Board and batten siding is a time-tested exterior used in both residential and commercial structures. Although some manufacturers describe sheet materials as board and batten siding, true board and batten siding uses actual lumber. The boards used in board and batten siding must be spaced apart to allow for expansion and contraction, as well as ensure the fasteners penetrate the studs. Today, we will discuss the reason for board and batten spacing, how it is calculated, and why.
What Is Board and Batten Siding?
Board and batten siding describes using a combination of wide and narrow boards, one atop the other, to create a watertight exterior for a structure. During installation, wide boards are attached to the building vertically, with a space in between each board. Then a narrow strip, the batten, is installed over the space between the boards to prevent water from reaching the framing. In most installations, longer battens will also be installed around the perimeter of the structure, and on both inside and outside corners.
Does Board and Batten Siding Need Spacing?
In most installations, board and batten siding will require spaces between the boards. Spacing is done for a few reasons, which we will discuss here:
Spacing Saves Material
When the professionals install board and batten siding, usually the first step is to calculate the area. To illustrate, let’s say we are installing board and batten siding to an exterior wall 10’ high and 20’ long. After doing the math, we calculate that we’ll need 200 square feet of lumber.
Next, we decide the width of the lumber we will use. In this case, let’s use the typical size, which is a 1” x 10” board. These boards are actually closer to 9 ¼”, so we would need 26 of these boards to span the 20’ distance. However, this does not account for any spacing.
If we add a 2” space between each board and recalculate, we discover we will now only need 22 boards. Obviously, as the space becomes larger, less material is needed. However, we need to be aware of the impact the spacing will have on attaching the siding to the structure.
Spacing Allows For a Secure Installation
Most buildings built from wood, like residential homes, have vertical framing inside the wall called studs. The studs are spaced apart consistently according to the design of the building. In most structures, this spacing will be either 12”, 16”, or 24”. When board and batten siding is installed, best practices require that the fasteners (usually #8 galvanized nails) penetrate the siding, sheathing, and studs.
To ensure that our battens are nailed to a stud, we need to space them so that the boards fall on either 12”, 16”, or 24” centers. Since we’re using lumber 9 ¼” wide, we can use a 1” x 4” batten (which is actually about 3 ½” wide) to cover the gap between the boards and still land on a stud. Doing so ensures the strongest bond between the siding and the structure.
Spacing Creates Channels For Water
Homes built in the last twenty years or so will likely have house wrap installed, which protects the wall sheathing from water damage. However, older homes may have roofing felt, or nothing at all protecting the framing. By adding channels (or spaces) between the boards, we create a channel for any water to escape from, should it get behind the siding.
The same space also allows for expansion and contraction of the wood as the temperature and humidity of the wood change. Wood is porous, so even humidity from the air can cause it to swell, crack, and split. By leaving a space between the boards, the boards can expand and contract as needed without contacting an adjacent board and cracking.
How Do I Know What Spacing to Use For Board and Batten Siding?
There is no hard and fast rule for the spacing of board and batten siding, but many like the appearance of a 1:3 or 1: 4 ratio. For example, if we use a 1” x 10” board, a common batten would be either a 1” x 3”, or a 1” x 4”. The space between the boards in this configuration is often 2”, as this prevents the batten from splitting when a fastener is driven too close to the edge. Using this arrangement also aligns with the stud spacing to allow for a more secure attachment to the structure.
In general, the spacing can be adjusted as needed, as long as there is at least ¾” of overlap of the batten over the board. Using a smaller overlap may allow water to sneak between the boards and allow water to penetrate the siding. Some installers use this spacing for appearance as well, because the look of the project is greatly affected by the spacing of the battens.
For example, if the board and batten siding is to be a prominent feature, the battens are often wider and closer together. Conversely, if the siding is subtle or not a prominent feature, the battens will often be small and further apart. Texture can also affect the visual impact of the siding, so the pros recommend experimenting with different textures and locations to find the perfect material for the application.