What does mold require to grow? - PeachParts Mercedes-Benz Forum

t walgamuth · #1 05-16-2009, 09:21 AM

A house that I designed and built and sold two years ago is built on a very steep hill. On the south side of the house the hill is at places as much as 12' higher than on the north side so water coming down from the hill collects in a low point which has perforated concrete with sand fill which allows water to soak through and down to a perforated drain which is buried at the bottom of the wall.

The folks who bought the house have not kept the weeds from growing there and last night after weeks of rain the water built up in that area and came through the frame wall which sits on top of the concrete basement wall and ran down behind the 2x4 stud wall in the entry way and under the bottom of it into the entry way.

So I got a call last night at midnight and went over and helped get the water level down outside enough that it stopped coming in.

Now I am thinking about what remedial steps to do.

My first concern is to avoid mold growing between the frame wall and the concrete wall. The frame wall is tight against it, is insulated and has visqueen inside the insulation and finished drywall. There is wood trim at the bottom of the wall.

My first inclination is to just put fans in there and keep them there until we are sure every bit of water has evaporated out of it.

There are other architectural/ technical things which I know how to figure out myself that will need to be done too, probably.

Will mold grow in an environment that is damp but not supplied with free air?

davestlouis · #2 05-16-2009, 09:30 AM

I seem to recall that it needs something like 30% moisture and oxygen. As a liability issue you really should have the homeowner call a catastrophic cleanup company and have them clean and disinfect it. I'd hate for you to think it's dealt with then 2-3 years from now find out that black mold has bloomed in the whole wall and someone is claiming a health issue.

cmbdiesel · #3 05-16-2009, 09:35 AM

If water can get in, then enough air can get in as well. The best thing is to dry the area, and eliminate the opportunity for water to enter again. My experience is that mold will grow anywhere it can find moisture and food.(wood, paper, any organic material) Boric acid is an excellent mold killer, if you can get it to the affected area. Sounds like the long term solution is going to be regrading the uphill side, so the water cannot build up. Obviously the drainage system you designed requires someone to give a crap about maintaining it, which seems to be lacking with the current owners. Every house I have built into hillsides (4) was graded in such a way as to channel water coming off the hillside around the house, in addition to having a french drain with perforated pipe buried around the foundation. Gutters also need to carry all the water away from the uphill side of the house.

The only cure for mold is to remove the water.

dannym · #4 05-16-2009, 10:30 AM

I believe it's over 60% relative humidity that mold needs to grow. You can double check at the EPA website.

Danny

t walgamuth · #5 05-16-2009, 02:21 PM

Quote:

Originally Posted by cmbdiesel

If water can get in, then enough air can get in as well. The best thing is to dry the area, and eliminate the opportunity for water to enter again. My experience is that mold will grow anywhere it can find moisture and food.(wood, paper, any organic material) Boric acid is an excellent mold killer, if you can get it to the affected area. Sounds like the long term solution is going to be regrading the uphill side, so the water cannot build up. Obviously the drainage system you designed requires someone to give a crap about maintaining it, which seems to be lacking with the current owners. Every house I have built into hillsides (4) was graded in such a way as to channel water coming off the hillside around the house, in addition to having a french drain with perforated pipe buried around the foundation. Gutters also need to carry all the water away from the uphill side of the house.

The only cure for mold is to remove the water.

Yes. If he straightens out his gutter and keeps the mud and weeds out of the area I believe he will have no more trouble. I am planning to create a scupper or something to provide an outlet other than going over the wall into his entry way.

I am hoping we can get it dried out before the mold has a chance to grow. I'd rather not peel off the drwall in that area and redo all the finishes!

Is there a way to test air quality to see if its growing?

Brandon_SLC · #6 05-17-2009, 02:05 AM

Call Servpro. It will cost a few hundred dollars, but they will get it dried out fast and keep mold from growing. We had a few spots of mold in our house when we bought it. I fixed those myself, wearing a protective coverall and a respirator.

Since then, we have had 4 different interior floods. (1 per year). We have Servpro on speed dial. I don't want mold coming back. You have 3 to 4 days to get it dried out. If they think there is a chance it might not be dry fast enough, like when you wait 3 days before calling, they will spray mildewcide.

Fiberglass wont support mold growth but wood and drywall will. It loves the back of drywall!

cmbdiesel · #7 05-17-2009, 08:05 AM

Quote:

Originally Posted by t walgamuth

Yes. If he straightens out his gutter and keeps the mud and weeds out of the area I believe he will have no more trouble. I am planning to create a scupper or something to provide an outlet other than going over the wall into his entry way.

I am hoping we can get it dried out before the mold has a chance to grow. I'd rather not peel off the drwall in that area and redo all the finishes!

Is there a way to test air quality to see if its growing?

Yep, keeping the water out is essential.

The affected area should be sealed off to the greatest extent possible, and dehumidified. Mold needs 55% humidity to grow. There are a variety of air and surface tests available. I used this site for some decent info when I bought my current house, a repo that had some water issues. - http://www.toxic-black-mold-info.com/ and a NYC page - http://www.nyc.gov/html/doh/html/epi/moldrpt1.shtml

My situation was one of extremely obvious mold growth, so I had no need for tests to determine if it was present. I had to eliminate all leaks, then remove affected drywall and clean underlying studs. Then I baked the house while running a dehumidifier 24/7 for about a month (I had other demo projects to do while everything dried) Then a liberal application of boric acid, and reinstalling drywall. I even mixed boric acid in with my drywall mud and texture, to insure a full treatment.

