[toolbelt Tina]

I am tiling my counter top that measures 40.5 x 94 inches. I am using 23.25" and a 17.5 tile. The overhang is 16" beyond the cabinet.The tile is thicker than the normal 12x12s. It is a porcelain tile. I put down 3/4 plywood and 1/4 hardiboard. The overhang part sags a bit. Should I sandwich
some 1x2 in between the hardi and ply to give it more strength or support with a L bracket? Or is there a better plan?

 

[Just Bill]

Overhangs need proper support, either in the material making up the overhang, or with knee braces. For the support to be strong enough it has to go back over the CT, just adding to the existing will not work, for long.

 

[ccarlisle]

Since the cbu doesn't add any dimensional strength, in essence you have 3/4" plywood. It'll need more support and if that support is to come from the top itself, you'll need more plywood.

 

[toolbelt Tina]

Since the cbu doesn't add any dimensional strength, in essence you have 3/4" plywood. It'll need more support and if that support is to come from the top itself, you'll need more plywood.

I knew I could count on my tiling experts:thumbup: thanks guys

should I add another 3/4 sheet or would adding a smaller thickness do?
What about my idea to strengthen by sandwiching some 1x2s?

 

[ccarlisle]

We do tile countertops with overhangs (more like islands) where the thickness is based on a solid-looking structure, using various thicknesses of plywood sheets, Ditra and tile, to a maximum in overall thickess of 2 1/4". This allows us to use Schluter's RONDEC-STEP edging which gives us a clean, popular 'look'. We don't use cbu all that much as Ditra does the job quicker and better and gives us a waterproof surface. Other thicknesses are OK but with big tiles, I'd want to see good support.

A sheet gives fuller support than strips or L brackets. What thickness have you to work with?

 

[toolbelt Tina]

many thanks

We do tile countertops with overhangs (more like islands) where the thickness is based on a solid-looking structure, using various thicknesses of plywood sheets, Ditra and tile, to a maximum in overall thickess of 2 1/4".

I am also building an island/counter hence the 16" overhang for stools.
I had not put much thought into overall thickness. I had some high end molding given to me which would have equalled the ply, hardi, thinset and tile.

A sheet gives fuller support than strips or L brackets. What thickness have you to work with?

I had seen where they put in the strips in between on the perimeter and a X on the inside.

I'll build up the overall surface to the 2 1/4 you advised. Now given that I am working with two different sizes 23.25 and 17. Should I put the larger tile on the overhang so It straddles more of the solid surface of the cabinet? Or does it not matter since I will have a thicker overall solid surface?

Should I attach the ply from under or above? Or is it just a preference thing? Under you can remove it. From above you live with it.

Thanks for all your quick help I am leaving tomorrow for my cottage to finish this up.

 

[Bud Cline]

Technically, THE BOOK says you should use TWO layers of 3/4 exterior plywood. If you cantilever the top it should have some additional supports such as "L" brackets or corbels. Forget the "strip thing" that's a bad idea I think. I assume there will be either chairs or stools associated with the cantilever. It isn't unusual for a person to use the counter top for leverage to rise from their seat, hence the need for the additional support. Try NOT to have a tile joint over the fulcrum of the cantilever.:no:

 

[toolbelt Tina]

Technically, THE BOOK says you should use TWO layers of 3/4 exterior plywood. If you cantilever the top it should have some additional supports such as "L" brackets or corbels. Forget the "strip thing" that's a bad idea I think. I assume there will be either chairs or stools associated with the cantilever. It isn't unusual for a person to use the counter top for leverage to rise from their seat, hence the need for the additional support. Try NOT to have a tile joint over the fulcrum of the cantilever.:no:

Thanks Bud
Should I put the 24" or 18" tile on the cantilever?

 

[Bud Cline]

How much cantilever we talkin' here?

 

[ccarlisle]

Not sure if anyone can say which of the two would best fit over a 16" overhand from a 'fracture' aspect...but I'd go with the 24" ones. Not sure exactly why just a gut feeling. But I also wouldn't go with the plywood from underneath i.e just doubling up the overhang area...I'd go with 2 1/4" thickness throughout.

But for peace of mind, I'd throw in some L brackets just to be on the safe side, as Bud pointed out. But that setup would do fine for a family with kids - just no 250-lb linebackers allowed to lean on it.:laughing:

 

[toolbelt Tina]

Not sure if anyone can say which of the two would best fit over a 16" overhand from a 'fracture' aspect...but I'd go with the 24" ones. Not sure exactly why just a gut feeling. But I also wouldn't go with the plywood from underneath i.e just doubling up the overhang area...I'd go with 2 1/4" thickness throughout.

But for peace of mind, I'd throw in some L brackets just to be on the safe side, as Bud pointed out. But that setup would do fine for a family with kids - just no 250-lb linebackers allowed to lean on it.:laughing:

i won't plan any football parties then.

what I meant was attaching to cabinets from above or below.
I am using complete sheets