First Floor Additions: More Room More Happiness
(Part Four: Roofing - Topping Your Addition Off )

by: Liz Roberts

It’s now time to think about adding a roof once the addition’s framing is up. A contractor can be hired or the job can be turned into a do it yourself project. Whichever way is chosen, make sure that your roof will be durable and weather resistant. No one likes a brand new addition to leak like an old shack. With the other addition projects, be cautious, careful and conscientious. Don’t skimp on materials and have the right amount of extra help to make this project an easy one.

If the main house’s roof is fifteen years or older then consider roofing both at the same time. By doing this it eliminates the need to reshingle each section at different times along with providing a more uniform look to the entire house. Roofing both the original building and the add on also cuts out the search for matching roofing tiles.

Consult your blueprints when starting. The exact measurements will be there and you’ll use these for your guide. Also make sure you have the right equipment and hardhats if necessary. Remember one wrong or stupid move could wind up in a visit to the ER.

Like your addition’s main part, the roof will also have to be framed. You can buy prefabricated roof trusses or cut and assemble a roof frame from scratch. Basically roof trusses are a prebuilt series of structural members designed to carry a roof’s weight to the outside walls. Your supplier can handle everything there is for your roof. Begin at one end and drive a nail ¾” in from the end. Now hook your measuring tape to this nail and start measuring and marking every 24”. Draw X on the sides of the marks nearest your nails. Use metal rafter ties to make installation easier .

To put your truss on your framing, you’re going to need help. Lift one end of it and carry it up the ladder. There should be an extra pair of hands to help with the lifting and to steady you. Place it upside down next to the end set of metal rafter ties. Then set the other end into position on the opposite walls. Flip the truss right side up, sliding it into place. Use a leverage board to help swing the rafter into place. Now nail the rafter tie in place over each X where the rafter connects with the cap plate. An assistant will have to hold each truss into position. Meanwhile you will have to nail a temporary brace to the unit across the sloping top chord. Continue this procedure until all of your rafters are in place.

Sheathing is one of the most important beginning steps in roofing. You can use plywood, particle board, wafer board sheathing or simply 12” by 48” slats. Most builders rely on particle board. This is the most inexpensive and easiest to apply. Also choose an exterior CD grade of plywood. Thickness on it and on wafer board can range anywhere from 3/8” to ¾”. (depending upon your local code). To figure out how much you’ll need divide the total number of square feet of roof surface by 32 square feet of roof surface , adding an extra fifteen percent for waste. The only tool you’ll need at this point is an air compressor or a nail gun.

Remember to check all rafter ends or tails, making sure they’re on a straight line. If the walls below are crooked, then so will be the rafter tails. This problem can be corrected however by just popping a chalk line across the tails. Trim them with a saw before adding your sheathing. This is important because the building line will be very noticeable when viewed from below.

Start applying the sheets from the roof’s bottom (or eaves). Work your way up to the ridge. If the roof is not on in 48” increments , you’ll have to rip cut the last course at the top. It extremely vital that the sheathing at the eave is exactly perpendicular to your rafters so that the sheets will met at the rafters’ centers. Also make sure that it’s also perpendicular to the rafter tails(not flush). You can cut a tapered piece of the sheathing to fill in at the eave if needed. Building codes (which vary from area to area) require nails every six inches and twelve inches in the field. Again a chalk line is required here. Pop it across the sheets to mark the center of the as your guide. Don’t nail the edge rafters where this meets until the adjoining sheet is in place. This enables you to move the rafter a bit if needed so that the sheathing meets in the center of the rafter. Stagger the joints of each course. Do this by cutting a panel in half and then use these half sheaths to start every other course. You may need to get special hardware clips which will add stability to the splices where the sheets meet between the rafters. Carefully( not to mention cautiously) work your way up to roof’s peak For your safety it is best to a 24” by 48” toe board horizontally across the lower panel of the sheathing. This will act as a brace as you work your way up to the roof’s peak. Sheath one slope of the roof at a time, ripping the top course to the needed ridge of the roof. When one slope is completely sheathed, pop a chalk line down any slope edge that needs to be cut at angle. Cut these panels before you nail them in place. Set your circular saw to the proper depth and now saw off the excess overhang. Repeat this for the other slopes.

Once your roof construction has gone this far, you can step back and take a breather. You’ve just been through the hardest phases. However they are the most important and guarantee a solid , well built roof.

Next part of the series finishing the roof