Pietra Serena Sandstone 800x800mm help - Tile Advice

[jonnyc]

If only it was as simple as installing 4 large tiles you can walk around in the vid!!!!

Couple of points from me to consider with this stone , moisture has to release fully proir to impregnation ,either from cleaning or instalation. She can bite you!!!

On the attached film ,I am a little confused with the suggestion of impregnating the stone first with a hydrophobic only impregnator , as this then could block further impregnation with the w68 a water based product , which will give you your final water and oil protection.
For me , I would use the w68 for both coats ( prior and after grouting) this will then enable you to give deeper protection with the first saturation and top up with the final application, including your grout,greater protection against oil based staining. I would give fila a call to discuss this on their tech line.

They also recomend a clean with deterdek ( a buffered acid ) be aware ,not all pietra serena is acidic resistant and I have seen many of these floors pitted out with the use of these types of products, ( test first for suitability, it may be fine)

Test your grout release on an un- laid impregnated stone prior to completing any section, be confident you can work in controlled sections to complete and clean away. Impregnators line the capillaries they do not fill them, so grout can still contaminate the face even if fully impregnated and these then will either will require the acidic approach or possible mechanical removal with kgs/ twister type pads .

It's all in the testing

Bob
Not been on for a while but this is interesting thread . The dreaded pietra serena ! Where do you start with this stone bob my friend ?
I know you've attended enough **** ups bob in your time as I have with this stone and I've fixed many serena floors with both presealed in iltaly or uk or unsealed . All I know is that you have to be very careful indeed. So careful in fact that I refuse to fix this stone unless on my terms .
Rapid set adhesive is a must for a start .but given that route taken that's just the start of potential problems .
I won't even consider a job outside if not presealed in italy by quarry.
Fixing stone not a problem for us as long as in rapid set and solid bed . Doesn't matter how you lay bed out as long as solid bed underneath achieved.Notched trowel with stone that can vary few mm is def non no .
The real problems come after fixing .
The only good and easy best result I have had is by using grout that is polymer free regardless of sealer used and how much !!Use a polymer modified grout even if rapid set like Mapei and you will get trouble with staining to face of stone in my experience I'm not Talking picture framing I'm talking staining .
If you just grout the width of squeegee rather than whole face you will see the problem easier . 90 % of stones we lay we cover face of stone because the light staining can cover the problem but with pietra serena it looks terrible with whole face covered or just width of squeegee.
Regarding sealer my preference has been Lithofin stainstop mn inside for last 20 years for all my stone jobs and especially for serena .as much as I like lithofin i would never use stainstop Eco or w on serena inside or out .but I have used fila similar impregnator and others but serena can stain so easily
If polymer modified grout used .
You might suggest that if you don't use polymer modified grout over underfloor heating then you are not going to get a problem . I think not .beware this is is not a job you want to take on without a lot of understanding and experience .
That said walk in to any Apple Store in U.K.
And it looks good evennwitj loads of traffic . What secret do they hold to have exclusivity of good looking product ,

 

[Stuart_AC]

Hi All,
Thought it would be good to give an an update on how I’m getting on with my project. I’m about 1/3 of the way through and thought I’d share some observations.

Tile
Cutting the stone is easy – I bought a cheap ebay bridge saw for £300 which chews through it no problem. A small grinder also makes short work of it.

When handling you have to be careful as the edges are fragile. It’s easy to pop a corner by standing it up without protection. A dollop of paint on the concrete floor even caused enough pressure to chip an edge when a tile was stood up momentarily.

The tolerance of the tile has its own set of challenges. They’re 800x800 but on the odd occasion a tile can be +/- 1mm. So I have to be careful with tile selection when laying. They’re also honed and I’ve found that a few tiles have slightly bowed where the grinding operator has maybe run off the edges a bit too vigorously creating a bowed effect a bit like you’d see in a ceramic. It’s so minor it’s difficult to perceive but it left me scratching my head once or twice when I had 3 corners matching height perfectly and the 4th sitting high or low.

Laying the tile
I’m using BAL PTB Rapid set adhesive and finding it good to use. This stone can be susceptible to moisture staining from the underside if rapid set isn’t used. There’s also the option to mix the PTB with an additive to quicken the set but I didn’t bother with that and have not had any issues.

.... cont

 

[Stuart_AC]

...cont.

