Replacing a piece of siding
Our 90-year-old balloon-frame house has 3/4-in. interlocking bevel siding with a tongue on the top of each board fitting into a groove on the bottom of the board above. I need to replace a couple of individual boards and want to know where to look for this type of siding and how to splice in the new boards.
Todd Stine, Seattle, WA
Former associate editor Roe A. Osborn replies: Siding manufacturers can make custom siding to match what you have on your house, but they usually require a minimum order of a few hundred square feet. Because you probably need to replace only a few pieces of siding, the cost of following this route would be prohibitive. Instead, I recommend bringing a small sample of siding to some of Seattle’s older lumber companies. One of them is bound to have handled your siding, and with any luck they still might have a few lengths sitting on a rack somewhere.
When replacing an individual piece of siding, you need to determine how much of the board you want to replace. There are a number of factors to consider. First, of course, is the extent of the defect (the rot or the check) in the board. I always try to go beyond the visible defect by at least one stud bay. The next consideration is the neighboring butt joints in the field. Never create a joint directly above or below from the neighboring siding before I pull them out. Otherwise I risk damaging the siding that’s staying on the house.
Replacing a board is easier if I don’t have to create new butt joints, so if the defect in the wood ends just a few feet from a joint, I’m inclined to take out the entire board. If I need to cut the board to create a joint, I begin by driving any nails in the piece of siding I’m removing (including the joint area) through with a nail set (see drawing). Next, I scribe the cutline by running a utility knife along the blade of a combination square. I cut through the board with a circular saw set at a shallow depth, taking care to avoid damaging the adjacent siding. I finish the cut with the utility knife or with a fine-toothed handsaw. Then I cut out a lengthwise strip about 1/2 in. wide from the center of the piece of siding I’m removing. With that strip taken out, I should be able to pull the top waste section down and out of the groove above and the bottom waste section up and off the tongue below. I make sure the waste pieces are free from the neighboring siding before I pull them out. Otherwise I risk damaging the siding that’s staying on the house.
I cut the replacement siding to length, and I rip off the backside of the groove on the bottom. I slide the replacement board up into the groove above and let the bottom lap over the board below. Finally, I fasten the replacement board at every stud and caulk the butt joints before applying a finish.