Making shiplap for a wall - kerf on back? And other questions, too.

[Brian W Evans]

I am taking on a project to mill and install shiplap ash on the walls and ceiling of a small home office. I watched some videos about this and a few recommended putting a couple of saw kerfs lengthwise on the back of each board to help minimize warping/twisting. What are your thoughts on this? If I do this, how deep should they be?

I will be using 4/4 KD ash that I will mill down to 3/4 - 7/8" from rough, depending on the quality of the material I get. Shiplap will be cut using a dado stack.

The space will be climate controlled and dry. The shiplap will be installed over drywall.

Other questions for you:

I plan to use a nail gun to shoot through the tongue(?) of the boards so there won't be visible nail holes. The owner wants to mount computer monitors and possibly a TV to the shiplap. It will be difficult to locate the studs through the shiplap and drywall, so they will probably expect the shiplap to hold everything up by itself. I don't feel that 16ga nails shot through 3/8" of ash and 1/2" of drywall will be strong enough for this. What are my best alternatives?

How do I extend outlet boxes, switch boxes, etc. out through the drywall and 3/4" of shiplap?

They are considering having me build a desk out of ash as well. I would like to have a very smooth, hard surface for the top. I will be finishing with target coatings em6000, probably with the crosslinker added. What is the best way to fill the grain?

TIA for any suggestions.

[Bill Dufour]

They make box extenders that simply screw onto the existing boxes. Or I have cut a deeper box on the bandsaw to be flush. No reason not to cut a full box and make 2-3 extenders from one box.
The extenders do not require the wiring to be touched.
Bill D
https://www.lowes.com/pd/ReceptXtenders-1-Gang-Blue-PVC-New-Work-Old-Work-Standard-Box-Extender-Wall-Electrical-Box/999978308

[Brian W Evans]

They make box extenders that simply screw onto the existing boxes. Or I have cut a deeper box on the bandsaw to be flush. No reason not to cut a full box and make 2-3 extenders from one box.
The extenders do not require the wiring to be touched.
Bill D
https://www.lowes.com/pd/ReceptXtenders-1-Gang-Blue-PVC-New-Work-Old-Work-Standard-Box-Extender-Wall-Electrical-Box/999978308

Thanks, Bill.

[Paul F Franklin]

If you know roughly where the monitors/TV will be, I'd cut out a section(s) of the sheetrock and install strips of plywood to provide solid backing for mounting the equipment. You can make them as wide and as long as needed to ensure good backing. While you're at it, you can install some feedthrough boxes to allow feeding power and signals to the equipment without having cables hanging down the walls.

[Wes Grass]

If you know roughly where the monitors/TV will be, I'd cut out a section(s) of the sheetrock and install strips of plywood to provide solid backing for mounting the equipment.

I like this ^

My gut feeling is small nails thru the tongue is going to result in it being a cosmetic panel at best.

I tried cedar shiplap in my bathroom. It was cupped and was going to be a nightmare to trim out. I kinda liked the look at first. I used stainless siding nails, and the small heads on them wouldn't hold it flat, they just sunk into the wood. Video's I've seen suggest using real nails with big heads, and get a 'Farmhouse' look from it.

I considered starting over, milling the wood myself, and using 16d galvanized nails. But decided to tear it out and drywall instead. Never thought of kerfing it on the back.

So there's an option, big exposed nails. And finding the studs shouldn't be too difficult. You can mark up, and even drive nails thru to verify, and all the 'damage' will be covered up.

[David Lageman]

Although I didn't mill it myself, I just put up a shiplap wall in my daughter's new condo. The premade version of kerfing was shallow channels on the back side, akin to what you might see on the back of a base molding. May not work on a "clients" house, but on her wall I used liquid nails and then caught the studs with a nail gun at the top of the tongue. The next board covers the nail so no holes visible when completed.

I used the plug extenders linked above but make sure you get the correct size for your material - they sell them in different thicknesses. They bring the plug out to the shiplap. Throw a new faceplate on it and it turned out great.

As to mounting, I would highly recommend what Paul suggested and install some backing and install a cable access and new outlet located behind the TV. It creates a much cleaner look with no visible wires. Although I think the wall I installed would likely hold a TV, because the of the glue/nail combo, I ended up using some heavy duty Toggler anchors to mount the TV bracket. Again, my client was my daughter so I was able to cheat a little but the correct way to do it would have been to install backer board, at least in my opinion.

[Richard Verwoest]

You could also draw a quick diagram of where the studs are located before adding the shiplap. Pencil, paper, stud finder and done.

[lowell holmes]

Why don`t you experiment using scrap wood to answer your question? I bet you can come up with it in an afternoon.

[Erik Loza]

The A&D company I did a stint with offered shiplap cladding as one of its product lines. As others have said, you definitely want to go through the studs, not the cladding. No way that cladding alone will hold any amount of weight. Many times, we had to explain stuff like this to the architect (vis-a-vis, the homeowner) since they just saw it on pinterest and the wife says, "I want it". My recollection is that ash can be pretty brittle. I always advised the architects to budget for 20%, if not 30% waste. Good luck with your project.