I bought a load of Genesis Tile Clips but generally not using them as the tile is so heavy that it snaps the clip before the tile can be pulled level. I’m using the odd one where needed and assist the lift with a trowel as not to snap the clips. Note – it’s only being lifted 1 or 2mm so the theory of lifting a tile clear off the adhesive isn’t an issue. I’ve clipped in tiles and raised them a few mm only to have to lift the tile again for some reason–each tile I’ve checked for adhesive coverage after it has been lifted and it has been ok.

Pretty much every 2nd tile is laid then comes straight back up for some minor scrapping/calibration. There can be a small deviance in the thickness of the tile by +/- 1.5mm. They’re meant to be 20mm so the deviance makes it difficult to be consistent with adhesive to achieve. At the beginning of the adhesive batch (when it’s quite loose) it’s possible to stand on the tile and squash it down. However nearer the end of the batch when it’s stiffer that’s not possible so the tile comes back up. It’s tough getting the tile back up but it’s a good opportunity to see that I’m getting good consistent coverage to the adhesive.

Setting out
If you look back on the thread I said I was planning to lay a master setting out line the length of the house and tile off them. I’ve revised that thought as it’s better to ensure that each group of tiles are level with each without issue before moving onto the next part. Also if I had set up a tiled line then I would have had to ensure clear pockets under the tile clear of adhesive so that the levelling clips can be inserted and be free to move. You can’t bed a clip in at the end of the day and then start the following day as it has to be free to move in order to pull the up the tiles.

Nothing’s grouted yet. I’m planning to follow the procedure and use the products in the video I attached at the beginning of the thread so will let you know how I get on.

 

[Old Mod]

Looks good but a few of your theories about clips are flawed. And you shouldn’t be lifting any tile from the floor with the aid of a clip. You’re putting that piece at risk. Whether it feels like it or not right now. Remove the piece and apply more adhesive. It’s a stone and ultimately weak. Corners will break if they are not fully bedded.

 

[Stuart_AC]

Thanks 3_fall,

I don’t think I have a flawed theory about the clips – more likely I didn’t explain my use of them clearly enough.

My understanding is that the purpose of tile clips is to eliminate lippage by pulling tiles into alignment – which generally involves lifting one of them by 1 or 2mm. If you watch the manufacturer videos that’s what happens. What I’ve found is that the large format sandstone tile is too heavy for the clip to lift (part weight of the stone, part suction of the adhesive over an 800x800 tile).

Where clips were applied (maybe 5 tiles over 75 laid so far) I’ve placed them 100mm in from the corner as not to stress the stone. On a few occasions where I used a clip and it turned out that it was more than a 2mm lift the then the tile was taken up and more adhesive added.

What I was trying to explain is that when a clipped tile (which had been raised 2mm by the clip but it wasn’t enough) was taken up for more adhesive to be added the spread pattern on the floor and tile suggested that the adhesive was giving good coverage even after it had been lifted slightly with a clip.

So I think my theory is right in that a 2mm lift by a clip doesn’t leave the tile without good adhesive coverage. Although that said if your adhesive mix is dryish it might be different. But my tiles are back buttered and the adhesive mixed exactly so that wasn’t an issue.

Generally though we’ve given up on the clips for this job but I can see their benefit for smaller tiles.

 

[Old Mod]

I’m going to have to disagree Stuart I’m afraid.
It’s becauuse of practises like these (lifting tiles with clips) that companies like Ardex are now refusing to honour guarantees against floors laid with clips, because of their improper use.
Clips are not designed to lift tiles, eliminate lippage, yes.
This is done by correctly bedding the piece in question with a full bed and holding it in position until the adhesive sets and no more.
Adhesive is prone to minimal shrinkage on curing and this more often than not, on a well laid floor, is what causes lippage.
So I’m afraid we’ll have to agree to disagree.
This not intended to dig you out, merely give you more information on your install.
You’re to be commended on your level of commitment and research, and indeed the aesthetics of your final finish, however I feel it would be irresponsible of me not to point out that I feel that your knowledge of clip use is in my opinion, is flawed.
I do actually look forward to seeing the final result.
Good luck.

 

[Stuart_AC]

Cheers 3_fall,
I don't disagree with you as that makes perfect sense.

I do think that the clip marketing is a bit off then as it shows tiles being pulled into alignment to eliminate lippage rather than only applying clips to stabilise during curing. That's what probably lulls the unknowledgeable into a false sense of security.

