british standards do not usually dictate who is responsible for different parts of a contract and they certainly don't dictate that a particular tradesman e.g. in ths case the tiler, must have the necessary knowledge to do their job.
This particular aspect is dealt with in contract law and I beleive specifically under the provision of goods and services legislation which says that a contractor must have the necessary expertise and skill to carry out a contract correctly otherwise he will be deemed to have been negligent in accepting the contract in the first place.
You are presumably a private householder and as such cannot demonstrate expertise in tiling a floor. Whilst it is reasonable to expect that you would have said to the tiler that you wanted him to
tile your floor. You would nbot be expected to know that there are different types of floor necessarily and that each has its own requirements in terms of preparation.
It is making my blood boil somewhat today because this is one of numerous occasions in the recent few weeks that I have come across tiles delaminating from a screed due to the tiler "not knowing what sort of screed it was". Sorry but this is fundamental to operating a skilled trade. All tilers these days ought to know that there are many types of screed around and each needs to be treated in its own way. Calcium sulphate screeds have been around for a long long time and the information about them is easily available.
I have run numerous training sessions in the last few years, one even for members of this forum, for tilers and I always say that, when a client asks you to
tile a screed, the first question you should ask is not how much are you going to pay me and when can I start but "what type of screed is it"...... It is not a reasonable excuse and would certainly not form a defence in law for a tiler to say "I did not know what sort of screed it was" ..he should know!!! Likewise it would not be a suitable defence for a client to say "I don't know what sort of screed it is either" - if the tiler has asked and you have mis informed him then it is in my opinion your fault, if however he has not asked the question then he should foot the bill.......either way PVA is not a suitable primer for a floor screed to be tiled.
You could get an independent assesment to help you but this would cost more money still but my advice would be to write to your tiler and say that you hold him responsible and that he should come and fix the problem. put some timescales on it and then see what happens. If nothing happens seek legal advice about running it through the small claims court.
The tiling association have a document available called tiling to calcium sulphate screeds which they can no doubt send to you. It is in the process of re writing at the moment and the old document is a little out of date but it still covers the essentials.
