Making best use of hygrometers

stuart45

It's a good idea to check the surface temperature of the bay wall. If it's below the dew point, condensation will start to form on it.

FreeBear

ChasingtheWelshdream said: It is upstairs and furniture is pulled away from the wall and will definitely be insulated as soon as we can, it is damp to touch this morning.

I'm guessing the house was built 1930-40 ?

If it is anything like the houses of that era built round here, the upstairs bay wall is going to be a lightweight construction. Possibly 3x2 studwork with a cement render on the outside and a lath & plaster finish internally. The only thing you can do is to strip off the plaster, insulate between the studwork, and then put more insulation on the inside before plastering. I'd be aiming for 150mm of Celotex/Kingspan in multiple layers.

ChasingtheWelshdream

1910 but spot on, and yes is the plan. 

Windows wide and we are down to 60%, 14.8 degrees so the breeze is helping today.