I would think that if you can get the area dried out, and the humidity down, then you'll be alright. It may be that installing a humidity gauge in that area would be a good idea, in case they get more minor flooding occurrences that go unnoticed.

Whiskeydan · #8 05-17-2009, 08:58 AM

Borax/glycol mix will kill and prevent mold growth however, a less toxic method would be UV light, ozone.

link · #9 05-17-2009, 04:04 PM

I don’t have an answer to the question about mold.

I was involved with a couple of floods recently. A group suggested by the insurance company came in and removed sheet rock, insulation, and low level trim work and molding to expose all the saturated areas to air. They used wet vacs, put several large fans in various places pointed at the saturated areas. Carpets were lifted in areas and fans that are designed to shoot air under the carpets were inserted at about 1 or 2 per 20 x 20 area. They also used several large de-humidifiers – roughly 1 per 20x20 area. These collectively created a fair amount of heat (about 80 degrees) and these ran 24x7 for a week. You could probably get most or all of this from any reasonable sized rental company

After all was dried out, they replaced/repainted the stuff they removed.

They also used tools to detect moisture levels. They monitored moisture in several areas over time.

t walgamuth · #10 05-17-2009, 09:16 PM

Thanks, I think I will see if we have a servepro in Lafayette.

Skid Row Joe · #11 05-17-2009, 10:15 PM

Quote:

Originally Posted by t walgamuth

A house that I designed and built and sold two years ago is built on a very steep hill. On the south side of the house the hill is at places as much as 12' higher than on the north side so water coming down from the hill collects in a low point which has perforated concrete with sand fill which allows water to soak through and down to a perforated drain which is buried at the bottom of the wall.

The folks who bought the house have not kept the weeds from growing there and last night after weeks of rain the water built up in that area and came through the frame wall which sits on top of the concrete basement wall and ran down behind the 2x4 stud wall in the entry way and under the bottom of it into the entry way.

So I got a call last night at midnight and went over and helped get the water level down outside enough that it stopped coming in.

Now I am thinking about what remedial steps to do.

My first concern is to avoid mold growing between the frame wall and the concrete wall. The frame wall is tight against it, is insulated and has visqueen inside the insulation and finished drywall. There is wood trim at the bottom of the wall.

My first inclination is to just put fans in there and keep them there until we are sure every bit of water has evaporated out of it.

There are other architectural/ technical things which I know how to figure out myself that will need to be done too, probably.

Will mold grow in an environment that is damp but not supplied with free air?

Air and water==mold. Air is everywhere, and so is moisture content.

Why would you respond to a midnight call, on a home you sold "two years ago?" That seems odd to me. Is there something blatantly deficient in the home's design and build? -I would hope not.

cmbdiesel · #12 05-17-2009, 10:30 PM

Quote:

Originally Posted by Skid Row Joe

Air and water==mold. Air is everywhere, and so is moisture content.

Why would you respond to a midnight call, on a home you sold "two years ago?" That seems odd to me. Is there something blatantly deficient in the home's design and build? -I would hope not.

Air and water does not equal mold. Mold requires food, just like any other living organism. Moisture content is not everywhere, that's why God invented houses and dehumidifiers, so we don't have to live in a swimming pool.

Some people treat building a home as more than a caveat emptor experience. I would get out of bed at midnight if one of the homeowners in a house I built called with a legitimate problem.

Thread starting post described how the current homeowner neglected the requisite maintenance of drainage.

t walgamuth · #13 05-18-2009, 06:51 AM

Quote:

Originally Posted by Skid Row Joe

Air and water==mold. Air is everywhere, and so is moisture content.

Why would you respond to a midnight call, on a home you sold "two years ago?" That seems odd to me. Is there something blatantly deficient in the home's design and build? -I would hope not.

I was still up (unusual), they live one block from my house, I designed it and built it, I wanted to see exactly what was actually happening, (liability) and they are nice folks who were in anguish thinking that their wall might collapse which is right under their master bedroom (it was not).

I guess mainly it seemed like the right thing to do.

So I turned a potentially big problem into a much more managable problem and they feel we are going to solve it together.

Much better than if they got really frustrated and decided to call their lawyer.

There is nothing blatanty deficient in the design or construction, but the property on that side of the house rises about ten feet in about ten feet so its always going to be something that is potential trouble if something fails.

Not to mention that we have had rain nearly every day for the last month and a half.

t walgamuth · #14 05-18-2009, 07:12 AM

Quote:

Originally Posted by cmbdiesel

Air and water does not equal mold. Mold requires food, just like any other living organism. Moisture content is not everywhere, that's why God invented houses and dehumidifiers, so we don't have to live in a swimming pool.

Some people treat building a home as more than a caveat emptor experience. I would get out of bed at midnight if one of the homeowners in a house I built called with a legitimate problem.

Thread starting post described how the current homeowner neglected the requisite maintenance of drainage.

Thanks.

LUVMBDiesels · #15 05-18-2009, 10:22 PM

When I had a flood in my house the company I called in pulled up with a trailer. In the trailer were two sentral AC units and two propane gas furnaces. They would pull air out of the house and into the trailer run it through the AC units to dehumidify the air and then through the furnaces sequentially to get the air temp up to 130 degrees. They ran this set up in my house for 24 hours and it was as dry as a bone. If you have a small area to deal with, try putting in a couple dehumidifiers and then a kero turbo heater or two to get the temp up over 100 degrees. You could probably reuse this equipment so it is not a single use purchase.