Black Spot Mould

justmyself

I have a house that hasn't been lived in for 20 years.

I stopped running the dehumidifier last year (maybe 2 years now) as the electric bill was running up.

I now have some black spots, guessing mould around my house. I'm presuming this is caused by condensation?





What's your advice folks? How best to fix? Are these 2 steps enough?

1) Treat it chemically with a mould eradication kit? Any brand/ solution recommended? Or step by step that should be taken?

2) Look into ventilation to assist in the lowering of humidity levels within property? Would drilling a hole in various walls suffice?

Any advice greatly appreciated.

Calahonda52

Need a bit more intel on the house:
what type?
whats above the ceiling?
any other ceilings the same?
What size is the room?
what direction are the being joists running?
What ventilation is there already in walls?
Any central heating pipes in ceiling?
etc
etc

ps: I don't subscribe to the mould eradication route until you are 100% certain of cause and solution

justmyself

Thanks for the reply Calahonda52.


What type? It's a 3 storey House. That photo is of the middle floors ceiling. The lower ceiling seems fine (although it has ceiling boards in certain rooms, so maybe hidden). Lower floor has concrete flooring. The house dates from 1880's... maybe earlier.

Whats above the ceiling? Another floor level (the top floor). With 2 Rooms, but no pluming or heating.

Any other ceilings the same? Yes, similar black spots on the upper floor ceiling. But not in the same spot directly above - it's on the slanted ceiling above the stairs.

What size is the room? 250 ft

What direction are the being joists running? The floorboards are running top to bottom in that pic. So i'm assuming the joists right to left.

What ventilation is there already in walls? There's ZERO ventilation. Other than fireplaces, windows and doors.

Any central heating pipes in ceiling? There is no heating in the house at all. Just fireplaces.

justmyself

THE UPPER FLOOR



Lower floor has boards on the ceiling


Most of the ceilings look like this. Slight discolouring. Guessing due to no ventilation?

justmyself

The fact that the house hasn't been lived in for 20 years... or painted. I wonder could it just be thermal tracking or "ghosting" ? The sooty or dark lines or stains appearing in patterns on building ceilings or walls on the inside of buildings, especially in older homes whose interiors have not been re-painted or cleaned in some time.

Reading up i saw this:

Thermal tracking or ghosting stains usually map the location of cooler surfaces such as the locations of ceiling joists, wall studs,or areas of smaller amounts of or completely missing building insulation.

Note those dark "stripes" extending along the ceiling? These ceiling stains probably mark the location of ceiling joists (where the in-room ceiling surface temperature was kept a bit cooler since these locations in the ceiling cavity are occupied by a wood joist rather than by insulation).


If so. Do i clean with a product and simply repaint?