Tar smell in new build house

[MTB58]

Hi, I wonder if anyone can help? My new build house is 17 months old and at times there seems to be a smell of tar in the house. this was particulary noticable when w ehad the central heating on all day in the extended period of cold weather. There have been suggestions that this could eminate from some sort of lining in the walls of the house - timber frame with brick and roughcast exterior. Any ideas and/or solutions?

Many thanks.

[collectors]

If its underfloor heating or the pipes are in a concrete floor, it might be the bituminous tar that is sometimes painted on the floor for damp proofing.