Do I repair or replace wall before tiling?

[frekkles]

hello

I removed the old tile splashback and the Masonite looks like this. If I scrapped off the  excess and painted it with an undercoat, could I tile over the top or do I need to replace the wall?

[MitchellMc]

Welcome to the Bunnings Workshop community @frekkles. It's sensational to have you join us, and many thanks for your question about tiling over masonite.

It appears that most of this damage is just superficial. I note the area in the bottom left of your image looks a bit more extensive. Is the board still solid in this location? If so, you could scrape or sand the area and then apply a tile-adhesive primer like Dunlop 1L Primer And Additive. This will prepare the surface ready for tile adhesive. 

If the board overly flexes or that damage has compromised it, I'd suggest swapping it out for a new board.

Please let me know if you have any questions.

Mitchell 
 

[frekkles]

Thank you Mitchell.

The Masonite is solid which is great.

Thanks for the tip for the primer.