Black spots on ceiling

joebloggs123

Hi Guys

Hoping you can help me with an issue we have with a rental property.
Black spots are developing on the ceiling in two of the rooms along the external wall of the house. The area where the black spots occur are also quite wet. The moisture appears to be in three circular areas but nowhere else on the ceiling.
In the other room, they occur tight to the external wall (but not on the external wall) in small patches along the whole wall. I've attached a photos of one of the areas.

Both areas also have windows in the external walls which have quite a lot of condensation on the inside. This condensation has occurred a number of times over the last year or so but it's only now that the black spots are appearing.

Any ideas on what might be wrong and the best way to treat this?

MicktheMan

You have mould forming as a result of:
1. Inadequate heating,
or
2. Inapproprite ventilation,
or
3. excessive moisture load
or
a combination of 1,2&3

resulting in enough moisture available on a continuous basis to support the mould organism. You probably also have missing or disturbed insulation directly above the affected ceiling areas.

Metric Tensor

Some sort of leak or else cold bridging (which is a poor insulation issue coupled with condensation).

We'd need a bit more info ... what's directly above this ceiling and can you show us a picture of the outside of the building next to where these spots are located inside.

tradesman

I worked on an old house and the felt under the tiles had perished. This was letting some rain in behind the fascia & seeping into the house. This could be the cause

joebloggs123

The roof is directly above the ceiling. This particular area is at the external wall so where the roof slopes down to meet the wall and makes it very difficult to access. I'll try and get more photos if I can. This isn't the actual house but is a photo similar to the roof http://www.dbdconsultants.co.uk/wp-content/uploads/2015/03/Original.jpg

beauf

Doesn't look like a leak. More of a damp/condensation issue I would guess.

joebloggs123

How do we prevent condensation on the inside of the house?

Metric Tensor

Open windows more, won't dry clothes in the house, extract fans on when you are showering and cooking ...

... small sensible changes can make a big difference.

joebloggs123

All of those things are being done. We could open the windows more but it's quite cold at the moment

B-D-P--

On a note to remove the already there mould,

dabbing bleach is very good at killing the fungus.