Need help with a large island design

Looking to make an island top that is large. 60" x 100". It will have a 36" overhang on one side, and be supported by 2-3 legs.

My questions are:

1. Would a thicker top make more sense due to the size? 1.5" vs 3/4"

What about using 1.5" breadboard ends, and a side pieces that are 1.5" thick while keeping the rest of the island 3/4"?

2. Another idea was to put a trim piece around it to make it appear thicker? I am afraid that wood movement would make this impossible.

Thanks for the help brainstorming

What about using veneer to a plywood substrate?

Would I be able to align the veneer as to not see the seems? Would the seems be visible at different times of the year?

How thin could I make the veneer in order to prevent wood movement so i could use use a 2" trim piece all the way around?

That's just a little bigger than the "monster" I built for a client/friend earlier this year...which was 52" x 81". My material was finished thickness at about an inch and 5/8 if I recall. No way would I make a large surface like that with only 3/4" or even 1" material, even if the regular counters in the area were that thin. I personally like the heft of a good, solid surface. I'm actually in process of quoting on a 30" x 102" x 1.5" black walnut surface for a similar purpose.

If you like the look of breadboard ends, your idea with thinner boards in the field could be made to work, but you'll need to be creative relative to securing the breadboard ends since you obviously will not have thick material to groove in the middle where you typically have your fixed pin. For the latter idea, even if you can deal with wood movement, you'll have the issue of the trim being essentially what looks like a very narrow breadboard end where it masks the end grain of the boards in the field. Will you like that look?

Thick veneer over plywood (not veneer plywood which would not hold up) would help with the wood movement issue, but you'll still have to like the look of the trim.

I think it's largely an appearance thing. What you describe is essentially a table. Tables normally have tops less than an inch thick. But they also have aprons that help keep them flat and help with deflection. A 3/4 top with an apron might be another way to go, it could also help with leg attachment. Or a thick top - but that may not stay flat and if a piece of hardwood 1.5 inches thick wants to warp, it is going to warp.

A 36 inch overhang is huge. It is going to need legs. But you can also get steel pieces you can attach to the cabinets to help support it on the other side and take some of the weight. They are sold to support granite counter tops. I used them to support a 15 inch overhang (in a granite top).

I wouldn't go thinner than 1 1/4" personally, given the over hang, at 3/4" thats going to want to curl and warp. You don't need bread board ends on a thick top, but you could use them if its a look you like, just build for the wood movement. Thats a pretty large top to veneer, do you have a bag that big? You could veneer narrower sections and glue this up to width, but that wouldn't be my first choice. You can make a thicker edge by gluing up long, track saw off a few inches, fold this under itself and glue it on...no movement issues because the movement is in the right direction, then you just have to add a long edge which can also be ripped off each edge of the top if you glue up wide, then all the color/grain match is pretty good, I've done this to get a look like 3 1/2" when material that thick wasn't cost effective.

I'd go 6/4 minimum and that's only If you have relatively flat rough stock. 1.312 to 1.5 finished would be where I would want to be.

I actually just picked up a pile of 6/4 sapele for a 96x60 island. It only has a 14" overhang with fully supported ends though.

This would be for a client. They are looking to use repurposed post from their front porch as the overhang legs.

No o do not have a bag big enough to veneer that.

If I don't use breadbord ends and decide on using 8/4 stock what or some tips on keeping it flat?

What wood are you thinking of using? Will the cut be flat sawn, quarter sawn, rift sawn?

Breadboard ends are an aesthetic choice, IMHO. If the boards are made with spring joints you don't need a breadboard.

I agree anything thinner than 6/4 shouldn't be used, especially with a 36" overhang. But the sheer size of the top may make even 6/4 look anemic.

What is the intended look of the top? Rustic, polished, raw?

As Julie says, breadboard ends are an aesthetic choice not a structural one. Bad aesthetics, mind you, but that is just my opinion.

Thickness needs to be 1 1/2 as a minimum. Anything less will look and feel under done and prone to instability. Use dry timber and straighten each piece individually so that it clamps together without stress. Alternate the orientation of the growth rings. Seal both sides when applying the finish. Use a decent quality glue. Cheers

Type of wood is yet to be decided on. The look is aimed towards rustic.

If you buy quality and consistent material, mill the stock correctly and glue it up carefully, "flat" shouldn't be an issue.