Discuss Using our MFT on 500v IR as a damp test probe? in the Electrical Forum area at ElectriciansForums.net

Marti

Electrician's Arms
Messages
232
Location
Romford Essex
OK, Stop laughing at the back!
SO, I'm house hunting and, ignoring the number of beautifully decorated houses with shite electrics - I also want to be aware of any damp issues. This led me to try using the trusty Megger with sharp probes to test for damp. This appears to work, or at-least is better than a cheap damp test gadget 'cos the pro stuff is pricey and is unlikely to be used again.

Any of you sparkin' heroes tried this? Am I barking up the wrong step ladder?
 

Robson689

Regular EF Member
Messages
191
Location
UK
Damp cannot be diagnosed with a meter it's a con to sell you chemical injection

Samples of the masonry need to be taken for analysis
 

Cid

Regular EF Member
Messages
97
Location
London
Yeah I done it when there was a burst water mains outside my house. It works but there is no way of interpreting the numbers.
 
OP
Marti

Marti

Electrician's Arms
Messages
232
Location
Romford Essex
Surely the survey will have that covered?
Unfortunately bitter experience has shown that, just as there are drive-by EICR's, similar scams happen in house surveys. RICS are just a fully paid-up protection racket for the unscrupulous. Just as well that'd never happen in the field of electrics ;)
 

PEG

Respected Member
Mentor
Electrician's Arms
Trainee Access
Messages
5,002
Location
Manchester
There are many types of "damp",and you may be better off,investing in some research,of it's effects,and methods of rectification.

You can get a meter off ebay,for checking moisture content of logs,for less than 20 squid. This would give you a rough indication of surface damp,but no great accuracy,or proof of a problem.

An empty,un-heated property,will start to increase it's moisture content,in line with factors such as humidity,ventilation,and any "extras".
A window full of condensation,could give adjacent walls a high reading - but be fine,whereas,an area totalled ravaged by wet-rot,could now be dry,and not give an indication.

Two biggest factors,are firstly,construction methods and materials.
This is the cause of 95% of all damp issues.

The second,is location.

I am not straying from damp to wet,and drainage,subsidence and ground heave...

So,do some reading,and rather than look for a specific part,which shows damp,look at the areas where it could begin. Any bridging,alteration,deviation,etc,of the DPC - whatever initial construction method,and consider if what appears to be there,is working.
Most accepted damp issues,internally,are ventilation problems.
Cavity wall injection blags,have not always helped this...no point having the place insulated,if still moisture,because the warmer air can contain more water...then you have to ventilate...windows open...heating up the garden,now...marvellous;)

Do not underestimate the importance of air-bricks. Sub-floor ventilation,has been belittled,by countless builders,cavity insulators,landscapers,pavers,etc,and been the ruin of many a property.:)
 
OP
Marti

Marti

Electrician's Arms
Messages
232
Location
Romford Essex
That is really useful - thank you. Thinking about our trade; I'm reluctant to become the dodgy DIYer in another skilled area whilst recognising that, if I can communicate with a good surveyor I may avoid the pain and expense of unforeseen issues.
 

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