Erik

[Brian W Evans]

If you know roughly where the monitors/TV will be, I'd cut out a section(s) of the sheetrock and install strips of plywood to provide solid backing for mounting the equipment. You can make them as wide and as long as needed to ensure good backing. While you're at it, you can install some feedthrough boxes to allow feeding power and signals to the equipment without having cables hanging down the walls.

Thanks, Paul. I like this idea. The likely mounting areas are probably between 48" and 72" above the floor, so I can just put a strip of ply at that height all the way around. Easy. Maybe I'll even put some blocking behind the ply to really make it sturdy.

[Brian W Evans]

As to mounting, I would highly recommend what Paul suggested and install some backing and install a cable access and new outlet located behind the TV. It creates a much cleaner look with no visible wires.

Good advice, David. This is the plan already since the client wants a very clean look in this space. I will be running ethernet cable to a few locations in the room and the electrician will rough in the outlet and switch boxes in likely areas as well.

[Brian W Evans]

Why don`t you experiment using scrap wood to answer your question? I bet you can come up with it in an afternoon.

Always good advice, Lowell, but I'm asking here first because shiplap is not new and someone must have encountered similar issues before. I'm hoping to save some time and benefit from others' experience.

[Brian W Evans]

The A&D company I did a stint with offered shiplap cladding as one of its product lines. As others have said, you definitely want to go through the studs, not the cladding. No way that cladding alone will hold any amount of weight. Many times, we had to explain stuff like this to the architect (vis-a-vis, the homeowner) since they just saw it on pinterest and the wife says, "I want it". My recollection is that ash can be pretty brittle. I always advised the architects to budget for 20%, if not 30% waste. Good luck with your project.

Erik

Thanks, Erik. The studs are definitely my targets for the nails - I wouldn't depend on drywall to hold anything. I have worked with ash several times before and haven't had any trouble with brittleness. I'm in New England and I will be using white ash - maybe there's a different species down south?

[Brian W Evans]

My current thinking is that I will experiment with screws into the studs in a few places. I will counterbore the holes and cut plugs to hide the screws. This will make the shiplap extremely difficult to remove, but that's sort of the point.

I really can't do nails through the faces since the client wants a clear finish over bare wood and doesn't want to see nails or filler.

Any thoughts on the kerfs?

[Bradley Gray]

I would suggest making spline and groove instead of shiplap.Simpler to make and install. I have done several projects this way.

I would also suggest horizontal furring 32" OC screwed to the studs. Then screw the paneling to these strips.

Hang anything anywhere.

[Bob Cooper]

Are you doing a big section. You may want to cover that wall with plywood first and then cover that with shiplap. I just did some walls with Nickle gap for a similar use ans I like it better because the entire surface is flat. Let me see if I can find a couple pix. Well...seems hard to do from an iPhone so I’ll do this tomorrow

[Mel Fulks]

I think it needs to be vertical...not Lincoln Logs lateral. We usually made the stuff on a shaper . To make the face work well with a no gap fit
back was made to be open about a scant 1/16th. I prefer a bead front,with old type pointed bottoms ....not the bowling alley gutters.
And I think it always looks best painted ,and nailed with the 19th century type squarish flat head nails.

[Peter Kelly]

I don't feel that 16ga nails shot through 3/8" of ash and 1/2" of drywall will be strong enough for this. What are my best alternatives?2 1/2" 15ga finish nails. Which way are the boards going to be oriented?

[Brian W Evans]

Are you doing a big section. You may want to cover that wall with plywood first and then cover that with shiplap. I just did some walls with Nickle gap for a similar use ans I like it better because the entire surface is flat. Let me see if I can find a couple pix. Well...seems hard to do from an iPhone so I’ll do this tomorrow

This is basically the look we are going for. How did you attach the boards? Was there drywall under the plywood?

Is this shiplap, or just straight boards? If straight, did you do anything to the surface underneath to make it blend in?

[Brian W Evans]

2 1/2" 15ga finish nails. Which way are the boards going to be oriented?

Horizontal. Can't change that.

[Brian W Evans]

Here is an example of what the client wants - very clean, no nail holes.

459248

[Phillip Mitchell]

Brian,

I installed some horizontal Nickel Gap “shiplap” for a client in their walls a few years
back and can offer some of my experience. I actually used 1x8 MDF that was T&G and not an actual shiplap joint because I also didn’t want any visible nail holes or filler used. I prefinished the MDF off site spraying with a white pigmented lacquer so touching up after install was something I was avoiding.

If you think through the mechanics of the shiplap joint, you realize that there isn’t a good way to only blind nail the board enough to be secure and flat against the wall across its width (and avoid visible fasteners.)

Say you start at the bottom with the open side of the joint up - you can nail through it near the floor if there’s going to be some type of base trim to cover then nail through the open tongue that’s on the top side, but the next course you can only blind nail the top open tongue again and this leave the bottom edge of the 2nd board and after “floating” as it’s not captured by the joint itself and you don’t want to face nail it to pull it in.

