Raw Spruce siding
Hey,
Im in coastal maine, 6a. A couple of years ago I milled the red spruce up that I had on my land and I now have 175@ 18 foot 1×8″ rough sawn boards dried and stacked next to my house, a 1000 square foot single pitched PGH.
I plan on siding with it, raw. There is a 2 foot overhang and a 3/4 inch rain screen. The original plan was to plane it down and cut ship laps on each side and install it horizontally. I recently counted the number of passes that would need to be made to get the boards in shape and was shocked. Cutting the shiplaps with a table saw and planing would be about 7 passes per board for a total of 1200 passes.
It got me questioning the need for shiplaps over a robust rain screen. For that matter, aesthetics aside, is there an advantage in terms of drying, fire or woodpecker attraction/repulsion that planing it out of a rough sawn condition provides?
Finally, the boards are dry and will be installed in June/July during New England’s often humid summer. I am planning on shooting it with a 15 gauge and installing it tight. Is this wise?
Thanks, Stephen
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Hi Stephen,
I’m in Nova Scotia and have recently put up a reverse board and batten siding for our place.
I know you plan on installing it horizontally, but here’s a description of what we did in case you find it helpful.
We put a layer of diagonal strapping for our rain screen, followed by vertical strapping and then 6” wide boards.
We liked the idea of having more air space behind, but we have friends who did the reverse board and batten just with the vertical strapping behind.
We spaced our gaps the width of carpenters pencils and put bug screen at the bottom and around window openings. And beveled at 15 degrees the edges of cuts to shed water.
The advantage of the vertical installation was that we could grow or shrink the boards if needed by either cutting them on the table saw or adjusting the gaps by 1/16th increments to end up with decent sizes at corners and notches for windows.
Our friends had told us that they had spent a considerable amount of time worrying about keeping the gaps consistent only to find out a year later, that the rough boards had moved. Some swelling, some shrinking. And over the years, they’ve had to go and plug the odd knots that fell.
We used Stainless Steel ring shanked coil nails for our boards (for a siding nailer) and galvanized ring shanked nails (with our framing nail gun) for the battens.
The stainless steel nails were quite expensive so we only used them on the last layer and already had galvanized nails leftover from a job. We made sure we were shooting into studs with our diagonal rain screen because of the weight of the following layers.
I can’t speak to installing it horizontally with no ship lap. Personally, if it was my place, i worry that the air-dried wood would shrink on the south side and you would see your building paper behind.
It wasn’t the first time we were installing that kind of siding. Local mills sells boards where one side is planned and the other rough.
…
I’ve milled last year a lot of T+G boards from rough sawn spruce with a router and a table saw. After joining and planning all the edges for a diagonal solid wood subfloor. I don’t want to know how many passes it took.
The whole thing took 2 weeks of work and I definitely regretted not paying a local shop to run it through their machines to make the profile in one pass with their shaper.
Some shops don’t mill anything above 14 percent moisture content through their machines.
I personally found using a plunge router very helpful for the job. It beats having to set up featherboards on the table saw and you could probably get away without having to join the edge with a jointer that way. It will just ride along the board.
You’ll have to do it in a few passes per board or you’ll kill your router when the bit gets dull. Ask me how I know…
Sorry for this huge message! This question sounded very familiar to what I do!
-Jeanne
With horizontal siding, wether it’s clapboard, shingles, ship lap, etc the goal is to shed water away from the building.
Without an overlap, you’re setting yourself for leaks at every board and an easy path for bugs. On top of risking of staring at your building paper on the south side in summer. Wide wood siding will move with the seasons.
One thing i forgot to mention is that we oriented the growth rings so the boards edges would cup towards the building, not pulling away when they dried.
Look into it if you’re curious. It’s something old timers would do. And the wider the boards, unless they’re quarter sawn, the more you’ll notice it.
Hi Jeanne, Thanks for your generous description of your approach and the thoughts on the details. The diagonal strapping method is interesting. I guess my choice is between an extra layer of strapping (diagonal plus batten) and cutting the shiplap (with a table router, as you suggest). My board length however (18 foot) works perfectly for horizontal siding (36x28' structure) and is the look that I am going for. I loved the advice on placing the boards so that the edges cup towards the house. Eight inch boards are wide. Not sure how much cupping to expect on the south side but perhaps I can hand nail the edges on that side with stainless ringshanks. They hold pretty good.
I also recently read about doing shiplap on a table saw with a dado set up that would allow it to be cut in one pass instead of two.
Shiplap has horizontal surfaces the won't shed water. If you must do horizontal, I would try an in-between clap board where you only take off enough of the top edge so it sits somewhat flat, say a single pass over a 12" table saw at a low angle.
About 10 years ago I did a fence section where part was PT the rest was plain untreated pine. The pine has definitely grayed more but it is holding up surprising well when fully exposed to the elements.
For a house you want the color to be somewhat even, there are products out there that will help it pre weather to a more even gray color.
Hi Akos,
You wrote:
Shiplap has horizontal surfaces the won't shed water.
By this, do you mean that as water travels down the face of the board it will wick into the shiplap seam? I figure with a 3/4 or one inch shiplap overlap, the water would simply continue down to the outside of the next board. Am i missing something??
Shiplap has horizontal surfaces the won't shed water.
If you are cutting it with a dado, it won't have the bevel on the top. As the boards shrink over time, you'll get a gap there and the bottom of the gap will be horizontal which will collect crud and water.
What Akos said. Water tends to stick to the horizontal surface and it attracts mold and debris. I have had boards custom-milled with a 15° bevel at the lap, and an intentional 1/8" gap, which worked well.
yup, i get that, thanks for the description.
You wrote: "If you must do horizontal, I would try an in-between clap board where you only take off enough of the top edge so it sits somewhat flat, say a single pass over a 12" table saw at a low angle."
so, does this describe a treatment that is in between ship lap and a clapboard? So that the very top of the board has, say a 45 degree bevel on it that would fit under the drooping edge of the shiplap that sits above it?
More like a 5deg bevel, say 4" tall, no cuts on the other side. This makes it almost into bevel siding without taking so much material off. Since the cut is on the back side of the board, saw marks won't matter.
That is the stain I was thinking of.
also, I found this:
https://valhalco.com/where-to-use-lifetime-wood-stain.php
looks like the perfect stuff...
Thanks Akos. Will get the table saw out today and experiment.
You can install the boards in a clapboard-like fashion, you just need trim details that are not typical in Maine.
You can also install the boards on the flat without a shiplap; open-joint cladding works just fine when detailed properly. With a rot-prone wood like red spruce, I would bevel all of the board edges 10-15° and install them tightly together over vertical cedar or pressure treated furring, over a UV-stable, solid black WRB. There is some risk of pests but it's much lower than many people think. Use metal insect screening at the bottom. Venting at the top is less important than usual because the gaps that will develop between each board provide air flow.
Square peg in a round hole.
If you don’t want a lot of labor into milling, install the boards vertically- board on board would be a good fit.
Thanks for the feedback. Seriously considering reverse board and batten at this point, :)