Rebuild an Old Porch | |
A porch is an architectural feature worth preserving. Like most exterior areas of a house, it is vulnerable to water damage and eventual rot. Repairing or rebuilding one is a straightforward project. Here are the basic steps involved. Support the Roof Unless a porch is open, its roof must be supported before any major repair work can be done to the joist system. Forget about jacks; the easiest way to support a porch roof is with a system of temporary 2x4 or 4x4 posts. Place a post next to the existing posts or at 10-foot intervals. Nail a piece of 2x4 to the underside of the roof header. Cut the posts about 6 in. longer than the distance between the 2x4 and the ground. Notch one end of the post to fit the 2x4 cleat and place the other end on a 2-foot section of 2x8. Drive the post toward the porch with a sledge hammer. When they're tight, toe nail the temporary posts to the base and cleat. Joist Layout On our 6 ft. x 16 ft. porch, the area between the first joist and the house was vulnerable to water damage. An aluminum bracket was used to hold the joist away from the house. The bracket was bolted to the band joist or sill and the first joist was attached to the bracket, keeping it away from the building. A header was placed in the center of the porch to keep the spans under 10 ft. so 2x6 joists are used. (Check with your local building department for help sizing this framing lumber.) Level the Deck A porch should slope away from the house to promote drainage. On a small porch like ours layout was easy. Temporarily support the front beam on the old footings or make some temporary posts. Then nail the headers (porch ends) to the rear beam attached to the house or aluminum brackets and the front beam. Raise or lower the front beam until it's about 1 in. lower than the rear. When these members are set, repair the old piers or make new footings and piers. Frame the Deck: Install the central header and then the floor joists. Use galvanized joist hangers on 12-in. centers to support 3/4-in. tongue and groove fir decking. To extend the life of the decking, apply a water sealer to the backside of the fir, especially at the ends of the material. Then toenail the decking to the joists with 6d galvanized finish nails. Reset the Columns: Coat both ends of the old roof support columns with a water sealer and then reset them on aluminum column supports. These aluminum pads raise the posts off the deck and prevent water damage. Building the Foundation: Constructing a footing and pier for a small porch is not difficult. The old piers are there so the layout is already done. The piers and footings for a small porch don't require a large amount of concrete so it's practical to use ready-to-mix concrete and hand mix it. Most building codes require footings to be at least 8 in. thick and twice the diameter of the pier. They must be placed below the frost line. If sections of the porch have to be completely rebuilt, it's easier to dig and pour the new footings before the porch joists are replaced. Then frame up the porch, level the deck, and build the pier form right under the beams. Make this form strong enough to support the porch so you can continue working on the porch as the concrete cures. If the porch joists and decking don't have to be totally replaced, you might be faced with the problem of placing a pier under the existing structure. Excavating for and pouring the footing is not too difficult, but filling a form with concrete that is positioned under the porch is a challenge. A solution is to use an 8-in. diameter cardboard builder's tube form. Cut away the front of the form so you can fill it. Purchase a section of this form tube at least a foot longer than needed. Cut the tube to length and then cut a small U-shaped opening at the top so you can shovel in the concrete. Cut the extra foot of tube lengthwise so it will slide over the form. Place the form under the beam with the opening facing outward. Fill the form with concrete by shoveling it through this opening. Add reinforcing bar if required by the building code. When the form fills raise the sliding section. Use a stick to work the concrete into all areas of the form. Over fill the form to be certain that it is completely full. Wait a week to strip off either the tube or pier form so the concrete has time to cure. It might be necessary to shim the deck up slightly because concrete tends to shrink up within the form. Cover the top of the pier with an aluminum termite shield. Written by the editors of HouseNet Copyright HouseNet, Inc. |