Walnut Counter Top Thickness?

[julian abram]

I would like to build a Walnut top for our kitchen island later this summer. This island does have an electric cook top but not sink. I've began to start thinking about purchasing some rough sawn stock for this project. I'm wondering what would be the best final thickness for this top. I'm guessing somewhere between 5/4-8/4. The finished top dimensions will be approximately ?x42"x84". I would like to construct the top from some boards about 6"x8'. What thickness would you suggest?

[jack duren]

You will usually get 8/4 at 1 7/8 and will generally finish at 1 3/4. Counter tops are usually 1.5 but I would try and get 1 .75 out of the walnut...

[Leo Graywacz]

Stone countertops are 3cm around here. I'd shoot for something around there, 1 1/4".

[Von Bickley]

My granite counter tops are 1-1/4".

[jack duren]

What does Granite have to do with solid walnut?

[Prashun Patel]

As long as the cooktop has no issues with the thickness I don't see an issue leaving the top whatever thickness you wish.

How are you planning to finish?

[David Utterback]

For aesthetic purposes, the comparison with other materials seems appropriate. Thickness is somewhat dependent on the amount of overhang and the support structure but 1 1/2" should be sufficient in typical designs. You may also want to think through the finish since some heating is likely and grease spatters may be frequent (at least they are at our house).

Please keep us informed on your progress.

[glenn bradley]

What does Granite have to do with solid walnut?


My assumption is a reference to the visual aesthetics. Recommended thickness versus what we are used to seeing as a 'counter top'.

Depending on the use, full thickness may or may not be the way to go. For me, walnut would be too soft to use as something like an 1/8" veneer on a substrate. Thicker than that and you have to address seasonal movement as in any other glued up panel. My point is that 7/8" material that is well supported with an edge joint to present a thicker slab could be viable. A solid slab would be my preference but, I'm just offering some food for thought.

[julian abram]

Finish is a good question, we kinda know the finished look wanted but haven't exactly planned the steps to accomplish it. We would like some variation in color, so I'm not planning to cut out or dye the sap wood. Of course it depends on the lumber I purchase but thinking maybe 20% sapwood mixed in would provide some nice contrast. Obviously some type of clear finish that would resist grease splatters and water spots. Suggestions for finishing materials and procedures are welcome.

[jack duren]

My assumption is a reference to the visual aesthetics. Recommended thickness versus what we are used to seeing as a 'counter top'.

Depending on the use, full thickness may or may not be the way to go. For me, walnut would be too soft to use as something like an 1/8" veneer on a substrate. Thicker than that and you have to address seasonal movement as in any other glued up panel. My point is that 7/8" material that is well supported with an edge joint to present a thicker slab could be viable. A solid slab would be my preference but, I'm just offering some food for thought.

I can tell you this and will say no more. Our business is solid tops. We do not go thinner than 1.75 because of stability. You can make them the way you want but we learn from experience not from aesthetics. Your call,but not mine....

[glenn bradley]

I can tell you this and will say no more. Our business is solid tops. We do not go thinner than 1.75 because of stability. You can make them the way you want but we learn from experience not from aesthetics. Your call,but not mine....


Jack, this is excellent information. Solid wood, right? Nothing better than hearing from someone who actually has experience in doing a lot of what a question is about.

[Sam Murdoch]

Solid Tops? What kind of solid - wood? corian? granite? butcher blocks?

LEO - from post # 3 above is in the very high end professional cabinet making business and I'm guessing that he and I have seen or installed more than enough solid wood or other c-tops to be able to offer "solid" advice. His 1-1/4" reference is a very good start - maybe you can go to 1-1/2" but anything thicker than that starts to look overbuilt. How many table tops have you seen thicker than 1-1/2"?

An island top that is supported by cabinets below and possibly some posts and corbel details, if there is a span remaining open for seating, is typically more than adequately supported for any purpose. Stone tops are more likely to break from being improperly supported. A wooden top in the 1-1/4" range will be strong and dimensionally stable. An 1-3/4" thick wood top that is set up as a butcher block top makes sense but would likely require some rework at the cooktop cut out. Using a plain sawn board top, with the grain orientation in the width of the boards, the extra thickness adds no function other than perhaps to be esthetically pleasing.

If your top will span across an open seating area and you are concerned about deflection it is easy enough to build up the edge just under that section. A piece of 3/4" ply set back from the edge 3" so as to be practically invisible (perhaps with a strip of finished solid wood to conceal plywood edges visible from any other seating in the room) is more than enough and a typical solution.

Still, having said all that, to quote Prashun - "As long as the cooktop has no issues with the thickness I don't see an issue leaving the top whatever thickness you wish."


Edit - I have built a 3" thick walnut island top and some in the 2"+ range, one of English Elm and another 2 in cherry, but these were tops without appliances (read your appliance install specs) and were customized along with other details in these kitchens that visually complimented the EXTRA thickness of these unique tops. The walnut top was actually built up to that thickness and not all from 3" + thick boards. So - yes, anything is possible and acceptable with context and full awareness of the implications. That's the beauty of woodworking.

[Wayne Lomman]

As another professional, I agree that 32-38mm is the ideal for all the reasons above.

Finish it with 2 pack polyurethane. It looks great and it works. Anything less will not stand the test of time in my experience. But don't over build it. Apply just enough coats to get the look and that's it. More isn't necessarily better. Apply the one product only in 2 or 3 coats. No sealers or primers or fillers, just the polyurethane. Cheers

[Scott T Smith]

Julian, I too would suggest a finished thickness of 1-3/4", and no less than 1-1/2". Kitchens tend to be humid so I would also suggest finishing all sides of the countertop with the same number of coats of finish, so as to resist cupping over time.

Additionally I would encourage you to source either single width slabs to make your counters from, or bookmatched narrower slabs that would allow for a single seam.

unlike Wayne I am not a big fan of poly on furniture. A post catalyzed conversion varnish is very water and chemical resistant and would be my first choice unless a glossy appearance was desired. If glossy finish us desired epoxy is the way to go.

[julian abram]

Scott, thanks for the good suggestions. Like your suggestion and others on thickness, I have decided to start with 2" rough sawn stock and go from there. On the finish, we would prefer just a clear matte. There is a lot of walnut milled across N. Arkansas/S. Missouri, I need to start checking some sources and see what size stock is available. thanks.

[Christopher Hedges]

Something to consider might be using 4/4 material and building up the edge to whatever thickness you want. Add support underneath where needed.

[Wayne Lomman]

Julian, I too would suggest a finished thickness of 1-3/4", and no less than 1-1/2". Kitchens tend to be humid so I would also suggest finishing all sides of the countertop with the same number of coats of finish, so as to resist cupping over time.

Additionally I would encourage you to source either single width slabs to make your counters from, or bookmatched narrower slabs that would allow for a single seam.

unlike Wayne I am not a big fan of poly on furniture. A post catalyzed conversion varnish is very water and chemical resistant and would be my first choice unless a glossy appearance was desired. If glossy finish us desired epoxy is the way to go.

Just to clarify, the 2 pack polyurethane I refer to is a specific type of post catalyzed conversion varnish among the many classes of 'varnish available. I avoid using terms like 'varnish' as they are so broad and non-specific as to not convey any accurate information.

For bench tops, polyurethane is an excellent performer. It is available in any gloss level and is highly durable as it is both physically tough and chemical and water resistant.

Cheers