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Joining slabs for a countertop

Iamjoe's picture

Hi all - I would like to make a wood countertop for my craftsman style kitchen island.  It will be about 10 feet long by 5 feet deep, with about 1 1/2 feet of that depth an overhang for sitting at.  I would like to join 12" wide quartersawn white oak planks for this.  Can you give me any ideas on the best way to join the planks, particularly so that they are all flush on the surface (obviously can't run it through my planer)?  How thick should the planks be?  Is there a better wood that will be more resistant to warping, yet still mesh with the craftsman cabinetry?  Any advice is appreciated, including telling me if I am crazy to try this!

BoardmanWI's picture

(post #106767, reply #1 of 9)

It's not a crazy idea and 12" white oak should look nice. Personally, I'd join them with pocket screws/glue. You could clamp pieces flat on the surface and then screww them together.

MikeHennessy's picture

(post #106767, reply #2 of 9)

I did a cherry countertop almost that big. At the time, I was limited to 8' lenths of wood tho',  so I cut them into 2" X 2" strips and rejoined them into 12" wide sub-assemblies that were joined to make up the full width. That way, I could stagger the end grain joints and run them through the thickness planer. You wouldn't necessarily need to do that, but I think having the top built up from 2" sections adds to the stability of the wood. I also happen to like the "butcher block" look.

As for a flat top, I just used biscuits to align the joints so they were relatively even across the top. Cauls would work as well. Or dowels. Your choice. A belt sander finished off the job nicely. Thickness of countertops generally range from about 1-1/2" to 2", or more, thick.

If you have a sink or cooktop in this island, I'd rethink wood -- at least in the vicinity of same. Just my $.02, but IME, wooden counters do not mix well with sinks or stoves. Too much maintenance involved if the wood is constantly wet and/or hot. Swelling, warping, rot, mold. You get the picture.

Still, some advocate epoxy finishes to reduce the water problem. Me, I prefer the look of an oiled countertop, well used -- even mildly abused (we mix dough, cut, pound, eat on, and generally treat ours like a workbench as opposed to a piece of furniture) -- so epoxy just doesn't do it for me.

Joining edge grain should be fine, even if you don't use biscuits, etc. Use something like Titebond III or Gorilla glue.



Mike Hennessy
Pittsburgh, PA
Everything fits, until you put glue on it.

Mike Hennessy
Pittsburgh, PA
Everything fits, until you put glue on it.

mike4244's picture

(post #106767, reply #3 of 9)

I would be wary of cupping with wide boards. You could rip the boards into 6" rips and alternate the grain so cupping would be minimal. No matter what you do you will have a lot of hand finishing with a five foot width. One inch thick boards. I would use battens underneath also. Make sure you allow for wood movement,they'll be plenty in five feet.Bread board ends that allows the boards to move.The choice of wood is fine.


Iamjoe's picture

(post #106767, reply #4 of 9)

GREAT idea on the breadboard ends, Mike. Glad I asked. I will probably go with 6" planks as well, but what do you mean by "alternating the grain"? Don't you think that a 2" thick top would be less prone to warping? And as far as battens, I'm thinking that the countertop cleats would serve the same purpose?

saschafer's picture

(post #106767, reply #5 of 9)

Thick planks are actually more prone to warping (and cracking) than thin ones, because they have more built-in stress.

If your planks are truly quartersawn, with the growth rings almost perfectly perpendicular to the surfaces, you'll have minimal warping, but the more they deviate from perpendicular, the more movement you can expect.



mike4244's picture

(post #106767, reply #7 of 9)

Battens and countertop cleats,same thing.Make sure the fastner holes allow for movement, you will get a lot in five feet.If you look at the ends of plain sawn boards toy will see a series of arcs that make up the grain. If you rip the board in half and put them side by side with one arc convex and the other concave,that is what I meant by alternating the grain. When you ripped the board the arcs all went the same way.

This does not eliminate cupping, but minimizes it. If you can get all quarter sawn stock, then this does not apply.

Two inches thick would be excellent.You will need help in the shop with a top that heavy. 5x10=50 sf =100bf.I am not sure what white oak kiln dried weighs per foot but I do know the top will be a bear to move around.


Edited 6/17/2009 7:18 pm ET by mike4244

KeithNewton's picture

(post #106767, reply #6 of 9)

Hey Joe. First, I think you are going too wide at 5'. If this is going to be at bar-height, a foot of overhang is enough for the knees and feet, so I don't know what is required on the cabinet side of that.

When I do wide tops that I want to control the flatness of, I like to clamp them together dry, then route T slots into the underside, then oil and wax the members which are in the T-slot at the time of glue-up. The glue and wax keeps them from getting glued in, and provides structural support for connecting to the cabinet, and supporting the overhang.

You can work that into the architectural details underneath if you want to hide it.

If you are using QS of any wood, you don't need to worry about cupping as someone earlier suggested. UNLESS your QS boards get close to the heart, and the rings are > than ~45º to the face. It is the tight arcs of the rings near the pith which cup and change the greatest.

John P's picture

(post #106767, reply #8 of 9)


I've made a couple of wood island tops of somewhat smaller size and used two rows of large biscuits and lots of glue to join the planks. Then hand plane the slightly uneven joints further and finally sand the top. I would reconsider the wood species unless you plan to finish with poly to prevent water penetration which will stain oak. The traditional woods used are teak and maple if you only plan to oil it with something like butcher-block oil. Ipe also works well. This project is very labor intensive and you will have a piece of wood weighing 300+ pounds!! Lets you know who your friends are when you go to move it to the cabinet base-which by the way needs to be substatial. Good luck!!

onthelevel1's picture

(post #106767, reply #9 of 9)

I just assembled a table top 70" long x 30" wide.  I put together 3 10" pieces which I was able to plane.  Next step was to assemble the 3 pieces using the WoodRiver clamps (now on sale at Woodcraft for $20).  They helped ensure flatness across the width & are expandable to any width based on the length of 2 x2 you choose to use.  Next week it goes to the sander shop to get it really flat.

While 30" isn't 60", any assembly process you choose can be helped by these clamps.  For a 10' long counter I would suggest 6 clamps suplemented by additional pipe or bar clamps.