The performance of 35 finishes (clear water-repellent preservatives; lightly pigmented, water-repellent preservatives; semitransparent stains; solid-color stains; and paints) applied to newly planed, vertical-grained; factory-planed, flat-grained; or saw-textured, vertical-grained western redcedar bevel siding was evaluated for cracking, erosion, and general appearance over 14 years of outdoor exposure at two sites (Madison, WI, and Gulfport, MS).
Nor had any work been done to compare the performance of these new low-VOC finishes on flat-grained bevel siding from second- and third-growth forests.
We report here the performance of 35 finishes used in 49 finish systems on newly planed vertical-grained; factory-planed flat-grained; or saw-textured vertical-grained western red-cedar bevel siding.
The flat-grained bevel siding was all heartwood select-knotty grade with small tight knots having approximately two to three growth rings per cm.
FINISHING -- Within each type of bevel siding (factory-planed flat-grained; newly planed vertical-grained; and saw-textured vertical-grained), the 4-ft boards were randomized, and three boards were used for each finish system.
For example, the service life of finish C-5 (solid-color oil stain, Figure 2) was about nine years on newly planed vertical-grained, 13 years on factory-planed flat-grained boards, and more than 14 years on saw-textured vertical-grained lumber.
In general, we found little difference between the newly planed vertical-grained surface and the factory-planed flat-grained surface with some exceptions noted in the following subsections.
However, in general, the type of surface (smooth-planed or saw-textured, vertical-grained or flat-grained) had little overall effect on the general appearance ratings of these finishes (Group A-1 to A-14), primarily because of mildew growth.
In some cases, finishes on the factory-planed flat-grained siding gave better performance than on the newly planed vertical-grained siding, but this was not universal.
Note that the service life was higher at Gulfport and Madison for the factory-planed flat-grained siding than for the newly planed vertical-grained siding.
Little apparent difference was evident between the WRP-treated and untreated for the newly planed vertical-grained siding and the factory-planed flat-grained siding.
There was little difference between the factory-planed flat-grained siding and the newly planed vertical-grained siding after 14 years of outdoor exposure near Madison and Gulfport.