[Andy Graves]

Did an overhang support with 1/2″ x 1″ square tubing. Went to the metal supply and had four pieces cut to length. Painted with Rustoleum and glued in place with construction adhesive.

Clamped the ends and made sure the metal was flush with the top of the plywood. Let is cure for a full day.

After installation with the counter siliconed to the plywood subtop it turned out amazingly strong.

Highly recommended if you want overhang support without corbels.

On the negative side, there is solid subtop under solid surface. This customer did not want holes cut but it would be advisable to cut some holes in the subtop over the cabinet sections.

[David Gerard]

I thought solid substrate was a no no?
Sure looks strong. We just use 1×1 steel and make 1×1 wood strips to trim out in between the steel tubes over the out side wall/bar face of the cabinets. Ply substrate strips in front and on the sides to screw tops down.
Did this job require a finished bottom like that?

[Andy Graves]

That is what the general contractor wanted.

We would typically cut holes in the subtop but didn’t on this one.

In my house I have a solid MDF subtop with no holes. It have been there for over five years without an issue. We do not use hot appliances over that section.

[KCWOOD]

Me too Andy. I have. 1″ MDF  , adhered and floats on dabs of silicone. Looks great coming up basement steps,

[Tom M]

We use 3/4″ x 1 1/2″ square stock often. Sometimes we will weld it to lattice around island/peninsula cook tops or slide ins.
3/16″ luan makes a nice finished cover and the overhang is automatically vented.

[Andy Graves]

So you put down the luan first and then just glue the metal channel to the luan?

Just out of curiosity, if I cut channels ever half inch and a quarter inch deep, would that act as a vent?

[Wayne]

We use 3/4″ X 3/4″ tube steel siliconed to the underside of the countertop where it’s needed, then dado out 15/16″ MDF (BTW…we use water resistant MDF) to cover the steel and finish the cantilever underside. We buy our tube steel in 20′ lengths, then cut it to length as we need.

[Wayne]

We use 3/4″ X 3/4″ tube steel siliconed to the underside of the countertop where it’s needed, then dado out 15/16″ MDF (BTW…we use water resistant MDF) to cover the steel and finish the cantilever underside. We buy our tube steel in 20′ lengths, then cut it to length as we need.

[Tom M]

The luan goes under the steel. It is there just to hide the steel. Venting becomes a non issue at that point. We take the “no solid substrate” rule very seriously.

It fills in the space left from the 12mm solid surface and the 3/4″ square stock (tube steel).

Same as Wayne, we buy it in 20′ lengths and cut it.

[Fab Man]

29 years of fab work with solid MDF under tops that had a overhang and not one failure. And we did plenty of tops during those years. While I understood the reasoning behind the thought of air/temp transfer I firmly believe it was overthought. Provide enough heat to the top and it will crack no matter how you make your supports.

[Steve , NY]

To a certain extent I agree with you Fabman, BUT ” he who pays the warranty picks the rules.”

[Tom M]

Yeah, Steve put it well.

We were one of the first warranty agents in ’88 when this whole thing started. I agree with Fab Man that there is little risk in his method. Truth be told, I made a lot of repairs that could have gone for or against warranty. I figured that the customer should get the benefit of the doubt in all but the most obvious cases.

I also noted that there was never one fab violation that caused problems. Always two or more. Seam over a dishwasher PLUS no seam block, for instance. The material really is fantastic in this regard.

[Seth Emery]

We used to use 1″x2″ tube steel, but now we use 3/4″x1-1/2″ tube steel – like Tom. We are using 7/8″ or 15/16″ MDF though. The 1″x2″ is slightly thicker than 2 Corian build-ups glued together (ever since they started making it a standard 12mm), so that doesn’t wotk too well for us. I like the 3/4″x1-1/2″ since you can dado for it and conceal it above the MDF subtop. This way, the MDF is in less pieces and is easier to install too. Occasionally, we’ll use 1/2″x2″ bar steel when the span isn’t too big. We don’t see a lot of need for steel support in residential work, but we do use it frequently in commercial work to support tops where there are large spans between the millwork company’s brackets.

[Andy Graves]

I used only 1″ wide. It sounds like you are using something wider. Do you notice a huge difference going up to 1 1/2″ wide?

[Tom M]

We always used the 1 1/2″, but I am pretty sure you get a substantial increase in support for a small increase in price.

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