Three conflicting quotes on damp problem

[Shytalkz]

I take your point, to an extent, but, if you're looking for a Tudor manor, say, then it's axiomatic that you're going to know beforehand that it's not going to be very thermally efficient.

I'm sure that there must be some corduroy-wearing tree huggers out there for whom energy costs for the building are going to be the overriding consideration, but in that instance, they are going to be looking towards more modern buildings to satisfy their requirements anyway.

As a separate point, it would be interesting to learn precisely how many professionals in the construction industry have actually bothered with the HI Diploma...

 

[^woody^]

So, "Location, Location, Location" is no longer the mantra of choice and has been replaced by "Insulation, Insulation, Insulation"

I don't know anyone who has, or will buy a house depending on energy ratings, and its merely a curious and insignificant little sentence in the selling pack.

Is any woman going to pick an insulated roof over an integrated kitchen? Would their husband prefer insulated walls or somewhere safe for his BMW overnight?

Energy ratings are a political fad with little or no value in 'real life'

Just see how many numpties will buy a top rated house "to do their bit" and then fire up the patio heater for the summer bbq's!

 

[Shytalkz]

Well said

 

[and1c]

Wow.
The original poster has certainly got some excellent advice in this post

Collective 'real world' experience of XXX years counts for FAR more than a Damp proof salesmans word...

 

[JerryM]

Do you have any advice on what the surveyors say and what we should do next

to sort damp you need to find the cause. this needs measurements taking and visual inspection. it's not easy to do (get it right) and it does not surprise me at all that 3 "inspections" have resulted in completely inconsistent results.

the big question is what to do. certainly the 3 you have used don't seem up to it.

certainly the straight forward answer (previously said) is get a surveyor who specialises in damp. ask for a written spec of what he is going to do before engaging him and what his charge will be.

trouble with this is spending money when a "good" damp proofer is obliged to do this by law and will normally do it for free (it's included in the price for the job).

i would get 3 quotes from national damp proofing companies or local companies that are tried to national companies. then post questions on anything you need help on to work out whose best to go with.

if you can describe what the visible problems are and their extent along with what prompted the initial surveys i can post my gut feeling or whether some simple tests could help.

 

[Bilioustrumpstaine]

As mentioned before the OP needs a qualified surveyor who has nothing to gain (except his fee !) from the outcome of the survey.

I went to a property where a salesman had almost convinced the occupier that they had rising damp, they were on the first floor
Installation of a dehumidifer and use of the previously closed trickle vents and the problem went away

 

[PerryOne]

I would suggest that you take a look yourself.
Rising damp, does what it says.
It rises through the mortar between the bricks.
As such its easy to identify.
Rising damp if left alone, will rise to about 3 feet above the ground outside.
When you knock off the plaster, where you have identified that there is a rising damp problem and check it out with a damp meter - thats one problem solved.
If someone has tried to cover it up, then the damp will rise higher.
Condensation.
Simple. You cause condensation by breathing, sweating, washing, just living.
Each member of your family breathes out 46 grams of water vapour per hour.
Its estimated that each person adds 2.5 litres of water vapour to the air in their home every 24 hours.
You recognize condensation, by the fact that it forms wherever you have a cold surface.
Normally windows and cold walls. Do your windows steam up? If yes.
Then you have condensation.
If yes, buy a de-humidifier to sort the problem. Buy one that takes 10 litres of water from the air every 24 hours. Turn it on, leave it on 24 hours a day. Do not turn it off at night. As low temperature = condensation.

 

[PerryOne]

Hello again, sorry I was called away to dinner.
OK. May I've told you how to identify rising damp, because it sit low round the walls.
Now you need to look outside in the garden to see if you can spot the culprit.
Rising damp in 1950's houses is very often due to people laying paths or patios and bridging
the damp course or raising flower beds, or putting water butts against the wall or porches.
Take a horizontal line from the bottom of the front door and go round the house to see if
any of these things is happening, if it is sort it! The ground outside needs to be at least 6 inches below the damp proof course. Job done.
However, if there is nothing naughty outside, then look at the outside walls, look for cracks, leaking pipes, leaking gutters, leaking roof = water can run into a wall from any of these things.
Its captured above the damp proof course and lays in the wall until the summer time, when hopefully it goes away.
Condensation, again.
Condensation will form at any hight! Floors, walls, windows, ceilings anything that is cold. (Thats how its different from rising damp.)
It forms when the temperature in the room drops, usually because someone turns down the heating or turns it off.
When night comes the temperature outside drops, the windows get colder.
Very often someone closes the curtains or blinds, this causes the temperature in the window space to plummetes = condensation.
Condensation forms, behind curtains and furniture wherever the air is trapped and a cold space forms.
The ways to stop it, open the windows, let the moisture out and freeze.
Keep the temperature in your home steady. Warm air = warm walls etc less visible condensation.
However, you and your family are still putting the water vapour in - eventually the air will be overloaded and water vapour, a very tiny gas, will start to settle inside your bedding, clothes, everything in your home.
Your bed and clothes will feel cold.
Once the de-humidifier is extracting all this water vapour, you home will feel much dryer and warmer.
Final point. The de-humidifier will pay for itself as dry air costs less to heat than damp air.

