Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Building & Construction

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 02-26-2007, 05:30 AM   #1
Newbie
 
Join Date: Feb 2007
Posts: 2
Share |
Default

moisture testing with a multimeter


I think it should be possible to compare the dampness of different walls by using the resistance option on my multimeter. When the leads are not touching anything the digital screen reads 1. As I test various walls I get readings between 200 and 1800. Intuitively it seems that 200 is wetter than 1800 - am I right?

ronhud is offline   Reply With Quote
Old 02-26-2007, 06:53 AM   #2
Member
 
concretemasonry's Avatar
 
Join Date: Oct 2006
Location: Minneapolis/St. Paul, Minnesota - Latitude 45.057 Longitude -93.074
Posts: 3,707
Default

moisture testing with a multimeter


You may get the relative differences (wetter, dryer) of 2 walls made of the same materials IF they have been stabilized(moisture-wise) for a few days or weeks.

You can fool yourself very easily since you mat be dealing with only one layer (like the paper on gypsum board) and not the entire material.

What you are getting as far as results is a little better than a guess if it is for something important.

There are good dedicated meters for specific purposes and materials. My set up is about $600.

concretemasonry is online now   Reply With Quote
Old 02-26-2007, 07:18 AM   #3
Newbie
 
Join Date: Feb 2007
Posts: 2
Default

moisture testing with a multimeter


ConcreteMasonry - thanks for the reply. I should have been more specific. The situation is that I have a series of small cellars and one corner of one of them seems to precipitate a lot of condensation. I thought of testing the comparitive dampness of the walls ( bare brick) to get some idea of where the moisture is coming from. 80% of the cellar area is dry so it appears that there is some local source of the moisture. I appreciate that this terribly unscientific.

Ron
ronhud is offline   Reply With Quote
Old 02-26-2007, 07:31 AM   #4
Member
 
concretemasonry's Avatar
 
Join Date: Oct 2006
Location: Minneapolis/St. Paul, Minnesota - Latitude 45.057 Longitude -93.074
Posts: 3,707
Default

moisture testing with a multimeter


Condensation is dependant on the moisture content and the temperature of the material that the water may condense on.

I think you are looking for something other than condensation.
concretemasonry is online now   Reply With Quote
Old 02-26-2007, 07:48 PM   #5
Member
 
Join Date: Jan 2007
Posts: 221
Default

moisture testing with a multimeter


To answer your original question, since water is more conductive than no water,

low ohm number = lower resistance = more water

though what you are actually measuring is debatable, as said above.
elementx440 is offline   Reply With Quote
Old 02-27-2007, 06:39 AM   #6
General Contractor
 
joasis's Avatar
 
Join Date: May 2006
Posts: 876
Default

moisture testing with a multimeter


The impurity of water will affect the resistance value. Pure water will have infinite resistance, since it will not conduct electricity. Salt water readly conducts, as will hard water. So without knowing the value of the medium (water, moisture), you would have no comparitive value to base a test.

I use a moisture meter to check rough sawn lumber for MC....but that is a dedicated use, and it requires a standard of testing for accuracy.

__________________
Ladwig Construction
Hennessey, Oklahoma
405 853 1563



joasis is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Testing for a gas leak haynesk Plumbing 2 07-27-2007 07:11 PM
To Moisture Barrier or Not to Moisture Barrier? cordon Flooring 7 05-22-2007 09:48 PM
moisture barrier - help! jediracer Carpentry 12 10-03-2006 06:32 PM
Plan for solving basement moisture problem krx Remodeling 1 12-04-2005 07:00 PM
Concrete slab weeps moisture dale h Flooring 2 04-30-2005 10:29 AM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.