On reflection I think in my situation the clips have been used immediately after a fresh mix - when it was wettest - they hold the tile in place whilst the adhesive sets as the weight of the tile (30kg) can cause it to sink when the adhesive is overly wet. But as I've only used clips on 5 out of 75 tiles it's not something that's happened often.

For the most part the job has been old skool lifting of the tile to either subtract or add adhesive to make it level. Probably every tile comes back up at least once which makes for heavy work!

 

[Old Mod]

As I said Stuart, the post wasn’t intended to dig you out or make you feel uncomfortable, merely to increase your knowledge.
I know all about stone being heavy work.
I now mainly install ex large formats, up to 3.2m in length and clips are essential in this work, and it’s extremely heavy work.
So I do understand your difficulties.
Good luck, and please do come back and show us your finished floor.
Marc.

 

[Stuart_AC]

Hi guys,
I've finished laying the tiles and have applied the pre-grout sealer as discussed earlier in the post.

I'm now grouting with Mapei Keracolour GG 113. I did the first room last night and this morning it still looks wet at the edges (picture attached)

It doesn't feel like grout staining. The grout was smeared over the entire face of the tile so if it was a stain I guess the tile would be consistenly stained.

Is this just moisture that will dry out?

Cheers

 

[Stuart_AC]

Hi all..

Further to my post above the weird wet grout lines were just some staining. I tried to clean it off about 5 days after grouting and it didn't budge then again 10 days (this time with a machine disk cleaner) and it came off.

The tiles had been carefully sealed all over including the edges so not sure what was going on.

 

[Stuart_AC]

I'm now sealing the tiles with the applicable fila products which I'm finding easy to use. However I have some tiles with dark marks/@streaks (about 20 or so tiles out of 180) that won't clean off. I've delayed sealing these as I don't want to seal in a stain. I'm pretty sure this isn't grout staining as I've cleaned them with the disk cleaner and fila detergent. I've also spot cleaned and hand scrubbed one and the mark hasn't budged. I also tried to 'dry' a hidden patch with a heat gun to no avail.

Wondering if this is some sort of moisture/mineral stain from the adhesive that has migrated through the stone from below? I used BAL stone PTB rapid set so thought this wouldn't be an issue.

Any ideas what this is? I've attached a picture of the worst tile.. some are similar and others only have one or two patches.

Thanks for your help in advance..

 

[Bill]

The last photo looks like trapped moisture, judging by the flow it looks like something has dripped/spilt on those tiles without you knowing.

There are some products to help remove things from stone but as this stone is extremely delicate, I would like to promote one without the manufacturer's test.

 

[Bill]

One more point on the grouting, it looks a tad low in the joints and this could lead to problems like - dirt build up, chipping of the edges.

I normally use as stiff a mix as possible for this type of stone/edge as it tends to stand up better in the joint when washing off (so that the sponge doesn't drag too much grout out)

You normally leave grout a lot longer in the joint before washing than you would think but with this stone, it sometimes proves to be a bad idea. Probably should have been thought through better at design stage.......

 

[Stuart_AC]

Thanks for your comments Tom..

There was nothing on site other than buckets of clean water so I'm 100% confident that it's not a spillage. Also as I said it's on about 20 tiles at all through the house so I would have had to spill stuff over and over at different locations. My gut feeling is that it has migrated from under the tile but I have no experience to back this up. Also every so often a tile got particularly messy with adhesive when laying so got quite a soaking when sponging it off. I can't be sure it was those tiles in particular but maybe thats a factor?

I take your point about the grouting... It's actually fine it's just the picture that's taken in really unforgiving light. You'll see that only the left to right grout lines look low but the bottom to top look fine - that's because there's 11m of glass running along this elevation. The low sun at this time of year skims across the surface accentuating even 0.5mm as a shadow. (Annoyingly though the tile on the top right of this picture is the worst on the whole job for lippage).

At the design stage I did consider the 'grimsby double' or 'swiss grouting method' which is to do a second grout pass to completely fill the joint but discouted that for a 2 reasons.. 1st being that grout isn't a wear layer so would erode in high footfall areas, 2nd being that it risks staining the tile doing the second pass.

 

[Bill]

Stuart........ it has nothing to do with the light....the grout joints are low..... Jeesh you don't like critique, do you?

Oh and I also run a photography business so I know all about light.