Ok, now say you inverse it and start with the closed side of the shiplap joint facing up and you won’t really be able to blind nail anything as you go because you are capturing the open tongues behind the closed side. With a true shiplap joint, you will run into this problem whether you start from the floor and work up or from the top and work down. This is why you traditionally see it face nailed as well.

I chose to use a tongue and groove nickel gap that looks exactly the same as all the shiplap once installed, but has the mechanical advantage of a truly locked in joint along the T&G edge and nailed through the tongue on the “open” edge. I also used a decent amount of construction adhesive behind the boards as I went for extra peace of mind. This was installed over existing drywall. I would absolutely not rely on just the board cladding to support a TV or audio equipment and find studs for that. You will need to find them anyway for the cladding install so just keep notes for each wall as to where your centers are and you will be fine...or add strategic blocking ahead of time as several folks have suggested.

I cut around existing outlets/switches/etc and used longer screws to mount the covers back on with existing ones and simply installed new boxes in a few places where we added new electrical.

Here are some photos of what I did. It was a satisfying job overall, as I have some other woodworking scope (floating shelves, walnut accent wall, built in hinges benches, etc) aside from the nickel gap, but the white nickel gap does provide a pretty clean and bright look.

Ash is one of my favorites and I feel like it could be absolutely beautiful with some carefully selected stock with clear grain.

[Brian W Evans]

Thanks, Phillip. Your point about the T&G makes a lot of sense. This won't take much more time than cutting shiplap but will definitely be more secure and less prone to warping. I don't know why but I hadn't thought of a square profile T&G before.

Nice work, BTW.

[Mel Fulks]

. To make the face work well with a no gap fit
back was made to be open about a scant 1/16th.
Did that by adjusting , the fence, so that cutters could remove right amount, then putting feeder on high speed and using climb cut

[johnny means]

Are you doing a big section. You may want to cover that wall with plywood first and then cover that with shiplap. I just did some walls with Nickle gap for a similar use ans I like it better because the entire surface is flat. Let me see if I can find a couple pix. Well...seems hard to do from an iPhone so I’ll do this tomorrow

This. OSB is cheap and will prevent any future issues with mounting/ hanging fixtures.

[Brian W Evans]

This. OSB is cheap and will prevent any future issues with mounting/ hanging fixtures.

Yeah, it USED to be cheap. Right now it's $52 for 1 sheet of 1/2" OSB. Cheaper to use 1/2" ply at $47.

Fortunately it's not a very big space, but it will still add a few hundred to the materials cost.

Drywall -> ply -> ash t&g (or spline & groove) is going to be my plan.

[Brian W Evans]

Still no opinions about saw kerfs or relief cuts on the backs of the boards?

[Mel Fulks]

I have never seen the need for routine kerfs. If some of the stuff gets gets too curled up before install, then kerfs can help.

[andrew whicker]

When you put the construction glue on, do you spread out with a spatula before attaching to the wall?

[Mel Fulks]

I just put a number of blobs .

[David Lageman]

I just put a number of blobs .

+1...my method as well.

[Bob Cooper]

Brian

I did a whole bunch of this in my basement and I’ll shoot some pictures. One is above. But originally I ordered it milled and the milled wood does have relief cuts. But then I ran out and had some rough stock that I milled without and I didn’t notice any difference. Also I made the T&G two different ways — originally on the router table and then later on the table saw. Both worked ok

i didn’t have issues hiding the nails. I installed with the mortise pointing down. You do though need to be careful when you nail through the tongue at the top that you do not obstruct the space behind where the next board rests.

also I just drew a line over every stud and put 1 16 gauge nail per every stud.

I just ordered some more and went ahead and ordered it milled vs me mill it. Just saved a lot of time and labor.

BTW all mine is cypress

[Steve Rozmiarek]

Thank you pinterest for giving us a shiplap shortage. Seriously, I had some on order for a month, finally gave up and made it. I would use a shaper instead of the dado because you want a flat cut. I do not back cut it, if your stock is stabil, it gains nothing. Don't overthink it, a 15g nail on an angle is tremendously strong. We do a lot of this, never with plywood backer. Two reasons, first it's unnecessary, second it breaks the fire wall. If you just put plywood to the studs, you have to drywall over it anyhow by code. You gain nothing by adding a sheet of plywood under drywall except in the rare occurrence that they may hang something heavy on it. People do these walls to show them off, not hang junk on, so don't over think it. It's not hard to hang a TV mount in a stud. You don't need to though, shiplap nailed up will hold my 260 pounds. I've tested. Glue it to the drywall if it worries you.

[Bob Cooper]

Brian:

here's a few more pictures. i took a couple of the milled wood that i received and also the spec for how they machined it (and pricing in case it helps).

459476459477459478

[Erik Loza]

Thanks, Erik. The studs are definitely my targets for the nails - I wouldn't depend on drywall to hold anything. I have worked with ash several times before and haven't had any trouble with brittleness. I'm in New England and I will be using white ash - maybe there's a different species down south?

Brian, I owe you an apology. The ash I was remembering was one of the heat modified ones like Thermory or some such brand: Much more brittle than just regular KD stuff. It sounds like you have a solid plan in place for the process. Please share pics when it’s done.

E.