Basement Dampness / moisture

[homelessdespot]

TLDR: Where is the line drawn for Moisture and dampness being a problem in a basement?

Shopping for first house, have never had a basement, lived in on slab raised ranches my whole life. Current raised ranch I'm in, my parents had to do a french drain on the side that was half under ground with block wall to stop the dampness and water seeping in the front. After that, dry as a bone, no musty smell.

So when shopping for houses, I see a lot with basements that are musty and damp. I know basements are supposed to be damp and musty. And I know the current modern recommendation out there is not to ventilate them because you will get more moisture through condensation.

But I've seen places where the damp smell even migrates through the floor into the house. And some places mention "Minor water seepage" during the really heavy rain we had this year. When is the line drawn on a basement that is damp or has water seepage during storm rain? IE. would need some kind of repair like french drains significantly adding to the cost. (This is assuming gutters are functioning correctly). I'm shopping in Norwalk, CT, not looking at houses in flood zones.

 

[rkrcpa]

I would challenge the assertion that "Basements are supposed to be damp and musty".

 

[homelessdespot]

I would challenge the assertion that "Basements are supposed to be damp and musty".

Yeah, I have seen completely dry basements and would prefer that. But seems like most in this region have a musty smell. I'm shopping in a huge price range too so it's not only inexpensive houses.

 

[CKS1955]

I would challenge the assertion that "Basements are supposed to be damp and musty".

Agree. The houses must not be controlling the moisture through the use of a sump, dehumidifier and addressing the source of the moisture.


Jay

 

[engineer2]

use of a sump, dehumidifier and addressing the source of the moisture.

I would add controlling the basement temperature and having adequate air circulation.

 

[homelessdespot]

I would add controlling the basement temperature and having adequate air circulation.

Air circulation or ventilation from outside? Most modern recommendations I see say no ventilation for basements or crawlspaces because it can cause condensation (for summertime).

 

[b-boy]

Generally 2 issues lead to the moldy smell in a basement -

Summertime - Hot, humid air hits cool basement walls causing condensation and eventually mold.

Wintertime - Cold concrete wicks moisture from surrounding soil into less humid basement air. Causes moisture and mold.

Adding ventilation to eliminate the problem, might actually make it worse. In the case of Summer air, you want to avoid introducing more humidity to your basement as it will actually create more water condensation on the walls.

You need a thermal break and a vapor barrier to properly control the movement of moisture in a basement. This keeps the humid air from touching cold concrete, and prevents water vapor from wicking up through the concrete.

Add a dehumidifier, and you'll get rid off the stink pretty quickly.

But - if you have water intrusion, all bets are off. That's a separate issue and needs to be addressed first. It's usually not cheap to fix either. The solution is usually to keep water away from your foundation walls using drains and/or soil grading.

 

[engineer2]

I was thinking more for a finished basement. I agree, I wouldn't circulate crawl space air throughout the house. In our subdivision the basements are well sealed poured concrete but still feel damp in the summertime. They were originally unfinished with no basement HVAC. Dampness was mainly due to the cold air settling in the basement. Adding some vents and an air return helped a lot. (An air return can't be in the same room as the furnace.) Better basement heating took care of problems in the winter. Results will vary depending on type and age of construction and where you live.

 

[MFolks]

I remember my late father when I was 6 or 8 years old,digging around the concrete walls of our house's foundation,and applying a sealer(black sticky tar?) it seemed to work as I do not remember our house suffering water intrusion or moldy smells Summer or Winter,in Des Moines Iowa.

 

[justinthurn]

For what it's worth, I have a well sealed finished basement 3 years old. No moisture problems. I put in a 75 gallon saltwater fish tank with no cover this year. In 6 months it has given off enough water vapor to give the old musty basement smell. I started using a dehumidifier, and the smell goes away in 2 days. Just saying the musty smell may not necessarily mean a water intrusion issue and can be managed easily most of the time.

