Damp spots and independent gurus...

[jca]

Hi Folks,

I have a damp spot the middle of a ground floor party wall of our 1890's terrace. The damp patch has a discrete outline, and starts at skirting board level rising to about 30 cm up the wall. Having done a little reading round on damp, I suspect this is not due to the most common causes of blocked drains or plumbing (there are none around this area of the property) or leakage (it's in the middle of the wall, a good 3 feet from the exterior of the property, with no sign of leakage around the roof, or damp in the room above). When we moved in last year, I thought there was a trace of a damp spot in this area, but found the air bricks at the front of the property were obstructed, so cleared them and hoped it would go away. I think in this time it has actually got worse, however. This house does seem to have been subject to minor movement, which I suspect may have fractured what I assume to be a slate DPC. Does this sound like the most likely cause, and if so, is it necessary to have a chemical DPC treatment to the entire house, or can just the affected area be treated, given there are no problems elsewhere? I'm really trying to get an idea of the probable cause so that when I get someone in to look at it, I have a vague idea if they are trying to pull a fast-one or not.

On that topic, I'm trying to find someone to take a look at it,and understand that most damp treatment companies are affiliated with particular treatments they will try to sell you regardless of their suitability. I would therefore prefer to find an independant specialist who will give sensible advice on what realistically needs doing.

The question is, how can I go about identifying independent specialists from the yellow pages, since in most cases the ads don't seem to mention affiliations with treatment firms etc? Am I best just choosing someone who is a member of the BWPDA and hoping for the best? Take it as read that I don't know anyone in the area who has had damp work done, so can't go by word of mouth!

Thanks,
James

 

[PC]

Where are you located?

There are some independent damp surveyors advertising under SEEKING SPECIALISTS.



PC

 

[NT]

quote="jca"

> I have a damp spot the middle of a ground floor party wall of our 1890's terrace.

> This house does seem to have been subject to minor movement, which I suspect may have fractured what I assume to be a slate DPC. Does this sound like the most likely cause, and if so, is it necessary to have a chemical DPC treatment to the entire house, or can just the affected area be treated, given there are no problems elsewhere?

This is probably the most unlikely cause of damp patches.



> The question is, how can I go about identifying independent specialists from the yellow pages,

you cant, the info isnt there.

TBH you wont need a damp guru if you learn what are the possilbe causes of damp and how to identify and treat them. Its not difficult, it just seems daunting when you dont know where to start. Much like anything does.


NT

 

[Gareth Hughes]

Just a wild stab in the dark, but it's not the result of an uncapped chimney with inadequate ventilation, is it? I've got the same problem in my 1880 terrace.

 

[Lime]

Another stab in the dark.
Does the neighbour on the other side of the party wall have central heating?
I have known leaking radiators/valves to cause damp patches as described on the other side of the wall.

 

[PC]

Firstly not all damp proofing companies will try and flog you :twisted: something dispite what is continually dribbled out on this site. You can find independent surveyors on the BWPDA web site and also on this site as mentioned above.

With regard to your problem - are the ground floors solid or timber suspened?

Is the wall damp to the touch?

Is it papered or emulsion and what is the plaster (original lime or modern cement.

Look forward to hearing from you!

PC

 

[Penners]

While we're having a stab-in-the-dark fest, is there any possibility that some sort of roof problem might be the cause? Even if your roof is good, are you sure that your neighbour's is?

Water can be a real blighter - it can trickle along ledges, rafters etc. and eventually appear a considerable distance away from where it first enters the building.

 

[NT]

Firstly not all damp proofing companies will try and flog you :twisted: something dispite what is continually dribbled out on this site.

Not always no, but nearly all wont make a living if they dont sell such treatments, so the temptation is obvious and the customer should beware.


NT

 

[biffvernon]

Congratulations, NT, on the successful deployment of a quotation (even if the embedded emoticon didn't work )

 

[PC]

NT wrote
Not always no, but nearly all wont make a living if they dont sell such treatments, so the temptation is obvious and the customer should beware.

I am not doubting what you say, as an independent I come across these companies every day!

But as I have said many times before on this site... there are also many who WILL give you good sound advice....... and there are those....... who would sale you a chemical damp proof course as a cure for the common cold!

PC

 

[Moo]

But (isn't there always a 'but'?) how does one tell the difference?

 

[Geoffrey]

When I last moved I had a damp survey done by someone I think I found under the seeking specialists part of this site. All he did was a survey and didn't try to sell anything. We discussed what I planned to do gradually to try to cure the damp and it did give me peace of mind that someone who dealt with it all the time was able to confirm some of my ideas and push me in the right directions. It was quite expensive as I remember (but did involve travelling as they were not particularly local) but a lot less than any spurious treatments would cost.

 

[PC]

Geoffrey,

I think you have hit the nail on the head. All independents charge for their time and most people don't want to pay! They want it for FREE. If you get a free survey you normally end up PAYING and usually for unnecessary treatments.

On an average week I probably get 3-4 calls from people who want a survey or advice, but when you mention a fee the normal response is......... "Oh I thought you did free surveys - I'll get back to you", and most never to be heard from again. Some however do come back, but normally when they've just opened their post and found a quote for £5,000.

PC

 

[Moo]

Children should not be allowed to leave school until they have learned by heart (and really understood the meaning of) "There's no such thing as a free lunch".

 

[bournonite]

Umm..

Should I go into detail here about condensation versus so called rising damp - and lovely things like carbide tests that send the so called pros running for cover? That chimney sounds like condensation to me - especially if there is a chance there may be a few salts buried within. (Refer the other poster who mentioned blocked chimneys etc..) Is the room well ventilated? Ie, vented windows, vented chimney, not heavily heated etc....? If you could find an independent surveyor who can do a carbide test - by that virtue alone you'll have found someone who really knows about damp...

Pete

 

[Penners]

Pete - yes, please do go into a bit of detail. What's a carbide test? (Presumably nothing to do with ancient car headlights!)

 

[bournonite]

Indeed - it has everything to do with headlights...

As I said, most damp problems are caused by condensation - so to check for the real rising damp, if such a thing exists, which I guess is theoretically possible if the old boys left out the slate or something, the surveyor gets out his carbide kit.

Basically he drills through the plaster (about a 10 mm hole will do) until he gets to brick or stone. At that point he takes a sample of the cuttings - holds a little dish under the drill and bores right into the brick.

He then takes a known weight of calcium carbide, and weighs the cuttings. They are then put into a chamber which looks for all the world like an old car headlamp. The water in the cuttings reacts with the carbide when they are shaken together for about 5 mins. Acetylene is released, which is allowed to fume off. The resulting 'ash' is then weighed again. The loss of weight is due to moisture content, which is then back-calculated to a % moisture figure.

In all the carbide tests I've witnessed in damp houses, not one of them has shown damp in the brick, even though sometimes the walls are wringing wet. Its nearly always condensation in the plaster which dries out once the environmental factors are sorted out (acrylic paint, ventilation in the room, etc)


:wink:

 

[Nemesis]

http://www.ridoutassociates.co.uk/services.htm

and from the past...

http://www.periodproperty.co.uk/cgi-bin/discussing/forum2.pl?noframes;read=64681

 

[Geoffrey]

Bournonite - well maybe theortically...

I do actually have rising damp. It's damp and it rises through the walls on my ground floor. I have taken several steps to improve it, and hopefully over time it will be naturally controlled as it's causes are found and eliminated. It is improving gradually (touches wood) - but it is damp and it does come from the ground.

 

[biffvernon]

Not arguing, but how can you be sure that the water is coming up from the ground?