raising height of windowsill and then tiling it

[sacbina]

new kitchen worktop much higher than old windowsill so have an idea to raise windowsill height and then mosaic tile area

plenty of room within existing window frame so won't interfere with window itself

but wondering what to construct this extra height from. tiling onto wood seems to be a no-no, it will be directly behind a tap and therefore legitimate splash zone for ds washing up.

the area needs to be built up at least 70mm

having brain fog and can't see see the obvious solution, please help?

morning bumpity bump

Why is tiling onto wood a no-no? Are you sure?

pretty sure it was to do with wood warping and potential for water ingress

I've also found that tiling onto wood doesn't work as the adhesive warps the wood.

You could use plasterboard, with a frame underneath made from wood, or you could use breeze blocks- they are surprisingly easy to cut to size with a hand saw.

breeze blocks, brilliant