Installation Guide

Primed MDF Shiplap
(intended for interior use only)
General Shiplap Instructions
1. Let Pac Trim® Shiplap acclimate before installation. Pac Trim®, like all wood products should
be conditioned to an indoor environment 48 hours before installation. Upon delivery, stack
Pac Trim® on 2x4’s off of the floor and protect from outdoor elements.
2. If applying to sheet rock/dry wall, mark stud location for nailing or you can apply with
construction adhesive (i.e. liquid nails, PL or Loctite) running beads using 16” spacing.
3. Applying directly to studs use 18 gauge 1 ¾” long brad nails with a nail gun.
4. Properly setting the first piece will ensure a uniform application and the desired result.
Measure from the ceiling down to the top edge of the board in several places to ensure
proper alignment before nailing.
5. Nail through the top flange (the top flange is the longer flange). A second nail should be
placed through the bottom face of the board, approximately 1” from the bottom edge.
When installing shiplap over plaster or drywall, the walls need to be in good condition.
6. In runs longer than 16’, stagger the second row so end joints do not line up.
7. If applying vertically, add furring strips to the studs every 24”, use the same size brad
nails.
8. Filling the nail holes with painter’s putty or a light spackle will reduce nail holes from
showing up in the finished wall.
Shiplap can be applied directly to studs or over sheet rock*
(*Please check local building and fire codes to ensure requirements are met when applying directly to the studs)
Note: Like all wood products, MDF absorbs and desorbs moisture with changes in relative
humidity. The normal range of interior humidity is 40 to 80%. The industry standard for
maximum expansion and contraction of MDF due to changes in relative humidity from 40
percent to 85 percent is .3 percent. Thus, some expansion and contraction of MDF shiplap
should be expected.
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