A few tips on exterior trim and siding
With the rainscreen in place and the exterior trim installed, we can slap up some siding. The essential detail in this step is at the top of the siding course. It is necessary to provide a ventilation channel at the top of the wall so that air can circulate, so a backer strip is installed to bump the top trim out from the siding about a quarter inch.
More bug screen keeps the bees out, and trim covers the ventilation channel.
Siding is run up each side of the door, making sure to keep the courses consistent, so that Will and Ron won’t look like rookies when they get to the top of the door. On small walls like this, a four-foot level is all you need. When siding the whole house, use a builder’s level or laser to set benchmarks at each corner.
Install the siding
Ron begins the siding with a small kickout strip, which is the top of another piece of siding, and he keeps the bottom piece about a quarter inch above the flashing, to prevent capillary wicking.
Again, because this is a small isolated section of wall, story poles are not needed; a tape measure and a couple of levels do the trick.
Notching around electrical boxes, leveling as he goes and keeping an eye on the marks from the other side of the door is done all the way up.
To place a backing box, it is great to line up the bottom and top with siding courses if possible. Set a screw, level the box, and screw it off.
It is also good to not kink wires behind siding, so Ron makes sure the wire is straight before drilling a hole where the wire will go. He sticks the wire in the hole, puts the board on the line, and nails it.
When cutting siding, nibble your way up to the mark rather than trying to get it exactly right the first time. This helps to assure you won’t cut it short by mistake (I keep cuttin' it and cuttin' it and it's STILL too short)
They work their way up the wall to the backer strip.
Two-piecing a long section of trim
Now, Ron can finish boxing out the trim. We decided to two-piece this one not because they didn’t have any trim left that was long enough but to illustrate how to keep water out of walls when piecing together protective trim boards. Make sure the bevel slopes down and away from the wall (as opposed to up and in), and seal the ends with a high-quality sealant. If any water leaks into the joint, gravity will push it down and away.
Notice that Ron lines up the joint before driving the top piece home. It is substantially tacked in place and the lower piece is driven home, and then the top is finished.
The face piece is ripped to width and the edge that will butt the trim is glued. Ron screws the face into the framing and then nails the joint between the two trim boards.
Screw holes are filled with plugs, and the last piece of trim is installed to create the ventilation channel.
—Will Schwarz is a remodeling contractor in Marshfield, VT. This is the fifth in a five-part series following the project from flashing to rainscreen to siding and trim.