Proper moisture test on concrete

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  #1  
Old 06-22-09, 07:40 PM
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Proper moisture test on concrete

What is the proper way to do a moisture test on a young (1 year old) concrete floor? My husband and I are building our own house in Tampa Florida and I want to lay the floor. The house is slab on grade and I want to put down about 1000sqft of engineered hardwood. What is considered to be an acceptable amount of moisture? If there is too much moisture is this type of flooring a bad idea? I am a complete newbie as far as wood floors are concerned and I have many more questions. But I thought I would start here with this question.
Any help is appreciated.
Dorothy
 
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Old 06-23-09, 04:49 AM
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There are meters that will tell you how much moisture you have.
 
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Old 06-23-09, 10:15 AM
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Meters aren't very accurate, but they are good at identifying a potential problem...basically, you can use them for a "green/red, go/no-go" type of conclusion. For accuracy, the best test for a homeowner is a Calcium Chloride (CaCl) test. Here's some info from Taylor Tools, and their kits are usually easy to find in every part of the country.
Calcium Chloride Moisture Test Kit

The slab needs to be free from contaminants and sealers. Grind the areas where the tests will be placed. 3 test areas for the first 1000 s/f. Follow the directions closely. As a general rule, 3lbs of moisture emissions per 1000sf per 24hrs is the limit for direct glue down (don't worry,once completed, you can send the kit back to Taylor and they will do the calculations for you). 3lbs-7lbs and you should use a vapor retarder. Above 7lbs is normally considered unacceptable for wood floors.
 
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Old 06-23-09, 07:48 PM
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Originally Posted by tn.floorguy View Post
Meters aren't very accurate, but they are good at identifying a potential problem...basically, you can use them for a "green/red, go/no-go" type of conclusion. For accuracy, the best test for a homeowner is a Calcium Chloride (CaCl) test. Here's some info from Taylor Tools, and their kits are usually easy to find in every part of the country.
Calcium Chloride Moisture Test Kit

The slab needs to be free from contaminants and sealers. Grind the areas where the tests will be placed. 3 test areas for the first 1000 s/f. Follow the directions closely. As a general rule, 3lbs of moisture emissions per 1000sf per 24hrs is the limit for direct glue down (don't worry,once completed, you can send the kit back to Taylor and they will do the calculations for you). 3lbs-7lbs and you should use a vapor retarder. Above 7lbs is normally considered unacceptable for wood floors.
Thanks for the info on the test kit. now I just have to find a retailer. I checked the taylor site and it looks like all the places around here that carry the kit only sell to the trade. I will make some calls. Any idea how long it takes them to get the results back to you? I assume that i should palce the test kits in 3 widley spaced areas of the conrete where I am going to lay floor. Like in the foyer, hallway and living room. I want to use a click and loc floor since this is the first ime I have done this. Being a newbie can I do a glue down? Is glue down feasable in Florida? My house will not always be closed with the AC running in the summer. Right now the humidity is about 90% and it is not raining.
Dorothy.
 
  #5  
Old 06-25-09, 07:21 AM
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You would want to spread the tests out. They usually get the results to you in just a few days. You can also weigh the dish yourself and use their online calculator. Sending it to them is just a good idea because they document it and keep it on record if you ever have a dispute.

Glue down may be okay, depending on where you are exactly, but then there wouldn't be any reason to worry about a click/lock type floor. If you want to do a click type system, I would float it, as they are primarily designed to do so. This works two-fold: It's less labor intensive for a do-it-yourselfer, and substrate moisture is less of an issue. You would still want to do at least some basic testing to make sure there is no unusually high moisture levels, but if you float it you can seal the concrete, cover it with a vapor barrier and pad, then float your floor on top.

As far as the ambient conditions in the home, I would caution you to try to maintain them as tightly as possible. Most manufacturer's require 35-55% relative humidity and a temp of 60-80 degrees. If it's not feasible for you to maintain those conditions, avoid hardwood....explains all the tile in Florida, huh?
 
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