Tips & Tools
Application, Priming, Nailing and Pattern Selection
Wood shrinks and swells with change in moisture content. To minimize dimensional
change after installation, install siding at a moisture content that matches with local
climate as closely as possible. If climate in a particular region causes wood to maintain
8% to 13% moisture content annually, then the most ideal siding would be installed at a
moisture content within that range, and the material would be stored, stickered and
protected for a week to ten days prior to application.
If unseasoned materials are used, the following considerations are suggested:
1) allow for shrinkage; 2) use as narrow width as possible; 3) use patterns which allow for some shrinkage 4) and in-place seasoning before application of finish or 5)pre-staining.
Often material which has been properly seasoned, stored and handled, will pick up
moisture after installation and prior to painting. Later, when the siding releases its
moisture, joints may open up or buckling may occur.
Extra protection can be given the siding by priming or prefinishing all sides, edges and
ends after it has reached climatic balance and before it is installed. Prefinishing can also
minimize objectionable unfinished lines where joints open up due to face width shrinkage.
Use single Finish nail for 6 inch widths or less.
Wider widths, face nail twice per bearing.
1. Some patterns allow for greater dimensional change than others. Patterns such as bevel
siding and channel rustic have the capability of greater joint movement than patterns
such as tongue and groove.
2. Apply siding over building paper.
House construction features that will minimize water damage of outside paint are: (a)
Wide roof overhang, (b) wide flashing under shingles at roof edges, (c) effective vapor
barriers, (d) adequate eave troughs and properly hung downspouts, (e) exhaust fans to
remove excessive moisture, and (f) adequate insulation and ventilation of the attic. If
these features are lacking in a new house, persistent paint blistering and peeling may
occur and the structure then would best be finished with penetrating pigmented stains.
The proper application and nailing of wood siding does much to improve the appearance
and durability of both wood and paint by reducing the tendency of the siding to split,
crack, and cup with changes in moisture content. When possible, depending on the
siding pattern, siding boards should be fastened so boards are free to shrink and swell,
thereby reducing the tensile stresses that develop at fasterners.
Multiply square footage to be covered by factor (length x width x factor).
*Allowance for trim and waste should be added
Nails and Nailing
Good nails and nailing practices are a must in proper application of wood siding. Nail
locations are included under individual patterns. However, the following data about nails
will be very helpful in the selection and use of the right nail for the right use.
The following requirements are essential for nails used on wood siding:
1. Rust-resistant, preferable rust-proof. See types of nails recommended.
2. Should not cause splitting even when driven near end or edge of siding.
3. Should have adequate strength to avoid the need for pre-drilling.
4. Nails should be able to be driven easily and rapidly.
5. A nail should not emerge or pop at any time after being driven flush with
6. The nail head should not cause an unsightly visible pattern on the sidewall.
7. Nail butt joints at the stud or blocking.
8. Nailing is preferred over stapling.
Types of Nail Recommended
1. Stainless Steel
2. High Tensile Strength Aluminum Nail. This nail is corrosive-resistant and will
not tend to discolor or deteriorate the wood siding. It is an economical nail
when the nail count per pound is considered, although it is somewhat more
expensive than the common galvanized.
3. Galvanized Nail.
a. Hot-dipped galvanizing. Degree of coating protection varies.
Common iron nails or poor-quality galvanized nails corrode easily and will cause
unsightly staining of the wood and paint. When the wood is to be left unfinished to
weather or finished naturally with light-colored penetrating stains or water-repellent
preservatives, only aluminum or stainless steel nails should be used.
Nail penetration and Spacing
Suggested sizes are minimal and should be longer when siding is installed over other
than wood sheathing and/or sheathing and studs. Recommended penetration into a solid
wood base is 1 ½, 1 Ό with ring shank nails.
Vertical siding should be nailed to blocking or other wood framing members not over 36
on center when face nailed, and 32 on center when blind nailed.
Horizontal siding should be nailed to studs at 24 o.c. maximum when applied over solid
sheathing and 16 o.c. maximum when applied without sheathing.
Many nails are smooth shanked and will loosen under extremes in temperature changes.
Increased holding power may be obtained by using a ring-threaded or spiral-threaded
nail shank. These particular shanks are readily available.
The most commonly used nail points include:
Blunt reduces splitting
Diamond most commonly used
Needle tops in holding but tendency to cause splitting
For the best possible holding power with the least splitting, a blunt or medium diamond
and a blunt or medium needle with a ring-threaded shank are recommended.
**Information obtained from USDA Agriculture Handbook, No. 72, Published by the U.S. Forest Products
Laboratory, Madison, Wisconsin. As good results depend upon workmanship and subsurface upon which
siding is applied, NeLMA is in no way responsible for performance of wood siding.
Related Document: Siding Installation Information.pdf