I have a 1.5 story house that sits on a hill. The part that has the basement has been excavated around by about 2 feet in the crawlspace. The other part is about 5-6 feet higher than the basement side. It looks like they did not damp proof the crawl space side. When it rains, I don't see any standing water on the excavated part however on the higher area, the concrete block wall looks like it is damp up to 7-8". I don't see the actual water but the whole soil is damp.
I put a hygrometer in the crawlspace and the humidity reading reached 93% so I want to do something about it. I am thinking about dryspace which is similar to the clean space system. I however am not sure if I need to do something first about the moisture. Also, the house is 25 years old and it never had problems with mold but after following some advice on the internet and closing the vents, a year later and I can see traces of mold on the fiberglass. I am interested in your opinions about what I should do.

If they "INTERNET" said to keep vents closed all the time them you had gotten Bad Advise...

You touched on a lot of situations here. First off check the grade out side for water runoff. Min slope away from structure is 10' Also check gutters and down spouts. Now for the complicated part.

All crawl spaces should be cross vented. Sounds simple yes. Vents open in summer, closed in winter. BUT. The "water" part needs addressed. I'm a stickler for sealing from the grade side of block. A "Dry lock" paint inside will keep too much moisture in the block cavities and could affect the floor plates in a crawl space. New code for crawl spaces/basements is install 3" PVC for radon gas if it shows up.

The Floor insulation in that area could be an issue with that much moisture under it. Just 5% of moisture in Fiber insul causes it to loose 90% of its properties. Sorry for going on. Do the following for a proper job if possible.

1, Check grades/gutters/downspouts location
2. Check floor insul if you have any for Heavy moisture
3. Test dig perimeter of block for crawl space to check for Sealer. If non e, Bingo that needs done. Get back if thats the case.

You can also Use PVC and power vent the crawl space if necessary and set it up as a "radon Vent and kill two birds with on stone to rid the excess moisture.

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Originally Posted by 21boat

If they "INTERNET" said to keep vents closed all the time them you had gotten Bad Advise...

You touched on a lot of situations here. First off check the grade out side for water runoff. Min slope away from structure is 10' Also check gutters and down spouts. Now for the complicated part.

All crawl spaces should be cross vented. Sounds simple yes. Vents open in summer, closed in winter. BUT. the "water" part needs addressed. I'm a stickler for sealing from the grade side of block. A "Dry lock" paint inside will keep too much moisture in the block cavities and could affect the floor plates in a crawl space. New code for crawl spaces/basements is install 3" PVC for radon gas if it shows up.

The Floor insulation in that area could be an issue with that much moisture under it. Just 5% of moisture in Fiber insul causes it to loose 90% of its properties. Sorry for going on. Do the following for a proper job if possible.

1, Check grades/gutters/downspouts location
2. Check floor insul if you have any for Heavy moisture
3. Test dig perimeter of block for crawl space to check for Sealer. If non e, Bingo that needs done. Get back if thats the case.

You can also Use PVC and power vent the crawl space if necessary and set it up as a "radon Vent and kill two birds with on stone to rid the excess moisture.

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"Min slope away from structure is 10'....." What does this mean please?

Slopes are measured by either ratio, i.e. "3:1", or percentage, i.e. "1.0%".

To the OP, I had moisture problems in my basement too. I installed gutters, put down moisture barrier, opened up the vents, and even put a half screen-type door on the opening. It needs to have air circulating around down there to dry it out some. Especially in the colder months. It worked for us really well.

You should have a professional check out the exising mold that you already have.

Quote:

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Originally Posted by jmjoseph

"Min slope away from structure is 10'....." What does this mean please? Slopes are measured by either ratio, i.e. "3:1", or percentage, i.e. "1.0%".

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Actually many times slopes are also measured in Distances run no matter what the degree its set at.

Sorry for short Job Lingo. I assumed there is already a graded "slope" away from the structure, but As I see in the Field many slopes are not far enough/Long enough away from the structure to be effective. i.e. 10' Min.

Codes for a slopes distances on finish grades will vary from township to township. Simply put,, " a finish sloped grade must terminate no less then 10' from the structure"