Condensation spot in newly insulated conservatory

SophiaBC

Good morning,

We had our conservatory insulated by a professional and well recommended company last week. Essentially they place a reflective film on the glass, and then cover with foil insulation, board over and plaster. We waited for this to dry out and then had it decorated.

The problem we are having - which we had never noticed prior to the work - is that there is a ‘damp’ patch forming every night in a circular pattern around the existing supporting internal pole - not sure if this is decorative or actually supportive. It seems to dry out in the day and then reappear overnight. This started happening prior to the decoration and seems unaffected by rain, so I don’t think it’s a leak.

Since the plaster dried we have had a dehumidifier going and are starting to use a small heater to heat at various times of the day. The dehumidifier alone doesn’t seem to have solved.

Any ideas or suggestions?

SophiaBC

Ps I have a picture but can’t seem to figure out how to post it

Aylesbury_Duck

Pictures would help but it sounds like you have a cold spot on the support pole where moisture is condensing and then soaking into the plaster. I have no idea how your contractor has done the work but if the pole is metal and they haven't insulated it above or around the ceiling, moisture will condense on it. If that's the case, the plasterboard needs removing around it and the pole and any brackets it's connected to need insulating.

SophiaBC

Thank you so much for coming back to me.

I have tried posting a picture but as a new user I’m not allowed to include links.

What you’re saying makes sense - it’s just odd that it’s only on the vertical pole and not on either end of the horizontal.

I will check with the company we used, hopefully it’s something they’ve come across before.

Aylesbury_Duck

Moisture will condense on cold surfaces and its possible that the vertical pole, being metal and in contact with what at this time of year is a very cold floor, is much colder than the horizontal poles which run through air that is perhaps warmer, being at the top of the roof.

ColinFishwick

Yeah sounds like you got some sort of cold bridge, metal especially almuinium often forms condensation unless it has some sort of insulation between the metal and inside.

diamond_dave

Had a similar problem many years ago with cold bridging with dg in bay windows. The square alloy posts joining the windows meant inside there was always a bead of condensation on a cold day. Only solution was to cover the the corner angle with a upvc bead. Not ideal but it worked.