We have a new build (finished 10 months ago) and the house is grey block with "Kingspan" type insulation on the roof and walls and finished with plasterboard - therefore I assume no cavity. Recently we have been troubled by a terrible scratching sound coming from our bedroom walls - if you put your ear to the wall it sounds as though the creature is munching! We think the only place anything could get into the house would be via the roof tiles but how would they be getting into the wall itself? We purchased some mouse and rat traps and put them around the outside of the house and placed some poison in dishes aswell but because we don't actualy have a roof space over this part of the house (the beams go right up to the roof itself) it is difficult to know where else to place them. So far we have caught nothing but the awful noise continues. Is it likely to be a mouse or a rat? We have quite a few lizards in the garden but not sure if they are classed as pests? Any advice would be much appreciated.