Kitchens – Should the support structure for a kitchen island be built on top of tiles


I'm currently remodeling my kitchen, and I'm going to have a 9'x40" granite island in the new kitchen. There will be only two 33" wide base cabinets under the granite top, one on each end. The two base cabinets definitely will not have enough strength to hold the heavy weight of the granite top.

My contractor is going to build a support structure to support the weight of the 108"x40" granite top. He laid a cement board on top of the subfloor in the kitchen, then tiled (porcelain) the entire kitchen. He is planning to build the support structure on top of the tiles, but I'm not sure this is the right method.

Is building the support structure for the granite on top of the tiles the proper way to do the job, or should the support structure be built on top of the subfloor, or the cement board?

Best Answer

The tile beneath the pony wall should be removed.

One of the things that a thinset and tile underlayment do is decouple the tile from the subfloor beneath it. By contrast, you explicitly want the pony wall supporting the slab to be coupled to the subfloor.

Then the pony wall should be secured both to the subfloor and the cabinets against it.

The sub-counter (I recommend using MDF) should then be a single piece attached directly to the cabinets and the pony wall.