate for the end wall long enough to completely overlap the top plates of the side walls and nail it to the top plates of all three walls. • Nail a second top plate to each of the side walls. 2 x 4 BLOCK 6. Sheathing the walls. 50--- • With a helper, hold a sheet of 0.5-inch plywood horizontally against the studs. Rest the bottom of the plywood on the foundation and force one end tightly against the house-wall sole plate. • Fasten the plywood to the studs, the sill plate, the ledger, and the band or header joist. Use 2-inch nails spaced 6 inches apart around the edges and 12 inches apart in the center of the sheet. • Continue the sheathing horizontally around the addition, leaving 1/8-inch between sheets for expansion. • At a window or doorway, nail the sheathing in place, snap a chalk line along the edges of the opening, and cut the sheathing with a circular saw. • Start the second course with a piece of plywood 4 feet square in order to stagger joints between sheets. • At the third course, cut sheets to the width required before nailing them up. ==A GLASSED-IN SUNROOM== Sunrooms allow sunlight through their glass walls to warm a house in winter and provide unmatched ventilation in other seasons. Furthermore, plants grow well in the green-house-like environment there Best on a southern exposure, a sun- room is generally built on a concrete slab under a shed roof, and is fitted with awning and jalousie windows. The walls resemble the stud walls that are shown on above, with one important difference: a continuous header runs across the top of each to relieve the windows, which are not strong enough to serve as weight-bearing components of a structure, of any role in supporting the roof. The headers are supported at the ends by jack studs nailed to 4-by-4 corner posts and combine the functions of rough-framing headers and conventional 2-by-4 top plates. Because the slightest sagging of the structure could cause windows to bind or even break, a sunroom requires assistance from an architect or structural engineer in specifying header dimensions, as well as the size and spacing of studs. |
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Tuesday, April 1, 2014 1:03 PST