Tile Over Existing Tiles

[Dave]

That response and specification from Mapei is to Basicly adhere the new tiles to the old , it does not in no way offer that the existing tiles are well adhered , after all your installation will only be as fixed as the first lot are .

IMHO mapei were wrong to spec the job without at least doing a Scmidt hammer test , there is also the issue when tiling over existing tiles on larger areas of expansion , you have the screed expansion , then the first layer of tiles and then adding another layer that will expand at differing rates.

If the floor has to be tiled over , then at least Ditra it IMO... Cutting the stress has to be a good thing .

 

[Dave]

Also , don't forget inserting your movement joints over the old ones and in door ways if necessary .

 

[Paul Finn]

Thanks David.

Mapei have made my life hell on this 1

 

[Dave]

No probs , let us know how you get on ..

 

[Rizzle from the Portizzle]

Ok, so I took advise and contacted Mapei, here's there reply. I'll feel much better sleeping now

Dear Mr Finn


************* has had an NBS Specification for this project (14/04/2015 NBS 433) out lining our recommendation for this project, which they should be able to provide you with.

However we can confirm that provided that the existing ceramic/porcelain tiles are suitably solid, sound and thoroughly cleaned and de-greased, they would need to be primed using Mapei Eco Prim Grip and the new tiles are to be bonded using Mapei Keraquick incorporating the Mapei Latexplus additive.


Any lose or damaged tiles are removed and the area suitably repaired before tiling.


We hope that this information is of benefit to you and if you require any further assistance please do not hesitate to contact us.

however we can confirm that provided that existing ceramic /porcelain tiles are suitably solid and sound? get out number 1 / and thoroughly cleaned get out number 2 /and de-greased get out number 3 .only you can guarantee your work there is NO adhesive company that will guarantee all of the above .so its always going to be down to you only
so is the floor sound
well get your self a a 3ft crow bar run it all over the floor the sound from solid to hollow will stand out thats your choice at the end of the day is it sound .should only take a couple of hours
chop a few random tiles out even if it sounds solid
tiling over tiles has been going on from the roman times so its not new
all the guarantee will be yours and yours only .

the only thing that will guarantee your work is your knowledge and experience
so its your call .

 

[widler]

nust imagine the amount of get out clauses Mapei can say if it fails,
"Sorry not prepped right"
"Sorry we have tested the addy and the water/additive ratio is wrong"
"Sorry the primer is to weak/strong"
"Sorry the original floor was loose"
"Sorry to many contaminants on original floor"
It be Like trying to get money out of your house/car insurance , a long hard slog
Having said that, if it's prepped right, the tiles are solid, as in they break up with a jcb in little pieces , the floor will be fine

 

[Andy Allen]

Is this a car showroom?
Are they going to be driving cars over it?

 

[J Sid]

nust imagine the amount of get out clauses Mapei can say if it fails,
"Sorry not prepped right"
"Sorry we have tested the addy and the water/additive ratio is wrong"
"Sorry the primer is to weak/strong"
"Sorry the original floor was loose"
"Sorry to many contaminants on original floor"
It be Like trying to get money out of your house/car insurance , a long hard slog
Having said that, if it's prepped right, the tiles are solid, as in they break up with a jcb in little pieces , the floor will be fine

Show me an Adhesive manufacturer who wouldn't try and get out of a claim.

 

[Paul Finn]

Is this a car showroom?
Are they going to be driving cars over it?

It is Andy

 

[Andy Allen]

Oooooh....brave man taking that one on..

 

[Paul Finn]

"Gulp"

 

[Dan]

Shouldn't be too bad. Try to get a few tiles up in various places to see how well they're stuck.

Mapei are a good firm. They'll back it if they've said they will. Worlds largest manufacturer of building materials, a measly car showroom isn't going to phase them.

Just degrease and prime well. For your own peace of mind more than anything.

 

[Paul Finn]

Yep Dan, Loads of prep work

Cheers Mapei

 

[peteablard]

I've done dozens of showroom floors for a company over the last 10 years, many of them over existing tiles. Maybe I've just been lucky but I've never had a single problem. Cleaned, primed then tiled, the majority done with Weber SPF. Someone is going to earn decent money tiling that, it might as well be you!

 

[Dan]

You can fly them down once you've prepped well.