I own a semi detached house and the dining room has 2 walls which are internal backing onto the lounge at one side and the entrance hall on the other. The other 2 are external, down the side of the house on one side and to the front on the other. The floor is concrete and until about a year ago the room was carpeted. I recently decorated removing the carpet changing it to laminated flooring and installed black damp proof underlay. I am now getting large patches of black damp and the walls and windows are often wet with moisture. The damp occurs particularly behind the dining room dresser and in the corners of the room. I have a marine fish tank in the room that has been there for longer than 5 years but have never had the damp issue until after I had carried out this redecoration, repapered the walls and replaced the carpet with laminated flooring.
I would be very grateful if any advice on what I can do to prevent and treat the damp area and whether I would need to change the flooring as well as the wallpaper

the damp will be coincidental to the flooring not caused by it
moisture condenses on the coldest surfaces in the room
have you changed anything else in since last year like re plastering new concrete flooring leaving doors open more often drying washing round the house more showers or baths with the doors before moisture vented

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