Got mold?

shawn said:
Remember, a dehumidifier is basically just a little space heater.
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No.

A dehu has an evap coil that gets below the dew point temperature to physically remove moisture vapor from the air and drain it as a liquid to outside the space.

Yes due to total energy it does heat the air slightly, which is good for drying because warm air can hold and transport more moisture than cold air, helping the dehu.

A space heater would lower the humidity by heating the air potentially above the Dew point, but would do nothing to actually remove any moisture from the air.


Typically most dehus in crawlspaces are installed to get enough drying capacity to dry out an already wet crawlspace. Most of the time with these, a similar conditioned only space doesn’t have he drying capacity. They only have the capacity to maintain.

We have done several new houses conditioned only, no dehu, that have worked well but take a few extra steps during construction to make sure they are correct from the start. It can definitely be done, but takes more from the GC and subs to be done correctly.

If sealed well, a smaller dehu should be used to save energy over a larger unit, and/or using HVAC air to condition the space, if it requires that much larger of a HVAC unit.

There are several times of the year that conditioned spaces don’t control humidity well due to weather cycles.

I haven’t seen any data to support a desire to have a positively pressurized crawlspace in regards to indoor air quality, but I’m open to the idea if it can be backed up for good reason.

I still do not like mixing house air and crawlspace air, but that’s just my .02.
 
BRUISER said:
Had a guy come to my house today to get me a quote so we will see.

but he checked my joists and they were at 16% is that high?

I currently only have plastic down on half the dirt floor and I have terrible water issues that we believe we found the issue and will seal if he does the job.
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9-11% is ideal for a closed/conditioned space.

16% to me is acceptable for this time of year, but I’d be looking at the types/amount of mold growth on the wood for evidence of it being higher at different times of the year, even though this is the peak season.

If you want me to look over his quote to fix the crawlspace, email it to me and I’ll give you an honest opinion of it.

I’m guessing you keep the tstat a little warmer?

Water intrusion and movement can undermine the foundation and can be separate from crawlspace moisture as there is little energy available under the house to evaporate it and transport it up to the joists.

Condensation on ductwork and joists from moisture laden air, and surface temps below the dew point are the major concern to wood moisture content.
 
Mac5005 said:
A dehu has an evap coil that gets below the dew point temperature to physically remove moisture vapor from the air and drain it as a liquid to outside the space.

Yes due to total energy it does heat the air slightly, which is good for drying because warm air can hold and transport more moisture than cold air, helping the dehu.
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Damn, calling me out for a 3yo post? :flipoff2:

Nowadays, I say dehumidifier to handle high humidity if/when it happens. But they're basically 1500w space heaters because the evaporator coil and the condenser coil are both inside the space, so what heat is generated is just rejected into the house.
 
shawn said:
Damn, calling me out for a 3yo post? :flipoff2:

Nowadays, I say dehumidifier to handle high humidity if/when it happens. But they're basically 1500w space heaters because the evaporator coil and the condenser coil are both inside the space, so what heat is generated is just rejected into the house.
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Guilty lol.

Never even looked at the dates hahah. Flipgotcha
 
Just looked thru this again. Man this was mind blowing. I don’t miss that job!
 
I'm glad this thread came back up because I'm gonna brag a little about what I've been up to. Our house was built about 12 years ago and during construction it began to rain every day. It got so bad, the floor joist in the crawl space began to mold. I had a company come out and clean everything but they didn't insist on a dehumidifier and at the time I didn't know any better. I installed a crawl space dehu later but mold had already taken back off a little. Fast forward to a couple months ago when I decided to encapsulate the crawl space. I looked at all the mold remediation products but decided to use white vinegar instead. It's amazing stuff and I'm looking for all the bang for my buck or bucks. I got a pump up sprayer and went to work. I could spray both sides of 6 floor joist before the vinegar dried. I pulled the insulation back and sprayed all that area too. After those 6 dried, I re-sprayed those same 6 and wiped each one with vinegar soaked rags. Before anyone reminds me that I should remove the old floor joist insulation and insulate the walls instead, I decided not to increase my termite infestation chances and stick with the insulation in the floor. The very little mold in the original insulation would turn black after the vinegar hit it and die. Let me say here as a disclaimer, vinegar will eat the skin right off your tender areas and cloud your vision. Salve, lotion, and eye drops were used in abundance until a full face respirator was purchased and rain suit pants were worn. Anyway, I put down virgin 12mm glossy white plastic and drilled holes every 16 inches along the walls to attach it to using the "christmas tree fasteners". I drilled each hole 8 inches from the top of the block. This allowed me to have a 2 inch flap of loose plastic above the fasteners to use caulk to seal the plastic to the walls. I wanted to use radon approved caulk but the supply had dried up so I used some other grey caulk. I would have used double sided butyl tape but that would have increased my cost by about $400 and I drive a Ford and a Jeep so I don't have money to burn. I installed a Aprilaire dehu and plumbed the pump to an outside drain line. I got the 12 mil vapor barrier and dehu from Crawl Space Ninja's and everything is working perfectly. I even plumbed in the old dehu that Mac5005 suggested I buy. (Sorry I'm not cool enough to know how to link that to you.) It was quite a job for an old fat guy with 2 torn rotators and 2 missing ACL's. Oh and the hemmoroids were burned off from sitting in the vinegar so that's a plus.
 
