Tiling onto 'solid' lathe & plaster wall

[simon]

Hi all,

I was planning to tile onto lathe and plaster in my bathroom. The shower unit will be tanked with the mapei kit to 2.4m. The rest of the room will be tiled to 1.2m.

The tiles are 600x300. 8mm ceramics which are 21kg/m2. The walls have around 25mm of plaster on

So will this cause problems? Or am I ok to go ahead and tile. Mapei cement based flexible adhesive to be used on a 6mm trowel.

Thanks !

 

[Ajax123]

I've not seen a solid lath and plaster wall for years. I suspect it will not be able to hold the weight. Better take off the lath and plaster and board or just overboard and use long screws...

 

[DHTiling]

I wonder out of interest , how much weight would an old lathe wall carry ..?

 

[Bubblecraft]

I haven't seen a solid one either in years. I can't imagine it being able to hold much.

I personally would remove it & re-sheet

 

[Ajax123]

I wonder out of interest , how much weight would an old lathe wall carry ..?

It would be damn near impossible to calculate because of the nature of construction. The weight bearing capacity depends on the strength of the keys between the lath the type of plaster used the age, the quality of lath timber, the amount of woodworm and wet rot etc etc etc... and you would be unable to inspect the guts of the wall without disturbing it and that will affect the strength....

 

[DHTiling]

So , pot luck Alan. :lol:

 

[White Room]

The trouble with lath and plaster it's only held by the mortar curling around the laths which is the scratch coat and a further coat as the floating coat and then the finish.

Once the first/scratch coat starts to loosen then nothing will hold it on and certainly any excessive weight dos'nt help the situation.

 

[Perfect Tiling]

Every time I come across lath and plaster walls I remove the plaster, leave on the lath and board over. The plaster is usually 12mm so doing this won't lose any room space. The other problem with lath and plaster walls is that they are so old that they are usually covered in paint, old paper, wallpaper paste etc...not a good substrate to tile to...esspecially with the size of tiles you are using. Plasterboard is a damn site cheaper than having to redo the job because it all came tumbling down!!!!

 

[SJPurdy]

Even if the plaster was clean and perfectly bonded to the lathes the maximum recommended weight of tiling on a plaster wall is 20kg/m2 and you have 21kg for the tiles and at least 5kg for the adhesive and grout. I would consider removing the lath and plaster and replacing with eg. Wedi board (properly fixed and sealed) in the wet area (no need to tank as well); + new plaster board (un skimmed) in the dry areas; or chnaging to a lighter tile.

 

[Diamond Pool Finishers]

Good thread here and pretty conclusive , re-move back to timber frame, re-board with suitable boarding of choice , prep, tile, simples ,more great advice from this forum for you ...........

 

[widler]

Sure i responded to this in another thread, must not of done it right, blinking iphones.
Same as everyone above, never seen a solid one.
For what it would cost, no more than a day with gear you may as well knock off and re board

 

[simon]

Ok thanks all, time to bite the bullet then I guess. I did try and add a photo but it wouldnt let me?

The other wall of the shower is an external wall with the plaster applied to. Will this also need pulling down and boarding?

i57.photobucket.com/albums/g233/sigurney/2D91A00A-AE8C-45AE-9095-38018DEF9CE8-772-00000077B7E28D45_zps3cb3e97d.jpg

 

[White Room]

Ok thanks all, time to bite the bullet then I guess. I did try and add a photo but it wouldnt let me?

The other wall of the shower is an external wall with the plaster applied to. Will this also need pulling down and boarding?

i57.photobucket.com/albums/g233/sigurney/2D91A00A-AE8C-45AE-9095-38018DEF9CE8-772-00000077B7E28D45_zps3cb3e97d.jpg

Is it lime mortar or a modern gypsum basecoat.....

 

[simon]

100year old lime

 

[Spud]

I tiled a bathroom this week infact where the customer didnt tell me they had lath and plaster walls ,they were concealed behind dot and dabbed plasterboard I only found out when i chopped back some making good he had done with my plasterers hammer to find out they were lath and plaster , The bathroom was 90% complete too , I finished the job and was paid but I did tell them that if I had of known I would not have tiled it