How to Hide Seams on T1-11

Measure 1/2 inch below the sill plate on opposite sides of the house and snap a chalk line between the two marks. The sill plate is the horizontal board that sits directly on top of the masonry foundation.

Look at a sheet of T1-11 siding. Notice that the edges on the long sides are slightly different. One edge features a groove, followed by a narrow flat strip. This is the under-lap edge. The other side has no visible difference when viewed from the front, but if you feel beneath the edge, you’ll discover a recessed strip. This is the overlap edge.

Place a sheet of T1-11 vertically at the corner of the house, positioning the overlap edge with the corner of the house. Align the bottom of the panel with the chalk line. The under-lap edge should extend to the center of a wall stud. This is known as “breaking on center.”

Nail the T1-11 panel in place by hammering one 8d galvanized nail every eight inches horizontally along the sill plate.

Add a vertical row of nails, spaced eight inches apart along the overlap edge of the panel, 1/2 inch in from the edge. Do not insert nails into the under-lap edge of the panel.

Attach the center of the panel (the plane) by inserting additional horizontal rows of nails, spacing each row of nails eight inches above the previous row. Each of these nails must hit a wall stud. Standard wall studs are 16 inches apart. Once again, do not insert nails into the under-lap edge, even though it breaks on a stud.

Place a second T1-11 sheet next to the first sheet, and slide the overlap of the second panel so it covers the under-lap of the first panel. The panels should butt snugly. The bottom of the panel should align with the chalk line.

Insert galvanized 8d nails, 1/2 inch away from the overlap edge. These edge nails will go through both the overlap of the second panel and the under-lap of the first panel. Once you nail the second panel, the seam will not be visible.

Install the rest of the T1-11 panels in the same fashion, cutting the last panel to fit, using a circular saw.

Attach a strip of outside corner trim to cover the raw panel edges and nail in place with 8d galvanized nails every eight inches on both sides of the trim.

Apply a coat of exterior primer and at least two coats of exterior paint over the siding to protect it from weathering and to hide the nail heads.