Proper nailing pattern for reverse board and batten
Kail_Z
| Posted in Energy Efficiency and Durability on
I am in climate zone 4C and am planning on installing douglas fir, rough cut, kiln dried, and stained reverse board and batten on the home I am trying to build. I was hoping to receive some advice on the proper nailing pattern for reverse board and batten. Most things i find deal with green standard board and batten. I was planning on using screws. Would deck coated screws eventually bleed through and stain the wood? Do I need to use galvanized or stainless? I was thinking of using the deck coated torques finish head screws, is this a bad idea? Thanks for the advice.
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Replies
Kail,
Reverse board and batten poses problems that the standard way of applying it doesn't. Usually the wide boards are centre nailed, or nailed on one side only, allowing them to move behind the battens, which also serve to restrain their tendency to cup.
With the reverse version you don't have any option but to fasten each side of the boards if the cladding is going to be at all water resistant. You don't want these nails (or screws) to penetrate the battens behind. Centre nail the battens and nail the boards about 1/2" in from the ends of the battens behind so they are still free to move.
Kiln dried material may pose the same problems as green wood in that it will move as it takes on moisture until it reaches an equilibrium with the outside levels. You may want to sticker it on site for a while before installation.
Although I've said "nail", torque head deck screws will be fine. No need to use stainless steel.
Kail,
Malcolm gave you good advice.
Here are two images with fastening advice. (Click on an image to enlarge it.)
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I'm learning from Malcolm and Martin's answers. To check my understanding, and perhaps help others understand, I'm going to try to explain what I learned, starting with what was new to me, and then reviewing the basics.
With reverse board and batten, aka batten and board (or nettab dna braob), at first glance it might seem that the functionality of allowing expansion/contraction is undermined. But as long as the screws for the boards miss the battens, and are thin enough to be a little flexible, some expansion can be accommodated by the screws bending left and right. That might not be enough for building with green boards, but it's probably fine for dry lumber. One nice thing about this design is that it provides air space behind for better drainage and drying, so it might be the design of choice for durability if you are building with dry boards.
Board and board would save some material and some trouble rippping down boards into battens if you start with all boards, but it has air space behind only half the boards.
Review of the basics:
The designs are intended to allow the wood to expand and contract laterally, and to keep it flat. That's most important for green wood drying in place, to allow shrinkage. Second to that might be freshly kiln dried wood or kiln dried wood that has been kept in a dry place, that would expand as it takes on ambient moisture.
For well air dried wood, or kiln dried wood that has been acclimatized to the outdoor air where it will be installed, there's still seasonal variation in humidity and thus moisture content that needs to be accommodated, but it's not as drastic.
In Martin's first image, type board and batten, the boards are held flat in three places--the nail in the middle and held down by the battens. It can freely expand and contract by sliding under the battens. In the first version in the second image, you are counting on the movement between the two 1/3 width spaced srews to be small. That will probably work for many cases but it seems like extra work for worse reliability. The second version in the second image, compared to the first in the first image, has the possible advantage that some of the fasteners are hidden, but has the disadvantage that the sliding is all on one side, so it has to slide twice as much there, and the disadvantage that it's only held down in two places rather than three, so it might not stay as flat. All in all, almost but not quite good as the first option in the first picture.