 

[Joe Malone]

The previous contributor has got it completely wrong on all counts. I'll say it til i'm blue in the face... you cannot check for rising damp using a handheld electronic moisture meter.

The advice on condensation is also wrong and I've been battling bad advice like 'turn up the heating and open the windows' for years. Opening the windows reduces the internal air temperature meaning that the air has to give up moisture in the form of condensation. I suggest you read the Chartered Institute of Environmental Health's paper on managing condensation.

Condensation moisture profiles can mimic rising damp profiles exactly (though more often you'll get generalised readings throughout the room.) This is due to the fact that heavy condensation tends to run down the wall and pool near the wall base but there can be other factors linked to cold bridging problems at the wall base.

You'd first check for visual evidence related to condensation damp problems. Is there a generalised outbreak of black spot mould or is it confined to corners in the classic crescent shaped pattern. Do you have high relative humidity levels with surface temperatures below dew point temperature? Are there occupancy, heating, ventilation or thermal insulation issues that might contribute to a condensation damp problem?

The important point to remember is that condensation will produce surface moisture and will not produce moisture at depth within the masonry. A simple test to confirm surface moisture would be to use deep wall probes connected to a Protimeter. The absence of moisture at depth would tend to confirm a condensation damp problem. Remember using deep wall probes will not give a quantitative reading, only a Calcium Carbide test will give accurate site moisture profiles at depth. Scan meters are not a reliable means for testing for moisture at depth, they work to a nominal depth of 12mm so quite often won't even measure beyond the plasterwork. Scan meters are commonly used within the DPC industry now because they supposedly measure moisture at depth, conveniently this often tends to support a rising damp diagnosis. Let me assure you that the use of scan meters has not improved dpc 'specialists' hit rate for correct diagnosis.

You can test for salts, the absence of Nitrates and Chlorides would support a condensation damp diagnosis rather than confirm it.

Also don't be surprised if you find more than one cause of damp, it's not unusual to find more than one cause of damp in a property, you just have to take a very methodical approach to the investigation.

 

[^woody^]

I'll say it til i'm blue in the face... you cannot check for rising damp using a handheld electronic moisture meter.

You can use the meter to get a good idea that the moisture is coming up rather than going down, and after using the meter to do a whole wall survey at defined points (grid) then it can be pretty conclusive as to the most likely cause. Sharp rises in readings at certiain points as opposed to gradual changes have specific meanings as to the likley cause

Obviously, this is done a host of other checks and eliminations to narrow the cause down to the most likely.

The meter is a tool, and used correctly can be a useful tool.

One can check for rising damp with a meter - however its not the meter that will determine if the moisture is rising, but the operator

With regards to your comments on condensation only on the surface and dry walls beneath, arn't you forgetting intersitual condensation, and especially a combination of the two which can give unusual diagnosis problems?

 

[Joe Malone]

Woody, you make some good points regarding the use of these metres. Taking the 'grid' approach is essential but irregardless of this they will only ever be an indicator that further investigation is required. There are several reasons for this:

1. They are not calibrated for use in masonry. The readings are qualitative not quantitative. For example a fully saturated engineering brick will only hold around 3-4% moisture but will register 90-100% on a damp meter.

2. They measure electrical conductance not damp. A salt band will give high moisture results and skew the profile. In reality it is the electrical conductivity of the salt that has given the high damp reading and the result is meaningless.

3. Any material containing a high carbon content will gve a high damp reading. Clinker blocks used extensively after the war are a prime example.

4. 'Foil Damp' a foil backed lining paper will give uniformly high readings but the wall may well be dry. This has been used extensively by Local Authorities.

