Natural Stone Flooring Advice - kitchen problem

[RRout]

Hi, I'm a new user so I hope I'm using the correct forum for this post.

In October I ordered a new kitchen from a firm that does everything: install, electrics, plumbing, units, appliances, granite and tiling. I knew that this would be more expensive than project managing it myself but I've been very unwell and wanted to avoid the associated hassle of arranging everything myself. As part of this package I arranged for a pompadour marble opus flooring to be put down. This portion of the bill alone exceeds £4,000. The firm stated that the natural stone tiles would be put down on something called "no more ply" (forgive me if I've got the exact name wrong). Their in-house tiler visited me today to measure up a further 16 square metre area of my ground floor where I also want the marble put down. Suddenly at after 5pm this evening (3rd December) I had a call from the kitchen firm saying their tiler doesn't want to put down natural stone on my floor as it may not take the weight. Work is due to start on the kitchen on 6th December and the firm is now requesting that I choose an alternative ceramic or porcelain tile. While this is likely to be cheaper, I've already disposed of all the shares required to cover the cost of the kitchen and it may sound odd but I'll now be rather irritated if I have to spend less as I had to suffer some interest penalties to get at the total amount required!

Now that the background is over my query is this: my house was built in 2002 by Hopkins Homes, the kitchen is on the ground floor, I have a "caberboard" (again forgive me if this is the wrong name) suspended floor which is level and has been previously tiled (albeit with ceramics), several of my neighbours with exactly the same specification house and flooring have natural stone floors and, furthermore, two independent tilers quoted for putting down natural stone (having had sight of the caberboard flooring as the previous tiles have been taken up) in my kitchen and were happy to do so before I decided it would be simpler to have it all managed by one firm. Am I just being confronted by an awkward tiler? Is laying marble on caberboard suspended floors really an issue? My neighbours say their tiler put ply over the top of the caberboard so could marble go down if the kitchen firm didn't insist on using "no more ply"?

I'm due to give the kitchen firm a cheque for the total amount (minus a tiny completion amount) for the kitchen install which includes the marble tiles on Monday before they start work and I'm now somewhat reluctant to do so when I don't know where I stand regarding the tiles. Unfortunately they have me against the wall rather as I'm very unlikely to find another tiler who is available the week before Christmas.

Sorry for the lengthy post but any advice would be much appreciated!

 

[doug boardley]

your tiler is right to question the floor integrity (imo), are the joists dimensionally strong enough? are there sufficient "noggins" to combat deflection issues?, did he want to use a de-coupling membrane?

 

[RRout]

The joists seem to be strong enough but I confess I'm no expert - the previously tiled floor has taken a considerable amount of weight in the past including incredibly heavy gym equipment with absolutely no problem (it's an open planned kitchen/dining room). I'm sorry - I've no idea what noggins are let alone deflection issues! In terms of a de-coupling membrane he didn't even offer up any solutions - he simply seems to be refusing to consider laying natural stone. However, one of the previous independent tilers did state he would use some sort of flexible looking rubbery underlay before putting natural stone tiles down. Sorry for the lack of specific technical terms but I'm in no way an expert. To be honest, I don't mind what needs to be done to make the floor ready for natural stone, I'm happy to pay, I'm just wondering if it really is "impossible" and whether they really should have considered this in October when quoting for the work rather than 3 days before the install begins? Thanks for taking the time to reply.

 

[Dan]

It's nice to hear of a cautious tiler every now and again to be fair. We hear of so many 'tilers' just sticking them to anything it's refreshing to see the opposite.

There should be ways of strengthening the floor and the kitchen firm should know this. As Doug says, a de-coupling membrane such as Dural CI and extra noggins in the joists will usually do the job shouldn't it?

 

[doug boardley]

noggins are floor bracers that span between the joists, they help to tie the whole floor together and reduce deflection ("bounce") in your timber floor. The rubbery underlay that a previous tiler hinted at, was in all likliehood, a de-coupling membrane.

 

[RRout]

As the caberboard is already down, I'm guessing it will mean taking up the floor in order to size up the quality of the joists / noggins and strengthen them if necessary? I'd have been happy to do this given I've had two months to get the floor ready but I may struggle in three days! If it helps you to size up the task, I know that there is some sort of polystyrene insulation (behind black plastic?) beneath the caberboard - I can see it where the plumbing comes in.

 

[Ajax123]

Can you speak to Hopkins Homes to get the engineering calcs for the joists. They should have that info available fairly easily. A call to their technical manager or director ought to get you that info. That would save taking the floor up un-necessarily.

 

[RRout]

I wish I could. Apparently Hopkins Homes destroyed the technical plans and engineering calculations for my home and they're no longer available. I asked them for them earlier in the year when trying to establish if an interior wall was load bearing. It was built in 2001/02 so I guess I've just missed out on them - very frustrating.

 

[Ajax123]

Nightmare!

With it being new build it is likely that the joists are engineered rather than solid. It would be unusual for a builder like Hopkins to use solid joists certainly. You need to establish the loading capacity of the floor so you need the size of the joists and the unsupported spans. You can calculate the weight of the existing load i.e. the caberboard and presumably plasterboard underneath. You could establish the size and span by cutting a small hole in the caberboard floor big enough to get a tape measure to measure the depth and a torch and a mirror to look at the unsupported span. If the joists have a manufacturers mark on them e.g. finforrest, boise, eco joist etc then the joist manufacturer would be able to give you advice about the loading capacity.

I assume also that it is a masonry build and not timber frame. If it is timber frame the frame supplier would almost certainly have the frame calcs as I beleive they generally keep them for several years.

 

[RRout]

I've just taken a look at the caberboard, where it meets the plumbing, and it doesn't seem to have any kind of void beneath it - it seems to sit directly on black polythene which covers the insulation. From drilling a couple of little holes just now this seems to be the case across the whole floor. Any idea what I'm dealing with and what can be done to strengthen it? I'd be happy to put a whole new floor in on the ground floor capable of supporting natural stone but I don't fancy my chances of getting it done before Monday!

 

[doug boardley]

it sounds like a dreaded floating floor.....if this is the case, not a good idea at all to tile onto

 

[Ajax123]

Sounds like a floating floor to me. Not generally considered good for tiling to. Certainly not a good idea with natural stone. The pro tilers might be able to give better advice here. Do you have any flexibility in terms of floor height. if so you could take out the caberboard and put a screed in its place.

 

[Ajax123]

Doug clearly types faster than me......

 

[RRout]

If that's the case I guess the only solution would be to replace the floating floor with a decent floor capable of taking tiles? Any idea how big a job this is? It's odd that Hopkins Homes put in floating floors and then allowed us all to spec tiled floors when we purchased them (nearly all of us in the development have them and I haven't heard about any problems). Sounds like they cut a few corners? Wouldn't surprise me judging by some of the other (non floor related) problems I've had.

I'm completely flexible on floor height - especially as I'm doing the whole of the ground floor. Would putting a screed in be a huge task? I'm afraid I've no idea what one is!

 

[doug boardley]

it doesn't surprise me at all, builders are always saying floating floors are okay to tile onto (that's because they know no different), very few tilers with a decent knowledge of the trade would tile a floater.