Installing Hardboard Siding

Follow these recommended installation techniques for your next high-quality hardboard project.

February 28, 2001

Hardboard siding is a high-quality choice for any remodeling project. Following are recommended installation techniques for hardboard lap siding from the American Hardboard Association:



  • Lap siding may be applied over sheathing or, with an approved weather-resistive barrier, direct to studs spaced 16 in. on center. Wall design should provide moisture protection equivalent to a vapor-retarding system having a rating of 1 perm or less installed on the warm (living) side of the insulation. Allow a minimum 6 in. space between the siding and the ground or any area where water may collect.



  • Install a starter strip, approximately 11/2 in. wide and the same thickness as the siding, flush with the bottom edge of the sill plate. Extend the siding at least 3/4 in., but no more than 2 in., below the starter strip. Nail the bottom edge of the first course of sidingù16 in. o.c. maximumùthrough the starter strip and into the sill plate.



  • The second and all succeeding courses of siding must lap the previous course with a minimum of 1 in. Nail 3/8-in. minimum from the bottom edge and into each stud, nailing through both courses.



  • Install shim strips for continuous horizontal support behind the siding wherever it is notched out above or below openings. Install a drip cap or flashing above openings. Leave a 3/16-in. minimum space between the siding and windows, door frames and corner boards. Caulk these spaces with non-hardening, mildew resistant exterior grade sealant.

    Also See:

    Product Watch: Siding

    Estimating Redwood

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