Crawl Space very dry now but...

I did the plastic thing as advised on the ground and up the block wall but I can't seem to keep the duct tape from peeling off and the plastic falling back to the ground. Right now I have used silicon ( clear) on the duct tape , sticky side, and the tape seems to be holding but for how long. Is there a tape that will stick to block and painted block and hold the plastic up?..... Is there a caulk, I tried liquid nails maybe I tried the wrong one it did not even stick at all.

FYI the crawl space is at 35% humidity even when the outside is near 100% humidity and I'm very well satified. The dehumidifer now cuts off and then on according to the humidity level down there. I was surprised that the dehumidifer could do what it did, matter of fact I did not think it was possible..as wet as my crawl space has been for years in the summer. George K

 

just a thought, but applying mastic over the tape should do it

 

What is "mastic" I don't think I have heard of such.????

 

I had a similar problem in my crawl space - very high humidity and condensation on A/C boots, ductwork, and metal distribution boxes. It's a long story. Short version is that I have had to tear out old ductwork and replace with new, put black plastic on ground, had to replace a hardwood floor, lots of mold and mildew on joists and subflooring, delaminated subflooring, have installed Leafguard gutters, have landscaped to force rain water away from house, have had several professionals out to try to figure out my crawl space moisture problems - to no avail. Have cleaned A/C coils, checked drain pan and drain line. I did all that, cranked central A/C up (gas pack) and still have condensation problems. I went back to window units until I could figure out the problem.

Originally crawl space humidity was around 90%. I sealed up vents and it went down to 82%. I still had condensation problems when I used central A/C. Bought and installed Whirlpool 70 pint dehumdifier 7 days ago. Have plugged up all holes in foundation and put black plastic on foundation walls within the past week. Humdity is now down to about 50% but I haven't done the acid test yet - cranking up the central A/C. I'll try that in a few days.

To cover my foundation walls, I cut the plastic into 8 1/2' by 5' strips and glued them to 8' treated furring strips and nailed them to the foundation wall. I used 2" concrete nails and nailed into mortor joints. I had about 3" of plastic overlapping each furring strip so I could go back and glue the sections together if I had to. I left about 3" at the top of the foundation wall not covered as a termite inspection strip. I used "Nail Power" Pro Grade Molding and paneling adhesive to glue the plastic to the furring strips. I applied the glue to the furring strip and then laid the strip on the plastic and pressed it down real good and put some weights on it for a while. It seemed to work pretty well.

I would really like to get my crawl space humidity down to 40-45%. You have done great to get yours down to 35%. What brand and capacity dehumidifier are you using? What settings do you have it on? How long did it take to get your humidity down to 35%?


Thanks

PS. I live in Wake Co. NC.

 

70 pint Kenmore does the job, I actually got it to dry in the crawl space and have since re adjusted the dehumidifer to 45%. My crawl space is large and it is very tight I used dry lock and palstic like you did. I am very satified so far. Matter of fact I was pulling 5 gallons of water every 8 to 10 hours for a week then I started seeing some results.

 

I just finished taping the sections of plastic on the foundation walls together today so I'll see what that does for the humdity. So far the lowest I have seen it is 48%.

I can hear the compressor cutting off sometimes but the fan still runs. I have it on "Continuous Run" which means "keep dehumidifying regardless of what the humidity is". I'm getting nowhere near 70 pints per day condensation (probably half that - maybe 2/3 best case). Seems to me the compressor should run all the time unless it freezes up. Does the fan on your dehumidifier cut off when your compressor cuts off?

 

yes, unless it is defrosting.

The condensed may have reached the proper temp on the coil and is just cycling.

 

I am working on correcting the same problem that both of you have had but I have read that it may be better to vent the crawlspace with a fan hooked to a humidistat depending on climate. The house is in Western Maryland.

 

Thats good if you do not have 80% humidity 9 months out of the year, I have to remove the humidity and keep it out that why you seal up the crawlspace and close of the vents and turn on a dehumidifier.