removing old floor tiles and retiling

[Unregistered]

just a question on removing old floor tiles and retiling in the bathroom.

the house is over 20 years old and it looks like the original adhesive used for the tiles was some sort of concrete adhesive. the floor tiles now have some fine cracks through them presumably from the lack of flexibility in the concrete adhesive.

my plan is to remove these tiles and retile. do you have to remove the concrete adhesive, or can you just remove the tiles from on top of the adhesive and retile over this? will there be any issues retiling over the previous concrete adhesive?

thanks
for your help

 

[Deleted member 9966]

Hi there

Firstly, :welcome: to forums.

The best thing you can do is to remove all the old tiles, and the old adhesive and grout as leaving this behind will not give you a decent flat surface to work with. Scrape as much of everything off as you can, and if there's still some stubborn adhesive left, try getting a wire brush attachment for a power drill and carefully sand off any excess being careful not to dig too deep and damage your floorboards

Once you've cleared the floor of all the old stuff, you need to find out how thick your floor boards are underneath because if you tile on to flimsy floorboards, you're likely to see your new tiles crack and the adhesive and grout break up.

There are specialist boards you can buy from places like Tile Giant that can be laid over your existing floor boards that you can tile onto. If you go for this option though, make sure the new board you put down is securely screwed to the floorboards beneath (try and screw into the joists to avoid pipework etc), preferably every 30cm or less if you can successfully find places for the screws to go!

Flexible adhesives and grouts are probably the best for a bathroom floor and if you have a Tile Giant store near you, pop in and speak to the people that work there, and they can advise you what is the best adhesive and grout to be using.

If you register with us (it's free) we can respond to your questions quicker.

Thanks
GRR

 

[brian c]

well answered Liz.

 

[Unregistered]

just some more information i didn't include to begin with. the concrete adhesive appears to be about 1 inch thick and the subfloor is a concrete slab.

i have taken all the tiles up now and am left with a flat surface, which is the top of the concrete adhesive with some minor bumps in it where the air chisel went too deep. my intention is to use some floor leveling compound to fix these minor bumps.

my question is, will the new tiles adhere appropriately to the previous concrete adhesive, or should i remove the adhesive and start bare on the concrete slab surface.

 

[Daveyboy]

Your concrete adhesive sounds like a screed layer on top of your concrete base/slab..are you sure you're not getting your terminology mixed up..a solid floor is normally made up of hardcore on top of the soil, layer of sand, damp proof membrane, layer of insulation, layer of concrete and finally, a layer of screed..

Assuming it is a layer of screed, you should prime the screed and then apply tile adhesive and tiles..if the minor bumps are minor, the tile adhesive will be sufficient to fill them...

 

[doug boardley]

right then, you've got a concrete floor that has been tiled, and you've removed the existing tiles?.adhesive (presumably cemetitious) is still adhering to tiles and floor, the house is over 20 years old?
there could be lots of reasons why the original tile work has suffered, ie, gradual subsidence in the foundatiions.
post some pics and introduce yourself to TF and hopefully we can assist you

 

[mlever]

thanks for your help, i have uploaded some photos that hopefully show the ?screed layer on top of my concrete slab foundations and the concrete adhesive used ontop of the screed for the tiles.

does this look ok to tile over? as long as it is all level.

thanks for your help.

 

[jay]

:welcome: that looks a lot like a rendered slab (been toped ) to improve surface or gain falls just tap over the top of it to see if its still sound (like looking for drummy tiles ):8:

 

[mlever]

i think the unsound portions came up mostly when i removed the tiles with the air chisel otherwise it seems solid.:8:

 

[jay]

as long as its sound you should be ablle to patch floor and slc over old addy

 

[Daveyboy]

From the picture, It looks like you have lifted some of the screed and if you say it came up easily with the tiles, then it has seperated from the concrete slab for some reason. There is a crack running through the concrete slab where the screed has been removed which suggests you have had some movement in the floor, sometime in the past, which may explain why the screed has seperated..make sure the rest of the screed is sound then re-screed the rest - it's quite deep for SLC unless you mix it with sand..let it dry then prime the screed and lay an uncoupling membrane over the screed before tiling..this should prevent your new tiles from cracking...

 

[White Room]

Whats the eml for on the screed

 

[Rob Z]

WB, I thought that too, but a closer look and it seems like that is some cloth mesh laying on top...maybe these were sheet mounted tiles?

 

[jay]

your right rob lookes deffo like mosaics on sheets :8:

 

[Unregistered]

help i am removing tiles from chipboard( floor tiles) wich have flexable adhesive and has taken 6hrs for 8 tiles so far,
using bolster and lump hammer, hard work, and tips out there cheers keith

 

[james fowler]

naw, this is an old thread but that guys floor there is not the foundation. I was searching for this answer myself and landed here. just to clarify ...my floor in our kitchen and is not on the ground floor there is a bedroom directly beneath it. SO NO FOUNDATION! I pulled up our tile and found this exact thing to a tee. seemed/looked more like they poured concrete over the foam part of carpeting which petrified the foam, then they tiled it. I am curious as to what he hell it is? i've been around for some time and been on multiple types of jobs and ive never seen anything like it. why it is so thick is beyond moronic. anyways yeah guess the only alternative is to get leveler or a bag of cement and fill the holes, after it sets use a grinder to help smooth where needed Im guessing. because taking it all out down to the wood would mean having to take out all of the existing tile too ( there may be cement board at the very bottom screwed to the floor itself but I dont want to find out.) I hope that anyone that comes across this doesnt listen to those other bits of "knowledge" its some sort of concrete type adhesive thats super thick - not a foundation, although it may have been directly applied on top of a foundation slab.