Installation of cedar board-and-batten siding
Thanks to some excellent advice from the members here on the GBA website I have progressed well with a re-siding project on my 70’s era house in Alberta. All of the existing siding is being stripped down to the sheathing (Tar paper with stucco and then at some point vinyl was nailed directly over that). As I progress I have come up with a few questions in follow up to my original question and discussion.
My new exterior wall assembly will be a new WRB, then 1.25″ rigid mineral wool, 2×4″ furring strips (I decided to go this route on the recommendation of GBA Editor Brian Pontolilo with the hope of making it easier to keep the furring strips in plane and also the added option of additional rigid 1.25″ insulation in between the furring strips.) and finally kiln dried Alaskan Yellow Cedar board and batten siding to finish it off. (actual dimensions roughly 0.8″x7.5″ boards and 1×2.5″ battens)
In reading about techniques for installing board and batten, it seems there’s more conflicting info out there than consensus, and many different approaches. Given my wall assembly and siding material/dimensions, I’m looking for advice on what the best practice for my installation would be.
1. Spacing of Boards: I had planed on a spacing of about 0.75″ between boards.(Leaving about 7/8″ overlap with boards/battens) Any other considerations to make? Could I go to 1″ spacing or should I consider 0.5″ spacing?) I have seen some installs where boards are nearly butted together with no gap at all. Any purpose to this?)
2. Nailing Pattern: some say putting two nails in the boards can cause them t0 crack over time? Given the width, I’d assume two nails is likely required but am now second guessing. If using two nails should they be evenly spaced across the width of the board or closer to the center? I have seen many new builds recently that seem to nail the edge of the boards only then hide the nails with the batten. Or simply nail on both sides of the batten and directly through the boards to tie everything together. In my mind, nailing close to the edge is just asking for headaches with splitting. Also, doesn’t this defeat the idea of traditional board and batten which allows boards to expand and contract independently if battens are fastened with a single nail through the gap in the boards? Some of these builds seem to be using nails more similar to brads than siding nails. Any idea what’s going on there?
3. Fasteners: Planning on stainless ring shank nails for the boards and debating whether to use screws or same ring shank nails for the battens. I have seen some reports of battens loosening up over time with nails and outward pressure from cupping wood and recommendations to use screws as a more secure fastener. Screws aren’t nearly as aesthetically appealing though. Thinking I’d need 2.5″ nails at a minimum for the battens but maybe 3″ or longer to be safe. Not many siding nailers that shoot 3″ plus nails. Recommendations here?
Thanks for any feedback!
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Replies
Drew,
There are indeed many approaches, as you note.
My thoughts:
1) If you're using kiln dried, definitely leave space between the boards for them to expand. The exact calculations for spacing depends on the starting moisture content, the specific moisture expansion/contraction characteristic of Alaskan Yellow Cedar (google), and the range of experienced relative humidity. But I feel intuitively like your proposed 3/4" gap with 7/8" overlap should cover you on all fronts.
2) I also worry about nails for battens, but I really don't have anything to back that up other than observance of what moving wood is capable of. I also just finished a b&b install with rough-sawn eastern hemlock, which is a different beast than Alaskan cedar I'm think (hemlock is wild-- if alaskan cedar is anything like eastern white cedar, it's much more tame.)
3) I would avoid nailing the outer edges. Go with one nail through the batten, and one through the board. You could probably get away with 2 through the board, but it seems unnecessary, and why risk splitting the edge when the battens hold them in place for you.
4) Consider facing the heartwood to the exterior.
Coming from more of a traditional woodworking background, never using nails or screws to put anything together, than a building background, it is not clear to me why you would use nails or screws through those boards. As you suggest, the battens will hold the boards in place with one nail thr0ugh the middle of each batten passing between the boards.
Nailing (or screwing) the boards in place will increase the risk of splitting. Using two nails across the width will almost guarantee lots and lots of splitting. When a board wants to cup or expand or shrink it will. Without fasteners it will have room to do so without splitting; if it wants to expand or cup and a fastener is in the way it will split around the fastener.
If you really want to nail the boards in place, use no more than one fastener down the center, but I don't really see the point to it.
Your proposed gap between the boards is probably a bit more than necessary, but should be fine. I would use screws, not nails, on the battens, so as to make repairs, if needed, easier to do without destroying the battens.
Make sure the wood is properly dried. If it is kiln dried, leave it outside. preferably spaced on sticks, for a while before using it. Definitely paint the bottom and top edges before installing to retard moisture moving in and out of the boards.
I've never worked with that specific wood, but for pine, I nail only on one side under the batten. For the battens, ring shank holds as well as screws and looks much cleaner.
1/2" gap is more than enough, you just need enough so that the batten nail doesn't catch the edge of the board.
I wouldn't worry too much about repair, when it comes to repairs, the battens will generally need to be replaced anyways.
Back priming and installing over strapping would keep cupping and splitting to minimum.
Thank you for the responses and feedback! Much appreciated.
I suppose the variety of responses illustrates the trouble I'm having deciding on installation technique. I also suppose this is where the true trade 'craft' comes into play and experience/having a good feeling for materials and installation are a big asset!
The Western Red Cedar Lumber Association does describe nailing of board and batten indicating that on boards wider than 8" two nails should be used toward the center of the boards, nailing 2.5-3" apart.
https://www.realcedar.com/siding/installation/profiles/board-batten
I also called the mill where I sourced the cedar and two different people I spoke to had two different answers, of course both thinking their way was the way it should be done.
I live in a drier climate with only a few humid weeks during the summer however cupping of the boards is a concern due to broad temperature and humidity extremes so at this point I'm inclined to go with double nailing of the boards spaced at 2.5" or maybe even 2" to help support the boards. Boards will be installed over 24" OC horizontal strapping.