Condensation running down bedroom walls and on windows

philboy

Hi,
I'm currently living in a 2 bed, 2 storey flat built onto the side of my mother's house. The house itself is built in the early 80s with the flat extension built in 97. The front of the house which is south facing is built with red-brick and the rest of the house consists of plastered blockwork which has been painted several times.

Two years ago, the house & flat were pumped with internal bead insulation and both attics had extra insulation put in. The problem is, my mother's house is always warm when the OFCH is on but our flat has been consistenly cold during this cold spell of the last 2 months or so. The external walls in my mothers house don't feel particularly cold yet when I touch the walls in my flat, they're freezing in comparison. The house heats up quite quickly but the flat takes ages. I've measured the radiators using an online calculator and they seem fine for the room size.

The main problem is within 20 mins of the heat going off, the bedrooms in the flat are both freezing. There are no vents and they've been insulated as I've mentioned before. This morning I woke up with water runs on the main bedroom walls (south facing + external red brick) & as usual the windows were full of condensation with water resting on the sills.

I'd like to put in vents to possibly solve/reduce the condensation but it's already freezing 20 mins after the heat goes off.

I also have reflective material to reflect the radiator heat back into the room but no point installing that yet if the condensation will just cause it to peel off again.

Has anyone any suggestions?

Cheers

mitosis

Ventilation for condensation. Insulation for heat retention - check the roof particularly.

stephendevlin

Quite possible a leak somewhere

philboy

mitosis wrote: »

Ventilation for condensation. Insulation for heat retention - check the roof particularly.

I understand the need for ventilation for the condensation (it's freezing before I've even added them in) In relation to insulation, the attic already has 300mm insulation and the cavity walls have been pumped. The roof had a partial replacement last year and there are no leaks or condensation up there.

philboy

stephendevlin wrote: »

Quite possible a leak somewhere

I don't think there's a leak in the roof at all, I've been up there twice in as many months and haven't noticed anything. I'll double check this evening or when it's raining next.

I'm wondering might it be the red brick on the front of the flat since red brick is porous. We never painted over this with any sort of sealant.

What I can't understand is; how come my mother's area of the house retains heat, yet the flat which is newer and insulated to the same standard can't.

stephendevlin

philboy wrote: »

I'm wondering might it be the red brick on the front of the flat since red brick is porous. We never painted over this with any sort of sealant.

Quite possible too is there sufficient guttering around the walls?

philboy

stephendevlin wrote: »

Quite possible too is there sufficient guttering around the walls?

We replaced all of the guttering Stephen with new guttering. We're on the coast, so we generally get driving rain that would drive into the side of the bedroom where the brick is. Also the brick on the front of the bedroom would be getting hit directly with rain a lot of the time also. It's on these two sides where I found condensation running down the walls.