Damp?

mel.b

I've recently bought a house, built in 2006 and have been in it for a month now. The house originally had a small front porch area, however the previous owners enclosed it with a door and two small windows on the side walls. There are tiles on the floor and the ceiling is red deal pine. The walls are rendered brickwork with no plasterboard over it. The area outside is concreted and tarmac. Directly above this area is the master bedroom.

When i first got the keys, i noticed that this area smelt a bit funny, however as they had had a large shoe box, coats etc in there as well as leaving beind some funny looking ornaments i thought that that may be what the smell was from. I aired it all and as the painters were in, the front door was open for a good few days in the sunny sept weather we had and the smell went. However over the past few days it has been coming back and it really smells in there now. I think it might be damp as it does smell a bit like a wet towel that has been left in a bag :eek: Or could it simply be a lack of airflow and stale air in a small area?

Any suggestions in what to look for and what i could do to fix it? Is it most likely to be damp or something else?