Forgot to prime behind small area - help!

[classybird]

Hi, been working on a big bathroom and at the start of each day have been priming the area I'm going to work on. Except one day a couple of days ago l got through way more than I thought. And I have only just realised that three rows of tiles (21 metro tiles to be precise) on one wall were put up without having primed that area first. Now I am paranoid about problems arising or tiles falling off the wall or something. Has anyone got any wise words for me please or is there anything I should do?

 

[Swwils]

If the wall was in good condition, clean, and dust-free when you applied the tiles and the adhesive was suitable for the surface material, you're likely not going to face any immediate issues. The purpose of the primer is to provide a more optimal surface for the adhesive by reducing the porosity of the substrate, helping prevent rapid drying of the adhesive, and improving the bond between the adhesive and substrate.

However, not using a primer doesn't automatically mean your tiles will fail, especially if they've been up for a few days and haven't shown any signs of problems.

The bigger concern might be long-term performance, particularly if the wall is in a high moisture area like a shower. If this is the case, keep an eye on the tiles. If any start to sound hollow when you tap on them, that could be a sign of debonding, and you might need to remove and reinstall those tiles.

 

[opps]

Why not prime all of the walls from the outset?

What are you tiling over, and which adhesive are you using? If using cement based adhesives over gypsum plaster without primer (SBR/etc), there is a risk of ettringite crystals forming.

Ettringite formation over gypsum screed - Tiling Advice

Just updating a previous post that I made in February about using cement based adhesive over an anhydrite calcium sulphate (gypsum) screed with no primer. Took four months for the problem to develop but tiles are a write off and will all now have to be ripped up and replaced. Symptoms start...

www.tilersforums.com

As @Swwils says, just monitor it over the next few months.

Best'o'luck

 

[classybird]

If the wall was in good condition, clean, and dust-free when you applied the tiles and the adhesive was suitable for the surface material, you're likely not going to face any immediate issues. The purpose of the primer is to provide a more optimal surface for the adhesive by reducing the porosity of the substrate, helping prevent rapid drying of the adhesive, and improving the bond between the adhesive and substrate.

However, not using a primer doesn't automatically mean your tiles will fail, especially if they've been up for a few days and haven't shown any signs of problems.

The bigger concern might be long-term performance, particularly if the wall is in a high moisture area like a shower. If this is the case, keep an eye on the tiles. If any start to sound hollow when you tap on them, that could be a sign of debonding, and you might need to remove and reinstall those tiles.

 

[classybird]

Thank you so much for your reply, the walls were newly plastered and clean. These tiles are higher up on the sink wall next to a big window. The shower has been tanked and everything done properly around that bit.

 

[classybird]

Why not prime all of the walls from the outset?

What are you tiling over, and which adhesive are you using? If using cement based adhesives over gypsum plaster without primer (SBR/etc), there is a risk of ettringite crystals forming.

Ettringite formation over gypsum screed - Tiling Advice

Just updating a previous post that I made in February about using cement based adhesive over an anhydrite calcium sulphate (gypsum) screed with no primer. Took four months for the problem to develop but tiles are a write off and will all now have to be ripped up and replaced. Symptoms start...

www.tilersforums.com

As @Swwils says, just monitor it over the next few months.

Best'o'luck

Thanks for your reply also. I always used to prime everywhere at the start, however when I then went on a tiling course at a later stage the tutor said something about if priming you should be tiling the same day, which lead me to doing it in stages.

The adhesive on the walls is flexible slow set so it will be cement based. No idea what type of plaster it is, looks like the regular stuff builders always use.