Limestone bathroom tiles

[RichieR]

Hi everyone - grateful for a little advice

We are having a house extensively renovated, and our builders are (so far) doing a decent job. Budget for their part of the work is £90k - this doesn't include boilers, windows, doors, wiring, decoration, so it's a decent-sized project.

They are down to provide tiling for the bathrooms, with tiles supplied by us. We have a load of lovely limestone tiles left over from my parents' new house, which we'd like to use for two bathrooms. The builders are making a bit of a fuss:

1. There is a bit of flex in at least one of the bathroom floors, in a loft conversion that was done rather badly in the 1980s.
2. Laying limestone on a slightly flexible surface is problematic
- at best, requires extra work / expense
- at worst, may be impossible and result in cracking to tiles

My questions are:
1. With skill and careful preparation, should it be possible to lay limestone tiles on a slightly creaky floor, without them cracking? What is required to do this?
2. Given that they priced in for tiling, and given the scale of the project (and we did mention these limestone tiles during the quote process) can I reasonably insist that they get on with it and suck up the cost?

Thanks for any tips!

 

[Richard C]

The builders are making a bit of a fuss:
1. There is a bit of flex in at least one of the bathroom floors, in a loft conversion that was done rather badly in the 1980s.
2. Laying limestone on a slightly flexible surface is problematic
- at best, requires extra work / expense
- at worst, may be impossible and result in cracking to tiles

Your builders are not making "a bit of a fuss", they are entirely correct & giving you good advice; you should heed it! If your floors have any discernable flex in them, the adhesive, grout & even the tiles WILL fail.

My questions are:
1. With skill and careful preparation, should it be possible to lay limestone tiles on a slightly creaky floor, without them cracking? What is required to do this?

No; even the most expensive latex adhesive/grout products laid by the most skilful you can find will not compensate for insufficient floor rigidity; this tiles will fail if the movement/flex exceeds the tiling product limits!

2. Given that they priced in for tiling, and given the scale of the project (and we did mention these limestone tiles during the quote process) can I reasonably insist that they get on with it and suck up the cost?

That’s a difficult one to answer without knowing details of what you asked for & what they included in their detailed quote, assuming you have one; did you ask them to check the suitability of the floors for tiling? Did they survey the floors in question? Did they include a rate for fixing the tiles just as you asked or did it include remedial works/materials as well? If not, you can hardly expect them to pay for it; you should have insisted they include it at the quotation stage! Unless they specifically listed work & materials required for strengthening the floors then I think it’s going to be difficult to insist they pay for it; mutual negotiation is usually the way in such cases! Have they subsequently surveyed the floors & said what additional work & materials will be required?

Builders are not necessarily best suited to giving tiling advice, maybe they have since had input from a professional tiler they have subbed in to carry out the work.

 

[RichieR]

That’s a difficult one to answer without knowing details of what you asked for & what they included in their detailed quote, assuming you have one; did you ask them to check the suitability of the floors for tiling? Did they survey the floors in question? Did they include a rate for fixing the tiles just as you asked or did it include remedial works/materials as well? If not, you can hardly expect them to pay for it; you should have insisted they include it at the quotation stage! Unless they specifically listed work & materials required for strengthening the floors then I think it’s going to be difficult to insist they pay for it; mutual negotiation is usually the way in such cases! Have they subsequently surveyed the floors & said what additional work & materials will be required?

Thanks Richard for your advice, all sounds sensible. Unfortunately I'm a total amateur - to me, a floor is a floor and a tile is a tile. If the floor needs remedial work I would have expected them to tell me and to price for it. However, inevitably this is just one of several variations (in both directions) as we go through the project and generally they are doing a good job. As you say, "mutual negotiation" and a bit of give-and-take are required.

 

[gasbanni]

How would you feel if you ignore their advice and insist they fit the tiles and twelve months down the line they fail ?

Normally you would lay 12mm ply on top of the floor screw it down every 4" and tile on top of it using flexible adhesive and grout,
But really it depends on how much "Bounce" is on the floor.

 

[Richard C]

Normally you would lay 9mm ply on top of the floor screw it down every 4" and tile on top of it using flexible adhesive and grout, But really it depends on how much "Bounce" is on the floor.

