If it were me I'd feel a lot better leaning on that counter if it had brackets supporting it.

(glad you got the cat in there: kitchens are better with cats)

As is, you could add brackets underneath. The better way would be to take the top off, and add hidden brackets, which are basically very thick metal straps that are anchored to the cabinets. The problem with regular brackets is that you bang your knees on them. Our maple top has a 15" overhang, and they have been working well. https://originalgranitebracket.com/products/hidden-island-support-bracket

Remove the top and clamp it to flat. Rout (6) 1/4" x 3/4" deep slots in the bottom, and fill them with epoxy and 1/8" x 34" stainless steel "rods". Overfill the slots and belt sand them to flush. Install corbels or 1" square tube to support the overhang and reinstall the top.

Joseph Corlett, LLC

How does that 1" square tube work? I'm trying to visualize it, but it escapes me.

So, StarCraft Custom Builders and Joseph Corlett, LLC would you say it's vital to install brackets? Or just for some added piece of mind?

Centerline Brackets also makes various suitable hidden supports. I used them successfully for my granite island 18" overhang. Outstanding customer service, they'll figure out exactly what you need. Visit their main website for more choices.

"How does that square tube work?"

19th post down.

First thing I'd check is whether the underside has been finished. It has to be finished with at least a good coat.

Even though this guy disagrees.Finishing the bottom He's just wrong for a flat board top.

Next check the grain orientation(curve of the rings) of each board. Each should be reversed from the one next to it. It looks like your boards are all the same with the rings curved up. This is the problem.

dan1888:

You don't get to just say "He's just wrong for a flat board top", you have to substantiate your position. Please do so. Thanks.

In my experience all the way back to my Lamello biscuit cutter and lots of clamped up board feet, he is wrong. But the main problem with the OP's top is the grain orientation of the boards. You reverse the grain every other board to help offset the expansion and contraction. That is part but not all. Some finish on the underside helps equalize the rate of expansion and contraction. His article is about completely stopping it anyway.

I agree a top built like that is doomed to fail, if your definition of failure is uncontrolled movement. Bolting/gluing a steel framework underneath it could have deterred it from moving at the risk of increasing to 90% the likelihood that it will split.

How do you build a successful (IOW, stable) wood top? You select narrow strips of dry quartersawn (vertical) grain and glue them up, not tree-width slabs of plain-sawn lumber.

The droopy side is because of gravity pulling it down, plus the fact than an un(der)finished underside is losing moisture while the highly-finished topside ain't.

If the OP decides to move ahead with some kind of reinforcement underneath, I can offer these tips:

Place a humidifier under the ledge for a few hours and see if the warp begins to level out. "Clamping it flat" isn't going to come without a price, it could split then and there, and the stresses will still be present, Tempering the wood to release stress is the way to go.

Steel tubing frame underneath is fine; it would allow "kerfing" with a saw every 3" or so along the grain (stopping short of the end-grain so it stays invisible). Kerfing with a circular saw reduces the effective thickness of the slab to whatever margin of uncut material is left. I would leave 5/8". The steel tubing frame gives it structure. The screw holes in the steel frame will need to be slotted out at the edges so the wood can expand and contract (a center row of holes can be left normal, as this will center the frame to the wood, ensure that movement occurs evenly-distributed across the width.

Casey

Joseph Corlett, LLC

"How does that square tube work?"

19th post down.

That is pretty slick. We usually just use flat steel or an "L" bar (kerf it into the top with a saw blade). What is the advantage of a square tube?

I don't see why a ton of cure is needed for a two pound problem.

Take a straight-line saw and cut off the drooping edge. Re-cut the removed piece on the table saw to square up the board, then reattach with some yellow glue and clamps. This should straighten out most if not all of the droop which appears to be localized. If the bottom is usable, I might flip it over before reattaching it. It might need a little sanding to smooth it out.

No need to remove the top which might be a messy process depending on how it is attached.

If brackets are not wanted, then drill and countersink for 14-16" lag screws 1/2" or 3/4" diameter and install 4 or 5. Plug and sand the holes and sand and refinish the top. All done. Not fancy, but it works, it's easy and it's cheap. Less than $40.00 for the whole caboodle.

@ Capecodder

So, StarCraft Custom Builders and Joseph Corlett, LLC would you say it's
vital to install brackets? Or just for some added piece of mind?

Some sort of support should would be a good idea. If you don't want brackets for reasons given here or other reasons, the method described above will work to support the edge. However, just because you have a 10" overhang does not mean 10" brackets. 6" brackets will leave a 4" unsupported overhang (which I defy even Shaquille O'Neal to bend), and poses little risk to errant knees.

"What is the advantage of a square tube?"

Steel on the flat isn't very stiff, even 1/4", and most who use it disregard the 1/3-2/3 cantilevering rule.