Help! tiles loose and lifting

[t5_nel]

Hi all,

I posted here a few months ago while I was getting estimates to have a large floor area tiled.

A large amount of the floor was wood parquet floor. The job seemed to go well and all was well BUT recently some of the tiles came loose (grout started to crack) and then some clearly are no longer attached well to floor.

The tiler said that as the parquet was still sound on the floor and not varnished adhesion would be okay. So basically he said we did not have to lift the wood and it would be fine

I would say about 10% of tiles are affected. The tiler came back to look and did painfully(!) accept responsibility. He has agreed to rectify it at his cost (parts and labour) but has said that we need to prepare the floor - so although I am pissed off about it I am just going to move on and accept that it happened.

From his research he thinks that what has gone wrong is the fact that the parquet floor is on bitumen and this causes the issue (I think Dunlop - adhesive manufacturer said this). Apparently you should not even latex over bitumen as ther can be issues

What I really want to know is what is the best course of action now as it is my responsibility to prepare the floor for retiling. Basically tiles and wood need to come up (tiler will do that) and then I will be left with sticky old bitumen on concrete floor. Tiler does not want to go on top of bitumen as adhesive manufacturer said bad idea. Also some of the rooms will not need retiling as they were on concrete , latex or marmox board (complex I know) and I would like to keep the levels as close as possible.

Option one is to ply it all - can I use a thinner ply than 18mm??? This will be awful for the levels. I was justwondering because the ply does not need to level the floor or reduce deflection but just provide some height and provide a good substrate for bonding

What other options are there that will not cost the earth (I have been quouted £900 inc. to ply the area)

Thanks
More detail available
Tim

 

[Fekin]

How many sqm needs plying out, as £900 for laying down some ply seems horrifically expensive.

 

[t5_nel]

Thanks for the reply...

Off the top of my head it is about 50 sq m.

quote was 375 materials and 480 labour (2 guys 1.5 days) a LOT of screwing!

 

[DHTiling]

HI. there you can tile onto bitumen with no problems if you use the correct adhesives here's a guide for your tiler to follow which will show him what preperation to do..

broken link removed

hope this helps.. dave.....

 

[t5_nel]

Thanks dave, the issue is now that the levels will be wrong because some rooms will not be lifted ( as they were not bitumen/wood substrate to start with).

I will check the adhesive guidance but I am very interested to know if you can get away with thinner ply on top of concrete slab floors...

 

[DHTiling]

you can ply out if require too, but prime under side and edges of ply with acrylic primer and screw down with brass or gyproc screws so they are not affected by moisture .
the ply thickness depends and what height increase you need and as long as they are screwed and plugged at no more than 300mm centres there will be no deflection in the floor... good luck.. dave..

 

[GazTech]

Thanks dave, the issue is now that the levels will be wrong because some rooms will not be lifted ( as they were not bitumen/wood substrate to start with).

I will check the adhesive guidance but I am very interested to know if you can get away with thinner ply on top of concrete slab floors...

Tim a 6mm cement backer board can be adhered to the slab floors.Also a 6mm cement backer board ring nailed will be less labour intensive on the parquet flooring, but be sure to use a flexible adhesive and grout on these areas.

 

[CJ]

Get rid of the parquet flooring........otherwise you will probably have the same problems again at a later date.

Tiler should have know better.

 

[t5_nel]

Thanks for the comments guys a few things to say

1)Parquet is definitely all coming up this time!
2)Good news about ply thickness
3)Is cement backer board the same stuff as 'marmox' and wedi board?
4)Can you really nail this board? This sounds much faster!!! How much does this typically cost per sq m. over 40 - 50 sq m.?

The reason I am concerned about levels is because some tiled areas are fine (kitchen , cloakroom) as they did not have parquet originally. 6mm marmox board on a bed of some mapei adhesivewa used to bring the level of these rooms up to parquet level so that the door thresholds would be pretty level.

I am very interested in the cement board idea but I am worried that this will be an arm and a leg in terms of cost.

 

[DHTiling]

hi t5 nel .. the cost to ply floor should only be a day for 2 men, i have resently plyed a floor wich needed to screwed and plugged and i did 32sq mtrs in day on my own so 2 should do 50ish in a day easy. as regarding cement boards you will need two lots of adhesive , 1 lot to stick boards down with and then another to tile with so i think plying and labour will be cheaper for you...

 

[t5_nel]

Dave thanks again you have reassured me that there is a way forward.

Out of interest what depth did you plug to and what size screws, what plugs? I am guessing you want say 20mm in the concrete and I agree about using the zinc coated screws.

I am tempted to DIY this as I can prob get the help of a couple of others for a day.

I guess the process is
1 mark where the holes are on the board
2 put board in position
3 drill ply with wood bit
4 mark holes on concrete
5 move ply and drill concrete with masonry bit
6 plug and screw

then repeat 3000 times...