This isn't strictly a DIY question, but it is building related and there's a lot of knowledge and experience in this group, so I'm hoping you can help.
My basement was very badly "converted" by a builder who failed to put any waterproofing system in place. As a result it is damp. I've looked in to putting it right, which basically involves stripping it all back to bare walls & floor, putting a waterproofing system in and then refitting everything.
A builder who has quoted for the job has offered to show me another conversion he had done, which I have just checked out. It all looked perfectly good, but I was slightly concerned about one thing. Where the gas meter is sited, the waterproof membrane (a plastic sheet with large dimples) wasn't sealed up - that's to say, two pieces met behind the meter, but you could easily pass your fingers between them and touch the brick wall, in contact with the earth, behind.
AIUI, such systems are dependent on a perfect seal and any breaks in that need repair to prevent the system from failing. When I asked the builder he said that the specific spot wasn't a problem and that moisture could still drip behind and gather in the sill etc. This was at about eye-level, if that makes any difference.
Am I being overly-cautious or should I question this point further?