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Moisture Prevention
updated: Sep 13, 2012, 11:54 AM

By Edhat Subscriber

My wife and I recently purchased our first home on the mesa, which we absolutely love. However we are worried about the presence of moisture in our crawl space... as it appears to be coming up into the house in certain areas. Does anyone have experience with this? I'd like to hire a local contractor to assess the condition and offers some possible solutions, but I'm not sure where to start. I've been under the house and can not see any clear leaks but it the air is defiantly thick down there. any suggestions are appreciated.

Comments in order of when they were received | (reverse order)

COMMENT 319363	2012-09-13 12:02 PM
An engineer that we had come to our house for a consultation once told us "you can only divert water, you can't prevent it from choosing its path of least resistance." We installed French drains. We installed gutters/downspouts that connected to underground drainage pipes that took water from our roof to the street instead of the ground next to our house. I'd recommend a consultation with an engineer.
COMMENT 319379P	2012-09-13 12:58 PM
I have just lived with it for over 38 years because I live close to the ocean and was told it would never not be damp down there. My neighbor took 363's path, but still has dampness under the house. When it gets really damp, like in years when we have a lot of rain, I run a dehumidifier in the house next to the furnace cold air intake because the furnace is vented to the crawl space. Not perfect, but a lot cheaper than the french drain gutter solution which does not seem to work any better. Oh yes, other thing is make sure that you have enough vents around the base of the house into the crawl space. Once when we had standing water under the house because of a really bad rain year and flooding we had to pump the water out and then we rented a large fan - the kind they use for drying carpet after a flood - and ran it at the entry way to the crawl space for about a week. That solved that problem.
COMMENT 319384	2012-09-13 01:11 PM
We found the same issue when we bought here in San Roque a year ago. I've discovered that many houses have the french drains filled with gravel down to 7' deep, a sump pump to pump the water out and heavy plastic sheets on the ground in their house crawlspace. We put in a pool this summer and when they dug the hole, water was flowing laterally out of fissures in the clay layer! Very interesting to see... Fans help to dry out the crawlspace so you don't get that musty smell but it's not a fix. I'd like to just put plastic down but you'll still have moisture under it and possibly mold issues. We'll be putting in our drains soon.
COMMENT 319390	2012-09-13 01:27 PM
You could go back to LA where the houses are drier.
COMMENT 319391	2012-09-13 01:28 PM
Ask 10 contractors for opinions on moisture in crawl space, and you will get 11 opinions. You will hear do nothing all the way to suggestions to do tens of thousands of dollars work. You will hear put in $100 of moisture barrier plastic, to sue your seller and agent. Let us know which way you go! You might want to wait until we have rain to see what's really going on. Standing water is your main enemy.
COMMENT 319393	2012-09-13 01:42 PM
Has anyone tried foundation fans? A floor guy suggested that to us. I don't understand how this helps if the air outside is humid or foggy.
COMMENT 319398	2012-09-13 01:59 PM
I recently spotted some moisture under the house. Guess what? Turns out there was a leaking pipe in the yard (hidden by vegetation) which was at a slightly raised elevation from the house. No water visible in the yard, it was tunneling into the ground, then under the house. Luckily, the City water department will give residents a partial waiver on any large water bill resulting from a leak (can apply once every 5 years). After a really big rain, we sometimes get water under the house and have to place a few large fans near the vents.
COMMENT 319402	2012-09-13 02:04 PM
393 .. I suppose that would depend on what neighborhood you live in. On the Riviera, its often much warmer and drier than locales near the beach.
COMMENT 319416	2012-09-13 02:21 PM
The underside of the house is never quite fully dry especially if you live in an area that is really damp at least half the time (think night time and when the fog or marine layer provides cover for a good portion of the day). Even aside from leaky pipes or poor drainage slopes dampness collects under the house as there is nothing to cause it to evaporate away. It is cool and only through good air circulation can it be vented away. But it will never reach the level of dryness you might expect up above in the bright light of day. Scoop out some dirt you think is particularly damp or wet and bring it out to the light of day to examine. Is it really wet or just feels that way when you're down in a dark, damp hole in the ground?
COMMENT 319483	2012-09-13 03:23 PM
My neighbor dug a sump under their house and when the sump fills up a pump turns on and discharges it to their driveway. If you've checked for leaks and other obvious sources of water, french drains and a sump pump are pretty standard solutions. But if you have clayey soil putting in a trench filled with gravel or sand won't work as the high suction pressures in the clay soil pores will suck the water out of the french drain gravel or sand. So make sure the person analyzing the site understands soil/water interaction before you spend any money on the fix.
COMMENT 319493	2012-09-13 03:32 PM
You have all the suggestions you need, we did the sump pump and french drains. Just one little side note, if you have moisture under your house you may have mold under your floorboards and even growing up the inside of your walls. Be sure to check for that too as it is a very serious health hazard.
COMMENT 319494	2012-09-13 03:38 PM
Moisture and dampness can be normal. Free water is a big issue. Drainage is key - water should never be allowed to pond near or against your house. All water should be positively collected and direct to the street (never neighboring properties). Rain gutters should be installed and outleted away from the foundation, area drains, if they exist must, be checked and maintained. Areas adjacent to the house should be graded to slope away. A geotechnical specialist is called for hear. You could look up Mike Hoover.
COMMENT 319724	2012-09-14 08:08 AM
On the Mesa, there is a high probability of mildew/mold, the closer you are to the ocean. If you see any, it might be a good idea to have the house checked and find out how to limit the damage. Very bad over time for your health.
COMMENT 319832	2012-09-14 10:15 AM
I lived on the mesa for 30 years. If you live on the mesa get USED TO IT. That is all. Unless, like everyone else who seems to be moving in up there, you are uber rich (ughhh!) and you can barricade your house against the sea air.
COMMENT 319884	2012-09-14 11:26 AM
just wait till it rains again
COMMENT 320111	2012-09-14 04:55 PM
I would sue the seller and the real estate agency if the moisture problem was not disclosed in the required disclosure statements on your real estate purchase contract. I would, I would, I would!!

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