Damp marks on walls

[David Noel]

Hi, I could do with a touch of advice.

My wife and I are wanting to buy our dream house. We've done several viewings, talked to the vendor lots, and we think it really is the perfect house for us. It's a clay lump building, recently been renovated by its owner who is a builder who we know to be very genuine and friendly from other people we know in the village.

However... on our last visit, we spotted something in one of the upstairs bedrooms (top floor). The room has a dormer window, and whilst the vendor has completely renovated the rest of the property we know he hasn't re-roofed it. On two of the (internal!) walls of the bedroom, there are lots of small patches of what looks like damp. We're not sure what it is, is it mildew?

We haven't broached it with the vendor yet - I plan to in a few days time before we actually put an offer on the property - but I'd appreciate any opinions in advance.

I am anticipating needing to look in the loft above the affected room and check for signs of damp rot, but there is no sign of rising damp downstairs, nor anything else unusual. What does the appearance of the spots on only the inside plasterboard walls suggest? There's no sign of this anywhere else in the property, only in one room - so does this suggest it's a leaking roof? What else should I be on the lookout for?

Thanks.


Dave

 

[Doggit]

It looks more like mold than a damp issue. Are they outside walls, and are the windows open or closed.

 

[David Noel]

It looks more like mold than a damp issue. Are they outside walls, and are the windows open or closed.

No, they are internal walls (no sign of it on the external walls). Although I didn't see the windows open I have no reason to think they couldn't open. I'll check them on the next viewing though.

 

[Doggit]

It's not about whether they can or can't open, but are they being kept closed by the current owner, and not letting the moist air in the house escape. A person breathes out half a pint of moisture each day; add in the cooking, drying the clothes etc, and all that moisture has to go somewhere, and if the windows aren't being opened, it'll condense on the walls as mold.

 

[David Noel]

It's not about whether they can or can't open, but are they being kept closed by the current owner, and not letting the moist air in the house escape. A person breathes out half a pint of moisture each day; add in the cooking, drying the clothes etc, and all that moisture has to go somewhere, and if the windows aren't being opened, it'll condense on the walls as mold.

I guess it is a possibility. The vendor is very energy contentious and talks a lot about heating costs, so it could be he never opens the windows. But this is the only room in the house where this is happening.

 

[Doggit]

Then what's different between this room and the others.

 

[David Noel]

It's the master bedroom... it's at the rear of the property... it has an original dormer, but I can't work out how far that dates back. The original building is around 300-400 years old, but the roof I suspect is newer.

 

[Doggit]

Does that bedroom face north, which would make it colder. Is there adequate insulation in the loft. Is the staining on the plasterboarded walls, and there's inadequate insulation behind them.

If you're going to put an offer in on the property, then make the offer, "subject to survey"

 

[David Noel]

It's a south-facing bedroom, no shade on the roof. I'm told there is a huge amount of insulation, in the loft particularly.

 

[Doggit]

Then it's either as simple as not opening the windows, or there's something bigger going on, and I've gone as far as I can.

 

[David Noel]

It's a helpful start, thanks for the tips. I guess at the end of the day, it's a question of what's the biggest "big" possible... I don't particularly mind if I have to re-roof the entire property, as long as I can anticipate it and adjust my offer accordingly.

 

[freddiemercurystwin]

It doesn't look anything like damp caused by a leak, it just looks like mould caused by condensation.

 

[roboughton]

You say its the master bedroom - I think its caused by condensation. Could it be that the loft maybe well insulated but the walls are poorly insulated?

We had it really bad (stone wall house so no insulation and LPG combi that was very expensive to run) we fitted a positive air ventilation system in the loft and this 99% cured the issue.

 

[David Noel]

You say its the master bedroom - I think its caused by condensation. Could it be that the loft maybe well insulated but the walls are poorly insulated?

We had it really bad (stone wall house so no insulation and LPG combi that was very expensive to run) we fitted a positive air ventilation system in the loft and this 99% cured the issue.

That's really helpful, and as you're the second person to suggest it's condensation then I think you're right. I'll look into the insulation on the next viewing and research ventilation.

Thanks very much for the advice!

 

[foxhole]

Seen marks like that when someone tried to paint over greasy walls, if the walls are not prepared correctly they contamination spots thru the emulsion.