Black limestone indoors - TilersForums.com

[mrct]

Just about to lay 70m2 black limestone indoors, read a lot of horror stories so just looking for an insight. The customer / stone supplier is supplying all sealers. I intend to seal prior to laying, fronts sides and backs. I intend to seal again prior grouting and after grouting.

The horror stories I've read on here are all about marks etc. is there anything I need to look out for ?

Cheers.

 

[Lithofin BOB]

Just about to lay 70m2 black limestone indoors, read a lot of horror stories so just looking for an insight. The customer / stone supplier is supplying all sealers. I intend to seal prior to laying, fronts sides and backs. I intend to seal again prior grouting and after grouting.

The horror stories I've read on here are all about marks etc. is there anything I need to look out for ?

Cheers.

I am concerned with the pre seal before installation , I know many guys do this , we/ I would never recommend this .I am more concerned with the suggested sealing of the back, I would never recommend this due to poss failure of bond. I have discussed this with all the larger manufactures and not one would recommend this with an impregnating sealer.

Are there possible primers for this?

Most of my problem floors are moisture related, a lot of the time with the darker stones ( basalt a real prob over the last two years). Although rapid setting is used, this is not rapid moisture release and in some cases moisture is trapped leaving white salt/ eff in the stones, some of these issues in some stones are not reversible. There are moisture crystallising adhesives these can shorten dry times before sealing but still have limits. I hope the guys will comment.

Generally I suggest to lay.

Release all moisture , when fully dry seal face and edge. 1-2 saturations depending on density and porosity

Curing time / min 12-24 hr for solvent

Test grout removal over sealed surface finish ,Grout

Once fully dry and all moisture gone seal again over all.

Note;I am not a fitter, just deal with problem floors.

Sure the guys will give you a full run through. I also look forward to the responses

 

[mrct]

Cheers for this, wasn't to sure about sealing the backs however with basalt I've heard bad things of trowl marks etc bleeding through as they were not sealed so I was a little worried about this on black limestone.
Think I'll go with sealing front and sides. Stone seller is providing the sealer.

 

[Lithofin BOB]

Cheers for this, wasn't to sure about sealing the backs however with basalt I've heard bad things of trowl marks etc bleeding through as they were not sealed so I was a little worried about this on black limestone.
Think I'll go with sealing front and sides. Stone seller is providing the sealer.

The black trowel marks coming up through ( water marking migrating from the adhesive) when a tile is removed on inspection ,the tile is often just placed upon the adhesive on the ridges , not 100 % bedded similar to dot and dab ( points of contact) so you get the moisture coming up as trowel marks, even worse if this is trapped by a pre seal.

Full bedding is key as always, no issues then with marking. sure the guys wil comment

 

[Sean SML Tiling]

Just back butter the tiles if your worried about trowel markings.

 

[jonnyc]

Definitely use rapid set rather than normal set and we always back butter tiles as well.
bob
what do you think of the presealing of stone that one of our london stone companies carries out using stainstop.

 

[Dave]

When you say black limestone ? , what is it .

There are more than one type and stone identification helps with treatment advice.

 

[Dave]

Just to add to above comments on moisture staining , again this depends on the stone being used , I,e thickness and porosity .

 

[Lithofin BOB]

Definitely use rapid set rather than normal set and we always back butter tiles as well.
bob
what do you think of the presealing of stone that one of our london stone companies carries out using stainstop.

Hi jonny,

Generally no, I would never recommend to pre seal prior to instalation , I know many fitters and contractors that do and a lot that have had no problems. Lots that do .There a few factors that we need to consider.

Density and porosity of different stones; stones drawing and Releasing / holding moisture at different rates, giving us patchy floors sometimes .

type and quality of sealing product used; what type of pre seal is used on these stones , sometimes water based will not bite us as much , ( still wouldn't recommend a pre seal)

application of the sealing product; after viewing stones being pre sealed , some times this will consist of a wipe over or a quick spray. Some are over sealed

Just as a note, if you guys get a pre sealed stone to fit , test that the pre seal is suitable and giving you full repellance and grout release, have had many issues with some pre sealed and guys getting bleed across a whole floor, when cleaning up grout .test on an unlaid tile.

colour of stone; coloured stones can be problematic too,

Whites and lights can water mark under the pre seal, certainly if not fully bedded, floors can look a lot darker ,white marbles often get odd tiles darker than the other often due to pre seal or sealing to quickly after install.

The darker stone will show a white cloudiness / patchy poss salt or dead seal, if salts ,this can be difficult sometimes impossible to remove , I had 400 Sqm basalt ripped up 4-5 weeks ago due to pre seal , gutted -beautifully laid

adhesive used; which to use , rapid ,normal, cystalizing .rapid setting is what you guys advise but I still have a lot that use the slow, this moisture can linger under the seal Causing above issues .
Rapid setting yes!! But it's not rapid moisture release,

Is it only moisture from adhesive we need to be concerned about; consider screeds , are they really dry ( the builder says it is!!!!!) also self levellers , look how much water we put into these , it all needs to release or can be trapped under a pre seal.

I am Sure there are a few more reasons,you know I get a bit negative some times , but have had three floors this week with pre seal issues , get 20-25 calls a day with problem floor as you know jonny and most are moisture related. Of Course the conversation starts " your seals done this to my floor"

Not the seal, now "when was it applied"

So to keep it short !! Lol. No, i have concerns

 

[Dave]

As above ^^^ , still waiting for my post to be approved . Each stone has to be taken at face value and treated accordingly.

 

[Lithofin BOB]

As above ^^^ , still waiting for my post to be approved . Each stone has to be taken at face value and treated accordingly.

Thickness definatly is a consideration , and I totally agree that each stone should be delt with and treated accordingly , difficult in cases where we are now dealing with hundereds of different stains of natural stone. Certainly In cases where we have sandstone , granites , limestone which are not geogically these stone but are being sold as them . So installations can be tricky at times, correct guidance from the supplier I suppose is key, but not always available .

 

[Dave]

So true bob , some stones are sold without any advice given to the customer etc.

back to the OP , Fila chem now sell a product to coat the back of stone tiles to prevent moisture migration/staining bleeding through.
Not tried it myself yet but worth thinking about.

if it is Basalt , then deffo use a rapid setting adhesive suitable for stone .

 

[Lithofin BOB]

So true bob , some stones are sold without any advice given to the customer etc.

back to the OP , Fila chem now sell a product to coat the back of stone tiles to prevent moisture migration/staining bleeding through.
Not tried it myself yet but worth thinking about.

if it is Basalt , then deffo use a rapid setting adhesive suitable for stone .

Cheers David , I will have a word with Lisa ,Martin ( fila) , get some more info and test. This product may be more of the suitable primer rather than the guys using an general impregnator to block , which I spoke about above.

 

[Dave]

It was mentioned to me by ex Fila guy Mark ruthern .. This is the product bob >> http://www.filasolutions.com/en/products/natural-stone/protectors/stain-protectors/filapw10.html

 

[Lithofin BOB]

It was mentioned to me by ex Fila guy Mark ruthern .. This is the product bob >> http://www.filasolutions.com/en/products/natural-stone/protectors/stain-protectors/filapw10.html

Thanks David , yes know mark well, have read product sheet , looks good for stopping migrating contaminants oxides, efflo.

But the conversation is moisture related on pre-sealed , this is a breathable product and will still release moisture due to hydrostatic pressure which will push through / possibly get trapped and still could be an issue with pre- sealed products.

If the project was not pre sealed, there may be no issue. Thanks again for link i will again be interest to look/ test into this . Bob