When is priming needed?

[Miles]

I am going to tile a kitchen and have 3 different substrates:
- plasterboard
- old tile adhesive repaired with housefix
- painted old masonite repaired with filler

# When do I need to prime before tiling?
# Can I use any paint I have at home instead of a large bucket of primer for one square meter?

 

[jon_h]

Prime the plaster and filler. And you can't tile on the träfiberskiva, not sure if you were thinking of doing that?

You can buy a one-liter bottle of primer for about 70 kronor, paint does not serve the same function.

 

[Miles]

Prime the gypsum and filler. And you can't tile on the träfiberskiva, didn't know if you were planning to?
You can buy a one-liter bottle of primer for about 70 kronor, paint doesn't serve the same purpose.

Thanks for the answer!

The träfiberskiva is a side of an older tall cabinet:
- will be tiled only on a 60x55 area
- and there were tiles on that side that I have removed
... why can't it be tiled?

Haven't seen anywhere that gypsum needs primer, did you mean the entire gypsum board or just where it's filled?

 

[jon_h]

Yes, it is possible that it will stay, but it's not certain. It is too soft and flexible a material to guarantee that it will hold in the long run. But on a sufficiently small area, it can work. Use flexfix and flexfog at least.

The plaster doesn't have to be primed, but it doesn't hurt to do so. This prevents it from absorbing the water from the fix. The same goes for the filler, it's not absolutely necessary to prime it, but you get a little better adhesion and the fix has time to set better as the water stays in it.

 

[Miles]

Cheers! ... then it will absolutely be primer because I have large heavy 60x30 tiles on 2 sides and up to the ceiling on the gypsum side, so I prefer to play it safe there.

Awesome forum this is