Condensation or damp

[ashirusnw]

We've got a first floor flat with some mould appearing just above the skirting. The tenant claims that it must be penetrating damp coming through the brickwork somehow - perhaps poor pointing.

I can't see anything wrong with the brickwork except for a few pockmarks but I'm not certain it's merely condensation at this point.

See photos of the damp/mould marks and brickwork on the outside.

What do you think?

thanks,
Ash

 

[EFLImpudence]

Well, we can't tell from here, BUT

tenants always blame 'damp' for the condensation they cause by not heating AND ventilating the premises enough and very rarely clean it.
They seem to think the landlord should do the cleaning.

Tell them to wipe it with neat bleach.


How long did that take to form?

 

[blup]

Looks like surface mildew, does it wipe off with a warm damp cloth? Can be made worse if the wall is north facing or doesn't otherwise get the sun - or if the room is not sufficiently heated.

Can't say whether there is penetrating damp, but same comments apply as above, especially if there has been a leaking gutter or roof from which rain has over the years penetrated a particular post on the external wall.

If you're letting, doubtless your agent will be able to recommend a suitable surveyor to take a look.

Cheers,

Blup

 

[KenGMac]

ashirusnw, good evening.

By any chance is the external wall retro-filled with cavity insulation?

Ken

 

[ashirusnw]

ashirusnw, good evening.

By any chance is the external wall retro-filled with cavity insulation?

Ken

It's an uninsulated 9 inch solid brick wall

 

[ashirusnw]

The marks do only appear above the skirting and come off with some bleach.

 

[KenGMac]

ashirusnw, good evening again.

Is this problem a recent occurrence or? has it been on-going for some time?

Externally are there any obvious defects in the brickwork.

Sorry but more questions and so far no answers, it is a process of elimination.

Solid walls can / do allow rain water to penetrate, if the problem is of long standing could be an area of the external wall is in need of attention, re-pointing Etc.

As a general question how many people live in the property? has someone else taken up residence recently? [Increased free water in the air?]

In which room does this problem manifest itself? is it a Bedroom? is the room north facing?

Ken

 

[blup]

The marks do only appear above the skirting and come off with some bleach.

That's your problem solved by the sound of it, but mildew will come back if the underlying conditions remain e.g. cold unheated/unventilated room.

Blup

 

[JohnD]

Is it a concrete floor?

Are the signs of damp equal all round the room? Or just on the external walls? Or, for example, under a window or close to a radiator pipe?

Or close to a gutter downpipe?

 

[EFLImpudence]

And - Is there usually furniture against the wall?

 

[noseall]

Its plain old cold-bridge related condensation mould. The wall needs insulating, simple.

 

[motorbiking]

I have the same issue on one of my 9inch walls. Noseall is right in my view. I’ve been gradually taking mine back to brick and adding celotex and plasterboard, makes a big difference.

might not be cost effective for a rental though.

 

[blup]

Condensation happens when warm moist air meets a cold surface, and the mould is a warning that heating insulation or ventilation require attention.

The introduction of appropriate insulation should resolve the issue (assuming there is no external penetrating damp). But surely it would make sense (and be more cost effective) to address the heating and ventilation issues first e.g. reducing the source of moist air such as an adjoining kitchen or bathroom, or even wet clothes being hung out to dry on radiators (think how much water is produce when tumble drying towels).

Blup

 

[noseall]

reducing the source of moist air

You could always ask the occupants to stop breathing out, too.

Shmuck (not my real name).

 

[blup]

Yours is a builder's solution, mine is from a DIY perspective, being one doesn't rule out the other.

Blup