Robert Merry is an independent stone consultant and project manager who ran his own company for 17 years. He also acts as an expert witness. Here he presents his view of the stone industry this month.
In my other life as an expert witness, as opposed to my life as a project manager, I am often asked to adjudicate on the difference between a sample provided to the client at the pre-order stage and the installed material. No other sample has been offered and the client is unhappy with the finished product because it doesn’t look like the sample.
Labels are usually attached to these samples pointing out that stone is a ‘natural’ product subject to ‘natural’ variations. Samples are mostly 100mm square and the label is often bigger than the piece of stone.
These samples are fine as being ‘indicative’ of the stone and for initial selection purposes. They are a good size if posting and easy to carry to site. But they should never be used as control or reference samples.
Range samples need to do what they say – show the range of the material and act as an accepted control or reference to compare to the finished product. They need to be of a good size to show all the variations in the material, so a frank discussion can take place with the client about what is acceptable, what is possible, and what are the cost implications of a finer selection.
Why should you do this when it’s only for a small item, with a relatively low value? Well, because it’s best practice, it will avoid the sort of disputes I am regularly asked to get involved in and because you need to act within the law.
There are several levels of clear direction from august bodies, both internal and external to the stone industry, which set out the obligations of the supplier.
The Stone Federation publishes excellent guides, including Selecting the Correct Stone, Code of Practice for the design and installation of internal flooring, and Code of Practice for the design and installation of kitchen worktops. They are worded so they follow closely the guidelines set out in our industry-relevant British Standards. For those of you still unsure as to the applicable ones, they are as follows (in abbreviated form):
l BS EN 12057 – Modular tiles
l 12058 – Slabs for floors and stairs
l 1469 Slabs for cladding
l 1341 External Paving; 1342 setts
l 1343 kerbs
l 771-6 masonry units – all further titled Requirements.
These are now harmonised European standards, incorporated into building regulations in this country and therefore enforceable by the trading standards authority, should you need any further persuasion.
Basically, the common wording is (paraphrased): A reference sample shall be an adequate number of pieces of natural stone of sufficient size to indicate the general appearance of the finished work… and shall indicate the range of appearance regarding the colouring, the vein pattern, the physical structure and the surface finish… In particular the reference sample shall show specific characteristics of the stone, such as typical holes, glass seams, spots and crystalline veins.
And here’s the important bit: All the characteristics as shown by the reference sample shall be considered typical of the stone and not as flaws, therefore they shall not become a reason for rejection, unless their concentration becomes excessive and the typical character of the stone is lost.
In other words, if you have presented samples showing the full range of the expected variation in the material, then the client will have no reason for rejecting the stone and hopefully you can sleep better at night.
The Standards go further and offer a diagram, which I have dubbed ‘the man with the x-ray eyes’, showing the samples, distances to view them from and the natural light position.
If none of the above convinces you that providing one poorly labelled sample is inadequate and also likely to cause you serious financial pain at some point in the supply and installation process, then there is another juicy bit of law to help you across the line – The Sale of Goods Act 1979. It deals with sale by sample, sale by description, and fitness for purpose. But best not let it get that far.
There is one other criteria upon which the supply of stone is held to account set out in the harmonised standards – CE Marking and Declarations of performance. But more of them another time.
For now, for the sake of making my other life simpler, get the first bit right and show customers samples of the full range of what they can expect from a stone.