Mosaic tile on stair riser advice

[jstonemo]

I am planning on installing mosaic tile on interior stair risers, but when I pulled off the carpet I see that the risers are particle board. I am wondering if the risers need to be removed and use something else like 1/2" backerboard or plywood or if the particle board is good since it won't be seeing foot traffic like a floor would. I have some left over Redguard that I can put on the particle board if that would make any difference.

thanks

[Houston Remodeler]

Is the plywood stable? Strong? Flexible?

[John Bridge]

Hi John,

I think Paul missed the part about particle board. It'll have to come out. You'll need a really strong and stiff base for your tile. 3/4 inch plywood would be the minimum, and then I would suggest a tiling membrane over that.

[jstonemo]

Thanks, that’s what I figured. Already have the 3/4” ply cut down ready to install.