im just starting to do up my new house which is 1970s ish with big windows and waffer thin cavity, no central heating either right now and there is mold spots everywhere and under some of the upstairs windows too from condensation and puddles on sills. doing a room at a time and fitted trickle vents to the old but solid double glazing and pretty much cured all the condensation in the rooms iv done it... got some cheap oil heaters too so the house is warming up some , its the back of the house that is suffering slightly more, being east facing and overlooked, loosing the sun by 10ish AM in places, its cold and once wet(rain) stays damp etc for ages, kitchen tiles ringing wet after some cooking and bathroom tiles the same....
previous owners have drilled and fitted insulated plasterboard to the external walls to help with insulation but iv noticed dots all over the walls of late and guessing he drilled straight into the wall and cold is coming through and travling up through the fixing, leaving mold dots spaced out all over lol not sure how im gunna fix this yet...
im fitting rads and central heating piping as i do each room too, plus fitting the trickle vents so hoping once there is warmth and venting shoould cure most of my problems here....