Pro Catalog - Curtis Lumber

Cedar Siding Installation
Stud
1/8"
Expansion
gap
Building
paper
Sheathing
Overlap
undercourse
not less than
1"
Nail clears
tips of siding
Nails must
penetrate
solid wood
1 1 ⁄2"
Start with
furring strip
Stud
Building
paper
Sheathing
Expansion
gap 1/8"
Nails must
penetrate
solid wood
1 1 ⁄2"
Finishing, Painting & Staining – Information For Cedar Siding
Discoloration
Cedar enjoys a well-deserved reputation as a wood that takes and holds
a range of finishes for extended periods. Nevertheless, the normal life of
a finish will be shortened by degradation and discoloration. The causes
of discoloration, though not in themselves a failure of the finish, often
require remedial treatment.
Dirt
Dirt is the most benign cause of discoloration and not usually a problem.
A periodic cleaning with a mild detergent solution will usually restore the
surface finish.
Mildew
Mildew applies both to the fungus and to its staining effects on both the
finish and the wood. Mildew is a common cause of discoloration of paint,
solid-color stains and natural finishes. Restaining does not solve a
mildew problem. When it is time to refinish, clean off the mildew with a
commercial mildew-remover then refinish with a coating that contains an
effective mildewcide.
Extractives Bleed
Extractives bleed that discolor the finish is usually caused by moisture.
To control stains caused by extractives bleed, moisture problems must be
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Bevel Siding
Spacing for the siding should be laid out beforehand. The number
of board spaces between the soffit and bottom of the lowest piece
of siding at the foundation should be such that the overlap is as
per the table below. The wider the siding, the greater the overlap
can be.
Start with the bottom course using a furring strip to support the
lower edge. Each succeeding course overlaps the upper edge
of the previous one by 1 in. (25mm). Rabbeted patterns are selfspacing,
but leave 1/8 in. (3mm) expansion clearance. Where
possible, the bottom of the board that is placed across the top
of the windows should coincide with the window cap.
Bevel siding should be face nailed to studs with 1 1 ⁄4 in. (32mm)
penetration into solid wood using one ring shank nail per bearing
spaced at a maximum of 24 in (610mm) on center. Place nail just
above the overlap. Take care not to nail through the overlap of two
pieces (see table below).
Do not reduce the siding overlap recommendations given. To do so
could result in damage from wind-driven water.
Butt joints between boards should be staggered and made on
studs. Fit siding snugly to other pieces and to trim.
Recommended Overlap for Bevel Siding
Imperial Overlap
Nominal Actual Inches
4
6
8
10
12
31 ⁄2
51 ⁄2
71 ⁄2
91 ⁄2
111 ⁄2 1-2
Note: Do not exceed 2" (51mm) overlap. Use the larger overlaps for unseasoned sidings to allow
for shrinkage and expansion. Take care not to overdrive fasteners when using larger overlaps.
eliminated. Mild staining is often washed away by rain over a period of
weeks. In sheltered areas of the building where the stain persists, it may
become darker with age and more difficult to remove. If washing with a
mild detergent solution does not work, a commercial cleaner may help.
Iron Stains
Iron stains may appear in two forms: the reddish brown discoloration
caused by rust, and blue-black discoloration caused by the reaction of
iron from nails and other metal objects with extractives from the cedar.
To prevent these stains, use only hot-dipped galvanized aluminum or
stainless steel nails when fastening cedar.
Water Stains
Water stains often occur in combination with extractive bleed and mildew
growth. These stains can be difficult to remove. Scrubbing the wood with
an oxalic acid solution is sometimes effective.
Caution: Handle oxalic acid solution with care as it can be harmful.
Chalking
Chalking is a property of the paint, not the cedar. It occurs when a paint
film weathers or deteriorates, releasing pigment particles that act like a
fine powder on the paint surface. Chalking is a common cause of fading
of tinted or colored paints.
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