Relative Humidity Data Logging for Damp Basement
Damp can be a major issue in the home. Find answers to questions or post your own here.

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Relative Humidity Data Logging for Damp Basement

by burt12345 » Thu Feb 12, 2015 4:39 pm


I bought a USB Temperature Relative Humidity data logger devices a few weeks ago.

I'm using it to measure RH in our basement (terraced party walls both sides, retaining wall to rear, front opens to street level) - we have removed some plasterboard boxing in and plastic sheet "damp solution" on the retaining wall and the old plaster/paint off our sandstone basement walls in a bid to find out exactly what is going on down there starting from bare walls, as we want to make it less humid naturally - probably through ventilation ultimately, and letting the walls breathe rather than seal in the damp.

However, I've realised I've been collecting data from the logger - all very interesting, but haven't got the foggiest how to interoperate it, and therefore don't know what I'm trying to achieve or what the readings are telling me.

Are there any guides anyone can point me to? It would be really useful to have a real world case study of what a damp basement's reading looked like at the beginning (with a how not to solve basement damp), and see data snap shots of the effects of solutions as they are implemented.

I'm thinking my my end solution will be to create stud walls with rockwool/breathable insulation, plasterboard and good ventilation. I appreciate every house is different.

Any pointers would be much appreciated.



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Re: Relative Humidity Data Logging for Damp Basement

by Perry525 » Sun Mar 08, 2015 3:24 pm

To understand the humidity in your basement, you need to know the humidity outside as well.
When you measure humidity, the result is relative humidity, that is based on a mixture of the temperature at the time and the amount of water vapour in the air.
For a given amount of water vapour in the air, the same amount of water vapour, will produce a different reading for every degree difference in temperature.
For example:
At say 30 degrees centigrade and 100% humidity there is about 12.5 grams of water in a cubic metre.
At say 0 degrees centigrade and 100% humidity there is almost no water vapour in a cubic metre of air. (all the water vapour has turned to ice/frost and has dropped out)

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