thebrotherinlaw said:
I would have used double sided butyl tape but that would have increased my cost by about $400 and I drive a Ford and a Jeep so I don't have money to burn... I even plumbed in the old dehu that Mac5005 suggested I buy. (Sorry I'm not cool enough to know how to link that to you.)
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:laughing: and just type @ before the username @Mac5005
 
77GreenMachine said:
So some of you know I do disaster clean up for AdvantaClean. Today I seen the worst flood/mold problem I've seen so far. This house belonged to the current owners parents who died back in October. The house sat vacant and no one went there from the beginning of November to just last week. The basement had flooded due to the pipe from the well to the pressure tank bursting, and the sump pump not working. The lady said "we've always had some water and a little bit of mold but never like this". The water line can be seen in the pictures. The water was up to the windows, everything was floating and the water is estimated to have been there since late November to when it was pumped out last week. I could only go to the bottom of the stairs since water was still 5" deep thru the whole basement. These are the only pics I got but will add more in the morning as we are pumping the rest out right now. Rain water is also coming thru the foundation so that's why there is another 5" even though it was pumped out last week.

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This is what I found when I opened the door to the basement.

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Note the water line

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The curtains in the window looked like they were cut straight across but that's the water line. That's some nasty water!

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Check out the door to the left in the lower center of the picture. There is another door adjacent that has mold growing downward from the top of the door frame!
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That's all I got, I can't wait to add more pictures when I get in there to get my crew started in the morning. Glad I'm paid well and don't have to do the bulk of the work or else I may be looking for work, this place is gross!
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I didnt know that's what you did, I wondered...
 
R Q said:
What do you do now?
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Outside sales rep for a construction materials distributor. I manage about 120 accounts and help problem solve, consult, write warranty approvals (or rejections) and more. I seem to wear many hats these days. Been here 7 years exactly as of yesterday.
 
thebrotherinlaw said:
I've heard that to get the perfect house we need to build it three times. I think that's just about spot on. I would change several things about our current house.
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your married, a perfect house does not exist. Single a nice shed, fridge, and hot plate is plenty.
 
ckruzer said:
why?
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I don’t like plumbing being ran in concrete. Anything that happens becomes a huge expense to fix. If you ever want to change something like add/remove a wall, or do an addition it’s much harder to route electrical, plumbing and HVAC.

And the big reason is if you have water leak from a pipe in a wall, or washer or fridge, it can flood the whole house. I’ve done way too many jobs where we removed the flooring and 3’ up of the sheet rock in an entire 1500sqft home over a water leak in a bathroom on one end, vs dozens of jobs where the water just messed up 1 room, maybe a little more but ultimately ran into the crawl space. Much less work and cost to repair that vs a slab house.
 
77GreenMachine said:
I don’t like plumbing being ran in concrete. Anything that happens becomes a huge expense to fix. If you ever want to change something like add/remove a wall, or do an addition it’s much harder to route electrical, plumbing and HVAC.

And the big reason is if you have water leak from a pipe in a wall, or washer or fridge, it can flood the whole house. I’ve done way too many jobs where we removed the flooring and 3’ up of the sheet rock in an entire 1500sqft home over a water leak in a bathroom on one end, vs dozens of jobs where the water just messed up 1 room, maybe a little more but ultimately ran into the crawl space. Much less work and cost to repair that vs a slab house.
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Nevermind the efficiency loss of the HVAC in the attic.
 
awheelterd said:
Nevermind the efficiency loss of the HVAC in the attic.
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Another good point. It could be out on the interior but that wastes space. The attic is terribly inefficient and Lord forbid it build up and leak. @BigClay knows all about that!
 
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