Damp Floor Slab? - General DIY Discussions - DIY Chatroom Home Improvement Forum

Go Back   DIY Chatroom Home Improvement Forum > DIY Forum > General DIY Discussions


Thread Tools Display Modes
Old 03-04-2011, 10:00 PM   #1
PatrickGSR94's Avatar
Join Date: Mar 2011
Posts: 72
Rewards Points: 87

Damp floor slab?

My house is 9 years old and is built with concrete slab-on-grade construction. I pulled up the vinyl flooring in the kitchen last weekend to prepare for new porcelain tile. My office has a Flir thermal imaging IR camera and Extech moisture meter like this one: http://www.extech.com/instruments/pr...=11&prodid=518 so I decided to try it out in my house.

So I set the meter on the bare concrete floor in lots of different locations all over the kitchen and pantry, and EVERY location showed 99.9% moisture. The slab doesn't really feel damp to the touch, and I'm pretty sure the meter is working correctly. I placed the meter on the drywall of the exterior walls near the floor and it only read about 6% moisture in that area.

Could my vapor barrier really have broken down in just 9 years? Or maybe the builders were so dang cheap they didn't even use one? I have glue-down engineered wood floor in about half the house, some carpet, and some tile in a bathroom and haven't really had any problems with any of the other floors in the past.

Is this something I should worry about?


PatrickGSR94 is offline   Reply With Quote
Old 03-05-2011, 06:17 AM   #2
Join Date: Dec 2008
Location: Wilmington, DE
Posts: 3,118
Rewards Points: 2,000

There is a test that is better than hi-$$$$ cameras, but just as effective. Tape a piece of aluminum foil or plastivc about 12-16" square to the cement, tape all edges tightly. Check after 2-3 days. If moisture is there, you have a problem. If you have a problem, make sure rain gutters/downspouts are working and they get water at least 6' away from the foundation. And grading that does the same thing.

You would still be able to install tile, using thinset mortar. Other types of flooring would require moisture barriers. But the problem should be addressed if it exists.


Just Bill is offline   Reply With Quote
Old 03-05-2011, 06:22 AM   #3
Jackofall1's Avatar
Join Date: Dec 2010
Location: Southern Michigan
Posts: 2,822
Rewards Points: 2,000

Good one Bill, on the moisture present simple test, fail safe and needs no calibration!

When its all said and done there is usually more said than done
Jackofall1 is offline   Reply With Quote
Old 03-11-2011, 12:24 AM   #4
Join Date: Dec 2008
Location: Fairbanks, AK
Posts: 1,893
Rewards Points: 1,092

if poly deteriorated under a slab in 9 yrs, 90% of the homes in the US would have wet floors. the contractor did not use a vb, i suspect. ask a qualified concrete cat if it is possible, and advisable, to seal the concrete. the thought of having a concrete floor wet all the time is spooky, so it may not be advisable. it may be better to let the moisture through and deal w/ it inside.
jklingel is offline   Reply With Quote

Thread Tools
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
Damp Insulation in Attic wiz561 Building & Construction 6 12-23-2010 11:16 PM
Bubbling paint on ceiling caused by damp bathroom floor garv19 General DIY Discussions 4 04-10-2010 07:38 AM
Damp Carpet KRyanM General DIY Discussions 5 01-09-2010 09:32 AM
Damp walls lara1234 Building & Construction 6 10-28-2009 03:10 AM
Damp walls - should I use foil bubble wrap!? thenap80 Building & Construction 7 12-18-2008 11:40 PM

Top of Page | View New Posts


Search Engine Friendly URLs by vBSEO 3.6.1