What do you think?

Dumb!

Remove the tile is the best way with guaranteed success. Tiling over the old tile would be acceptable under the right circumstances. The board thing should be forgotten immediately.

 

What would be the "right circumstances?"

Thanks

 

The right circumstances would be about $17/square foot.

 

The right circumstances to successfully tile over the old tile would be if the old tile was still tightly bonded to the substrate. No loose tiles no cracked tiles.

If it is glazed tile the glaze would have be challenged, disrupted, sanded, gouged, ground, scarified, abused in some fashion.

THEN the adhesive should be a quality modified thinset that you mix yourself - no premixed trash.

 

Thanks Bud....

We're a general contractor that does some incidental tile in-house, (i.e., kitchens, baths, etc...). I've been asked to quote a rather large project of re-tiling two complete commercial locker rooms.

The GC asked if there was a possibility to go over the existing, rather than demo, as a means to utilize the savings to do other work.

The existing is old, but in excellent condition. it is glazed. I haven't calculated the s.f. yet, but would estimate aprx. 8,000 - 10,000 s.f.

Just trying to figure the feasability of going over vs. demo.....If it would realize a substantial savings in both or either the cost and/or time areas.

 

Before saying yes, I would physically go over every single aquare inch of that tile and make sure there are no cracks-- not in the tile, and not in the grout. Additionally, I would take a butter knife or some other similar metal object with me and tap every bit of it to make sure there are no hollow spots.

IF I were to find no problems, obvious or otherwise, only then would I consent to something like this, and even then, there would be a disclaimer in the contract that I would not be liable for existing conditions that were not apparent prior to installation.

 

WHOAH! HOLD ON!

tnt specialty: "I was asked today about the feasibility of installing a board-type separator over existing wall tile and install new tile, rather than demo the existing."

When you said "over existing wall tile" I had visions of a twenty-five square foot backsplash or maybe a 150 square foot wainscot - NOW I find out you are talking about 10,000 square feet to cover up. That could be a very different story.

I would agree with Bill Vincent. Be deliberate and investigate every square foot of the existing tile. "Sound" it everywhere. Shake the walls to see what happens. Is the wall framing metal stud or wood stud? Grind everything to rid the glaze. Look for loose grout and signs of deterioration of the original bond.

Ten K of wall tile is a big bite to take without being thorough with the discovery process first.

 

Sooooo.......

I get the hint that there is a method/adhesive specifically for applying new tile direclty over the existing?

I originally thought to mechanically fasten a cementous board type backer over/through the existing tile, fastened to the wall structure. Then procede as new installation.

Any comments to either method?

Thanks again.

 

I get the hint that there is a method/adhesive specifically for applying new tile direclty over the existing?

If you use one of the better grade modified thinsets and the old tiles are scuffed you'll be OK, don't try to cheap-out on the thinset.

I originally thought to mechanically fasten a cementious board type backer over/through the existing tile, fastened to the wall structure. Then proceed as new installation.

That wouldn't be as easy as it sounds and it would be less labor intensive just to remove the old tile and wallboard and start over from there.:thumbsup:

 

I'd personaly tell them no and be done with it. Every time I take a shortcut it bites me in the ass.

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