5. Damp profiles are not evidence of rising damp they are simply a starting point for further investigation. A plumbing leak at a wall base would eventually mimic a rising damp profile exactly as can condensation damp.

6. Using a handheld meter in isolation for diagnosing rising damp is contrary to BS6576, the damp industry code of practice.

The damp industry will continue to misdiagnose at the publics expense until it accepts the limitations of handheld electric meters and starts charging for a proper survey.

I haven't forgotten interstitial condensation, it just wasn't mentioned and is a subject in itself.

 

[PerryOne]

Joe, did you really read the words I wrote?
Or did you just react to what you thought I wrote?

Para one.I did not say check for rising damp using a hand held.
Read what I wrote.

Para two. I did not say open the windows to solve the problem or turn up the heating.
Read what I wrote.

I provided a simple, don't believe anything you may have been told, request to May, in essence. Look, and find out for yourself. There is no magic, it is really very simple! Anyone can do it!

I can go on about damp and condensation all day and manage to bore most people into a numbed state.

What you do not seem to understand, is that we are writing about a 1950 house, that was built at a time of poor design and poor quality

We are not dealing with 400 year old farm house with five foot thick walls comprised of stone and lime mortar, that will in all probability never dry out!

 

[Joe Malone]

Perryone, apologies if i've misunderstood something you said but these are the individual points that I don't agree with... Damp sitting low around the walls does not identify rising damp. If the damp is caused by bridging then technically it's penetrating damp. Condensation can form at any height but because heat rises and low level surfaces are cooler then quite often condensation profiles mimic rising damp profiles. Lack of moisture at depth is the key to diagnosing condensation damp. You clearly say open the windows and this is bad advice. I also don't agree with running a dehumidifier; sure it'll work whilst it's running but it doesn't deal with the problem at source. I can't imagine anyone wanting to run a dehumidifier indefinitely.

OK. May I've told you how to identify rising damp, because it sit low round the walls.

Rising damp in 1950's houses is very often due to people laying paths or patios and bridging


Condensation will form at any hight! Floors, walls, windows, ceilings anything that is cold. (Thats how its different from rising damp.)

The ways to stop it, open the windows, let the moisture out and freeze.

Once the de-humidifier is extracting all this water vapour, you home will feel much dryer and warmer.
quote]

 

[Shytalkz]

The damp industry will continue to misdiagnose at the publics expense until it accepts the limitations of handheld electric meters and starts charging for a proper survey.

A fair amout of valuation surveyors would do well to accept this too...

 

[PerryOne]

Joe, It was only after the Great Fog, just after the War and the Clean air Act that condensation raised its ugly head.
Until then, in this county at least, almost everyone had an open fire with plenty of ventilation and little or no condensation.
Sadly the Clean air Act lead to "EssoBlu" with every night adverts on TV for "EssoBlu" paraffin and the paraffin fires in most homes.
And as you know burning paraffin in a closed room guarantees condensation.

The next chapter was the oil crisis of the 1970's when people became concerned at the high price of fuel and draft proofing became a vogue. To the second oil crisis where saving fuel and cost became a National hobby.

That is the history. Open windows and drafty fires guarantee no condensation.

I think that May's words make it clear that, up to now, she has preferred to be warm with closed windows = little ventilation, rather than blessed with open windows, fresh air and freeze. Probably not relating her actions to the cause of condensation.

May, faced with three confusing options, all costing a lot of money turned to the Webb for further opinion. This I gave her, in its most simple form. I wrote, do certain simple things, and obtain clarity by elimination.

I fully understand that there are more possibilities, however, to present a confusing and complicated series of possibilities would not help.

May can simply walk round her rooms, identify where the patches of damp are, if they are high, they are probably condensation.
To clarify this, keep the temperature steady (I wrote. I didn't write turn up the heating!) turn on the de-humidifier see if they go away.(A little cost option.)

In respect to the possible rising damp. I wrote walk round the house and check that the damp proof course has been/not been bridged.
This will have taken her a few minutes. At which point she will know if the damp proof course is/was bridged and can take the appropriate (Cost free) action. More importantly this part of rising damp will be eliminated.

Once these simple things are done she is in a better position and can come back to the forum and say yes that was the problem, or no that didn't solve it for me - what do I try next.

And like the experienced chap you are, you will tell her what you would look for next.
Were you one of those salesmen?
Perry