Sorry but 9mm ply isn’t thick enough for over boarding. The BS & most adhesive manufacturer recommendations is 15mm WBP but, generally, 12mm is sufficient & is the minimum thickness you should use. Even then, over boarding sometimes isn’t sufficient & additional work is required; it very much depends on the existing flooring material & the joist size/pitch/span. In older houses, the condition can also be critical & to ensure a good tile base it’s often best to replace the floor with 18-25mm WBP, again depending; this also keep the door threshold heights reasonable.

RichieR Depending on what your builder says, if you want to post back with more specific information on what they propose & the materials they intend to use, I will advise.

 

[paul78]

Based on the short story heard so far i would say your builders are reasonable and spot on with advice as mentioned before they could easily tile away get paid and 6-12mth later FAIL. You should be happy about that as its saved you a couple of thousand pounds already!

As rich says did you get anything concrete over the tiling quote because when jobs start even the best tradesmen cant predict what they are going to find once in the middle of a job.

If you havnt anything set in stone i would say its the customers responsibility to pay to rectify the floor as its their house.

 

[RichieR]

RichieR Depending on what your builder says, if you want to post back with more specific information on what they propose & the materials they intend to use, I will advise.

[/quote]

Thanks - will ask them what they envisage. Suppose they went with your suggestion i.e. 12mm overboarding, would very much appreciate any thoughts on cost. Frankly if it comes down to 1 piece of WBP and 3 hours' work, it's not something we'll argue about in the big scheme of things...

The bathroom in question is about 2m x 2.5m, but I'm guessing they wouldn't have to do the area under the bath, so call it 2m x 2m.

 

[RichieR]

As rich says did you get anything concrete over the tiling quote because when jobs start even the best tradesmen cant predict what they are going to find once in the middle of a job.
]

Yup agreed - and even the best customers don't know much about building, that's why we end up with situations like this .

 

[gasbanni]

Normally you would lay 12mm ply on top of the floor screw it down every 4" and tile on top of it using flexible adhesive and grout, But really it depends on how much "Bounce" is on the floor.

Sorry but 9mm ply isn’t thick enough for over boarding. The BS & most adhesive manufacturer recommendations is 15mm WBP but, generally, 12mm is sufficient & is the minimum thickness you should use. Even then, over boarding sometimes isn’t sufficient & additional work is required; it very much depends on the existing flooring material & the joist size/pitch/span. In older houses, the condition can also be critical & to ensure a good tile base it’s often best to replace the floor with 18-25mm WBP, again depending; this also keep the door threshold heights reasonable.

RichieR Depending on what your builder says, if you want to post back with more specific information on what they propose & the materials they intend to use, I will advise.

Odd that ! I have friends who are professional bathroom fitters unknown to each other that dont advertise and work is recommendations or repeat buisness who until the latest recession were booked up nine months in advance both recommend 9mm for reasonably sound floors !

 

[gasbanni]

meant 12mm !

 

[Richard C]

meant 12mm !

You nearly had me going there for a minute

Floor rigidity is paramount & its all about floor construction & condition. You can’t lay down any hard & fast rules but, in most cases, you’re going to be fairly safe with 12mm WBP (except over chipboard) which is already thinner than the minimum 15mm recommended by BS 5385, all the leading adhesive manufacturers I know of & the Tile Association, who are supposed to be the industry experts. Older properties tend to have larger section joists so (in good condition) & in light load/use areas such as bathrooms you might well get away with less but for the sake of 3mm & a few more quid, why risk it, I wouldn’t!

There are many “tilers” who don’t understand/never heard of best practice, don’t understand the materials they are working with, simply just can’t fix tiles or don’t give a stuff anyway; this & other tiling forums are full of posts testament to it! I personally know one joker who does nothing but new build developments & over boards using 6mm ply & sometimes even hardboard but it’s a disaster waiting to happen. Your average makeover job & many new builds may only to last 3-5 years or so (some only last 6 months!) but quality work should last at least 10 years & very much longer in most cases.

 

[gasbanni]

No prob weve just done one in 12mm over a chipboard floor above a garage
absolutely rock solid.

Any idea how to removes limestone deposits through grout lines on a tiled floor ?

 

[Richard C]

Sorry only just spotted your other post, have replied there.