Boral TruExterior composite skirtboards blend right into the clapboards above and are impervious to water damage.
Most of the time when I’m adding an exterior skirtboard detail, I do a traditional two-piece assembly consisting of a wide board with a drip cap. In addition to giving rainwater a place to gather and drip without collecting along the bottom edge of a horizontal piece of skirt stock, the cap also acts as a start strip, kicking out the bottom course of siding to match the angle of the courses above. On a recent project styled to match some old Shaker structures, the design called for a simpler one-piece skirtboard that blended right into the clapboards above. The effect is beautiful, but I wasn’t looking forward to cutting the long pieces of skirtboard stock with this custom profile, and knew that without the benefit of the overhanging drip cap I would have to go with a composite trim material if I had any hope of keeping the paint on the trim over the long haul. When, during an unrelated but fortunate internet search, I learned that Boral made the exact skirtboard profile we were trying to re-create, things started looking up. The TruExterior skirtboard is a special-order item at my local lumberyard, and the price came to about $6 per lin. ft. for a 5/4×8 version. The cost is comparatively steep, but much of that is the nature of the beast when choosing fly-ash composite exterior trim material, which is impervious to water damage. If you consider that the same yard sells square-edged 5/4×8 TruExterior trim boards for $4 per lin. ft., I figure I got a pretty good deal on not having to do all that dusty milling on site.
—Justin Fink, editorial director
From Fine Homebuilding #289
More about skirtboards:
Skirtboard Template – Accurately reproduce skirtboards for an existing staircase using a technique borrowed from countertop installers.
Trimming Curved Stairs – Site-laminated handrails, flexible skirtboards, and off-angle miters are standard on winding walkways.