How long before slabs become loose?

Any approved paving installers should give a 5 year guarantee here at birch green paving we are willing to help

Doesn't sound right to me and there could be a few issues: - pointing not sufficient allowing for frost to 'pop' the slabs up from their beds; - problem with the mortar (bed) mix when laying; - no primer or adhesive used (specifically limestone or porcelain paving); - unstable sub-layer. Whatever the problem, unless they have given you a guarantee that has since lapsed, they are liable for the patio for life - 25yrs I think? As always, try to approach the problem amicably at first; we all make mistakes. What's important is that its then put right. All the best Dan

I would of put at least 10 year guarantee on that if done correctly.

It would depend on their method of installation, if done properly on a full bed it shouldn't come loose for a long time if at all, but if they have used a dot and dab method where they put a blob of mix in each corner and one in the middle then this isn't really sufficient and can lead to these problems. I'd get them back to give them a chance to rectify the problem as any normal person would want the chance to do.