Dampness in basement

[nDracut]

I have a new construction house. During the heavy rain in May - June in new-england (NE), my basement got water around 4-8 inches. My house has perimeter drain around the foundation. So it was not supposed to get the water in the basement. But after I got the water, I pumped out the water and builder came and installed a pipe under the bed (of basement) from outside. So any water collected under basement should be flowing out.

But still my basement is damp. I am running the dehumidifier continousily (24 hrs a day). AFter 2 coats of DRYLOK (masonary based paint) still some parts of damp. Builder is reasoning "it may be due to the water condensation in the concrete floor".

What could be the reason? how ot fix this problem so the basement will be dry?
Should I run dehumidifier 365 days a year?

Thanks,

[chumpchange]

First, Drylock is not vapor resistant, it is only resistant to hydrostatic or water pressure. It is purposely permeable to water vapor. So if there is dampness behind your walls (poor foundation waterproofing), it will drive the water vapor through the Drylock. Also, your basement surfaces are cold and now, painted. If you leave the basement windows/doors open to the outside air (or even the upstairs air if the upstairs isn't air conditioned) in the summer, it may condense on the cold floor and walls.

The right thing to do when using UGL products in the basement, assuming you don't have water pouring in, is to SEAL the concrete first with their oil based concrete sealer. This product is vapor resistant, and can be painted over with either the Drylock latex or oil based paint if you still have liquid water leakage issues. This cannot be done now, as the paint was applied first.

It is not unusual to have to run the dehumidifier all summer. Hopefully it will become less necessary as fall and winter approach. Get a good humidity meter for your basement, and target a 50-60% humidity. If the humidifier never stops and proper humidity is reached, it could be a broken humidistat...all too frequent with store-bought dehumidifiers. Also, most dehumidifiers are not rated to operate below 65F, so if you still need it in the winter and your basement is not heated, you need to go look for a cold weather rated dehumidifier (Whirlpool makes one, as do some others-don't get Sears Kenmore...they make good air conditioners but poor dehumidifiers).

Ensure the ground slopes away from your foundation all around, and that downspouts are not clogged, and are draining 8 feet away from the foundation.

If your slab isn't painted, go get the UGL concrete sealer and apply it per instructions. You will need to massivly ventilate your basement...pick a time when kids won't be around for a couple of days.

[richard]

nDracut,

If the exterior drainage system failed so quickly I would suggest addressing the basement water problem with a water control system that a Basement Systems dealer can explain to you.

Go to our Learning Center to find out about negative-side waterproofing products such as DryLock and other sealers.
http://www.basementsystems.com/learning_center/basement/index.php

As for the dampness, as chumpchange stated, it is very common to have to run a dehumidifier all summer, especially in New England. Basement Systems Energy Star-rated SaniDry basement air system can efficiently lower your relative humidity (RH) to a comfortable level (note that mildew and most molds grow at RH levels above 50%, so keeping your RH below 50% will eliminate musty smells as well as prevent mold growth).
http://www.basementsystems.com/dehumidifier/

For a Free inspection and estimate contact your local Basment Systems dealer by calling 800-638-7048, or fill out the form at: http://www.basementsystems.com/forms/contact.php

Thanks for your question.