I live in an old building but my flat was completely upgraded inside when we bought it. Everything is new from floors to bathroom and kitchen etc. There is a strange eggy sometimes gassy smell coming from the kitchen it happens about once every day or two for only about 5 minutes. The place is immaculate there is nothing dirty in there. The smell seems to be coming out from under a skirting board strangely near the radiator I think. We are two flats up any ideas what it could be or how to solve it? I had thought it may be something to do with a pipe of some kind but it is nowhere near the plumbing.

Smells like a gas leak. Don't light a match!