rising damp. leak or condensation?

[Anonymous]

I have a victorian terraced house with a 1m high triangular shaped tidemark on the wall, up in the corner of my living room, and showing through the other side of the wall in the hallway with flaking plaster/paint at skirting board level. There is salt residue on the wall but no mould and the damp reading for the wall is high. The problem has gotten neither better nor worse in the past four years, it just shows through any new paintwork but does not grow laterally or vertically. We have had many 'experts' in to try to diagnose the problem and are getting conflicting answers each time. Nobody can tell me anything that I don't already know: namely that it is either rising damp, a leaking pipe in the wall or condensation. Does anyone out there have any tips for narrowing down possible causes as I am reluctant to have a chem dpc or other invasive and expensive work done without first finding a clear identifiable problem. Any advice gratefully received...

 

[Anonymous]

"Does anyone out there have any tips for narrowing down possible causes as I am reluctant to have a chem dpc or other invasive and expensive work done without first finding a clear identifiable problem."

Unfortunately without a bit of destructive work, you won't know definitively what the problem is.

Mould will only grow where there's fresh water. No mould growth in 4 years suggests to me this is not a condensation problem. Salts in ground water moving through the wall will inhibit mould growth.

At this point you need to go through teh PPUK achives and run through all the rising damp checks:

ground levels
render in ground contact
guttering leaks
drainage

All the usual stuff that gets rolled out.

If everything stills seems fine get an independant damp surveyor to remove masonry samples from the wall and put them through a calcium carbide meter or the oven/dry process to see how damp the walls are, the pattern of water movement within the wall and provide some recommendations from there.

Some or all of that should help.

Matt Green

 

[Anonymous]

Is there near your main supply pipe into the house?

 

[Anonymous]

Thanks Matt, that should certainly get me started. I think rising damp is most likely but what throws me is the fact that the tidemark is so well-contained to a single spot and does not extend sideways. A bit of desctrutive investigation seems to be called for....

thanks again

Laura

 

[Anonymous]

Hi Peter: yes the mains water pipe runs under the floor in the corridor adjacent to the wall in question. However we have had a plumber in, who ripped up three separate sections of flooring and made a big whole in the kitchen concrete floor and found absolutely no signs of water/leakage.... the radiator pipe however enters the base of the wall/skirting pretty much at the base of the stain which could suggest a leak however no loss of pressure on the boiler has been detected.... the plot thickens.

 

[Anonymous]

Laura, I have a thought about your "tidemark", but it depends how its triangular shape is orientated. Is the "base" (ie: the widest part) of the triangle at the top or the bottom (or neither)?

 

[Anonymous]

Hi David. The widest part is at the bottom and it culminates into a peak. I am attempting to attach a photo. The main characteristic of the water stain is that it is very patchy...

 

[Anonymous]

That skirting board looks rather modern.

 

[Anonymous]

Laura,

If you would like to post me a sample then I can run a full moisture and soluble salt analyses on it - no charge. Should perhaps give a clue as to the origin.

It certainly isn't consistent with surface condensation from its appearance.

PS Don't tell the others - I am persona non gratis on this forum!!

GRC

 

[Anonymous]

meaning? can tell you its minimum 6 years old.

 

[Anonymous]

thanks grc, but wouldn't know the first thing about getting a good sample. would this mean drilling holes and putting samples in airtight containers?

very generous offer though.... can i ask without causing offence what's in it for you? <IMG SRC="http://www.periodproperty.co.uk/discussing/smileys/wink.gif" BORDER=0 ALT="">

 

[Anonymous]

"can i ask without causing offence what's in it for you?"

Probably nothing but a warm fuzzy feeling inside.

Damp surveys are like a good whodunnit novel. There's a certain amount of satifactioon in finding the anwser.

Matt Green

 

[Anonymous]

true but unlike a good whodunnit novel they don't cost £4.99 and there's no guarantee the plot will resolve...

 

[Anonymous]

6 years old?
On this site that's uber-modern.

So - sometime in the last decade someone felt the need to rip off the old skirting boards and replace them. They probably replaced quite an acreage of the original plaster as well.
I'm not saying that's the cause of your damp - just that it may be significant.

 

[Anonymous]

Hi moo. I tend to agree its a pretty big clue but then its not the only one - there are others such as plastic sheeting under the floors etc... But then given that the previous owner and his builders were all cowboys, who's to say they did a good job of it. Me thinks they tried to cover up and not to find the problem so I still have hope that we can find a long term solution....

 

[Anonymous]

Well if you will use such questionable Latin what can you expect Graham?

Tut.

The Edants will be livid.

 

[Anonymous]

"Livid" may be something of an overstatement, Madam, but I confess to a slightly flushed appearance about the cheekbones. I suspect that a rather cheeky pinot gris may be to blame.

As you have observed, it is something of a contradiction in terms for someone to offer a service free-of-charge and then describe themselves as "persona non gratis".

A hint at hidden charges to come, perhaps?

 

[Anonymous]

Hi Laura. The picture is a big help - and the fact that the triangular mark goes around two walls blows my theory out of the water!
The radiator pipe is interesting - do you know where it runs before emerging from the floor?

 

[Anonymous]

Would you take sweets from a stranger? The man is offering you something for free. Therefore he MUST be some kind of perv. Check the link out below - ALWAYS be suspicious of altruism. Everyone offering "help" is just trying to boost their ego, rip you off, or desiring sexual favours. Run away from your computer and never come back. The internet is a dangerous place. You are not safe here.


http://en.wikipedia.org/wiki/Friedrich_Nietzsche

 

[Anonymous]

unfortunately I have no idea where the pipe runs and without bashing the wall in...... There is a good chance it runs up that wall though, possibly even up the corner, as the boiler is almost directly above on the first floor, but I would have a assumed that a leak which can cause that much damp would show up on the pressure gage on the boiler? or am I misguided?