Hi,

Would Mapei Primer G be a suitable primer for a concrete floor that is having porcelain tiles applied with flexible PCI adhesive.

Thanks

PCI do a primer G as well...

Hi,

Thanks for the reply but I couldn't find PCI primer locally so have got some Mapei Primer G and just wanted to ensure it was suitable for concrete floors and porcelain tiles. There is a residue on parts of the floor from old lino, so thought it best to prime.

Am I doing the right thing?

When you say residue..what do you mean..?

I've tried to scrape off as much lino backing as possible but some of its just doesn't want to budge. I've used an industrial hot air gun and and even tried boiling hot water onto it to try and soften the adhesive but its still difficult to budge. Its as if there is waterproof paper stuck to the floor. Its obviously the final layer on the lino backing. If boiling water doesn't shift it then I'm starting to think that it should be OK to tiles over once primed.

You need to remove it.......

Try one of these attachments for a grinder..

Cupped Diamond Wheel


Fits standard type 115 mm angle grinders (100 mm x 22.2mm bore.)


Ideal for grinding away bumps in uneven concrete floors and keying old tiles or terrazzo before tiling

click picture to enlarge

weight 275g


Price: £18.88 £21.71 Including VAT at 15%


Wire Brush for Angle Grinder


A very aggressive wire brush for use in an angle grinder - You will be amazed how fast this works!

Use to remove all kinds of unwanted paint, adhesive, rust and other surface contaminants etc

Very good for 'keying' smooth surfaces.

- Hardend & twisted 0.5 mm steel strands
- 75 mm Diameter
- Standard M14 thread (fits all standard angle grinders)
- Max speed 12,500 Rpm

We recommend you wear suitable eye protection overalls and gloves while using this tool



Price: £4.49 £5.16 Including VAT at 15%

Both available from trade tiler.


Then you can prime and tile...some comps say don't mix primers but then an acrylic primer is a primer...

was in CTD today buying tiles for a customers wet room and had the same discussion with the guys in there( not me but another customer i was just eavesdropping) anyway the lads in there said that mapei adesilex p9 is perfect for concrete floor and has a built in primer? im not sure about this would love to know your feelings for future ref. cheers chris

P9 has a built in primer...........great advice NOT......


Ask them why does a gypsum substrate needed priming with P9 if it's built in..


Not all concrete floors need priming but priming can reduce the suction rate of the moisture and give more open time for adjustment...

Originally Posted by Dave

P9 has a built in primer...........great advice NOT......


Ask them why does a gypsum substrate needed priming with P9 if it's built in..


Not all concrete floors need priming but priming can reduce the suction rate of the moisture and give more open time for adjustment...

cheers dave

No problemo....

Thanks Dave,

Just got hold of the brush you described and will give it ago with the angle grinder tomorrow. Do you think it is still worth priming after removing everything with the angle grinder.

deffo as you will roughen the surface and create dusty finish...