Fekin

Just had another call from customer, lol

In the kitchen theres an old fire place, in the fireplace shes got an oven there already and a hob to be fitted into the work surface inside the chimney.

Now the chimney has been boarded out at the front with thin plywood years ago, it did have a lerge thin metal sheet covering the ply to protect against the heat from the oven.

This sheetings now been ripped off, leaving the thin plywood backing blocking off the chimney and the gas fitter won't fit a gas hob in there because the backings obviously flammable.
She now needs this tiling but I think it is far too thin fto tile onto and as a hob needs to be fitted there might be a large degree of flwxing in the ply backing which would ruin any tiling and grouting, so im looking at replacing the ply backing with something stronger to tile too.

Since a gas hob is going to be close'ish to the backing thats going to be tiled anyway, do I need to use any special backboard, or will thicker plywood or plasterboard be ok for legal requirments ?