problem with new plaster - Tile Advice

[jimthetiler]

I tell my customers not to bother plastering walls where there will be a fully tiled wall.
It is recommended that you wire brush new plaster .
It is common practice to score the walls in a diamond pattern with a craft knife on plaster or if the walls are old use an axe (dear Henry)

 

[Spare Tool]

Scoring the walls in a diamond pattern serves no purpose other than weakening the skim even more.

 

[jimthetiler]

Scoring the walls in a diamond pattern serves no purpose other than weakening the skim even more.

Who told you that?

 

[Spare Tool]

Who told you that?

Go on then enlighten me what exactly does scoring the skim do?

 

[Blunt Tool]

Go on then enlighten me what exactly does scoring the skim do?

Does the same job as doing same to 6mm plywood on floors?

 

[Perfect Tiling]

There are only 2 things you should do to a floor thats been overlaid with 6mm plywood....
1. Rip the whole lot up and do it properly and IAW current standards
2. Tell the customer that your'e not doing the job.....cos it'll fail.

 

[jimthetiler]

Go on then enlighten me what exactly does scoring the skim do?

Glad you asked,first if the plaster is so bad that you just cannot fix to it then there is a bigger problem ie damp
If the plaster wall is lets say a normal plastered painted wall then any product you apply to the wall surface is still subject to the adherence of the paint,by providing a mechanical fixing you ensure the adhesive has a sound substrate to stick to.
I went to look at a repair job where some bathroom tiles came adrift the insurer came to look at the damage and said they will not pay out as there are no score marks in the painted wall,the job was not done correctly.
These rules do not apply to sand and cement walls that have not been painted only board or painted walls.
A welders hammer besides my tile clips will be you other little friend.

 

[Spare Tool]

Well Jim you've opened a new page for me there... I overboard (dot and dab) 90% of walls and mechanically fix through to brick/block with screws plugs and washers.
If overboarding is not an option and the wall is painted I would remove the paint with either a scrapper or 50 grit sandpaper.
I still cant see how putting a couple off mm of a scribe in the wall is giving me any better adhesion to the paint surrounding the scores, must be literally thin slivers of adhesive that's actually stuck in the score groove and not hanging onto the paint?

 

[Waluigi]

Which washers do you use? Is there a specific product?

I usually get my scutch hammer on walls that are iffy to get me a key and then plug and screw.

 

[Spare Tool]

Which washers do you use? Is there a specific product?

I usually get my scutch hammer on walls that are iffy to get me a key and then plug and screw.

Use the pro warm insulation board washers with a 75 or 100mm screw depending what's needed, 12 in an 8 x 4 pboard

 

[Waluigi]

So pretty much the standard foam board washers? The metal type.

Not done pro warm yet

 

[Spare Tool]

So pretty much the standard foam board washers? The metal type.

Not done pro warm yet

Yeah that's the ones ,or you could just score the paint...


Apparently

 

[Wishiwasatoptiler]

I do the same as you Andy, although if its emulsion paint, covering it in tub addy, leave on 15 mins and scrape off. Works a treat.