Sent from my SM-G960U using The Garage Journal mobile app

 

[ManOnTheCouch]

If you're looking to buy now, this is your one chance to get it right on this purchase. Stay away from any basement that has ever had flooding or seepage. Sellers will often disclose it but state they have fixed the problem that caused it. Don't believe them. If a basement has flooded once or had seepage chances are it will happen again even if someone has attempted to fix it.

If it's truly a dry basement that has a musty smell just run a dehumidifier and make sure you have air intakes and ducts in the basement as well. This will provide adequate air circulation and rid the basement of humidity.

 

[matt_i]

Definitely a shift in building practices spanning over a century or more.

The exterior wall waterproofing, silt socks, vapor barrier, and pumped sumps are all relatively recent and not always fully applied.

Humidifier will take care of all but the most egregious problems although there's a cost in the units themselves plus the electricity they constantly eat.

 

[Showkey]

Agree with others .....basement should not smell musty.

Ideal Summer basement humidity level is about 50%. Dehumidifier is the tool of choice.
AC works too but basement by their nature are often much cooler than the main home levels. AC can make them too cold and not comfortable.
Measuring the humidity levels is critical.
Winter, basement humidity is rarely a problem once the heat is on.

Prolonged levels 65-80% will cause mold, mildew and funky smells. Organic material like paper, fabric, leather and rubber will start to mold.

Remember relative humidity is relative to the temperature.

 

[The Cobbler]

my basement is 98% wrapped with Delta Wrap below grade,zero musty smell or dampness issues

 

[Bretny]

If you want a dry basement wait until spring then go shopping for one. If you buy a musty one thinking your just going to fix it later could cost you over 10k.

Also water against concrete of any kind can really degrade the wall badly.

 

[foodie]

If you want a dry basement wait until spring then go shopping for one. If you buy a musty one thinking your just going to fix it later could cost you over 10k.

Also water against concrete of any kind can really degrade the wall badly.

Agree with this wholeheartedly. In the spring with heavy rain you will truly see if there are any moisture or seepage issues. I am going through a hell of a time right now with my basement. Never had any issues until we had rain the whole month of June. Water infiltration reared it's ugly head. And yes I am paying close to $10,000 to fix it and insulate it.

 

[kmacht]

Musty smelling basements are the norm in Connecticut during the summertime. The humid air and the cold concrete walls will create it unless you run a dehumidifier or you have a forced air furnace/AC system in the basement turning over the air regularly. What you want to avoid is any house that lists even minor water seepage unless you can verify what was done to fix it properly. Our last house had minor seepage into the basement. It only happened when you got lots of rain in a very short time and usually started coming in a few days after the rain first started. It made it so we couldn't store anything on the floor in the basement and couldn't finish it. I tried all the easy fixes with out success (hydraulic cement at the wall/floor seam, tar sealer, drylok paint, etc) I finally got fed up with it one year and rented a backhoe, dug all around the basement wall that was seeping (back of the house) and installed a proper french drain at the footer running to a sump pump inside whose tub went another 3 feet down. The whole side of the house got backfilled with gravel wrapped in drainage fabric up to about 1 foot from ground level. Since then we never had another leak. I had a few quotes from basement companies to fix the problem and they all were between 15 and 30k. Minor water seepage is either something you want to completely avoid or at a minimum make sure the house price and your budget are adjusted to fix it once you move in.

 

[homelessdespot]

I had a few quotes from basement companies to fix the problem and they all were between 15 and 30k. Minor water seepage is either something you want to completely avoid or at a minimum make sure the house price and your budget are adjusted to fix it once you move in.

You have confirmed my fears haha. Glad I didn't bid on a house that claimed "minor seepage during heavy rains this year", as it wasn't priced appropriately. I may want to restrict my shopping to on slab houses like raised ranches so if water is an issue, digging for a french drain is much less work and cost. Or at least basements that have a walk out so only 1 to 2 sides are buried deep.

 

[Bretny]

Houses with walk out basements generaly dont always have this problem in my area too. At the very least when/if you ever have to do the footing drains they can be exited to daylight this means they work when the power is out, its raining and you would need a sump pump to work the most.