Commercial dehumidifier in crawl space

[RalphVa]

In our 7th year after encapsulating our crawl space underneath the family room and laundry room, we started experiencing odor and it affecting my wife this year. It has been traced to bacteria formation underneath the encapsulation. The expert who diagnosed this recommended a commercial dehumidifier, Santa Fe or AprilAire. We went with the Santa Fe because it is more efficient even though about $100 more. Bought their 70 pints/day one.

There's a remarkable difference between it and the run-of-the-mill department store dehumidifier. We tried one of those in our first year of encapsulation. It was inadequate (at the same 70 pts/day) because it grossly heated up the crawl space and didn't seem to lower the humidity much. We went to about 3 different fans located at various places in the crawl space plus a normal dehumidifer in the adjacent utility room. This worked well for 6 years, until this year.

The exhaust from the Santa Fe is only about maybe 70 F. I figure the thing has enough air flow such that the cold coil probably only cools the air maybe 5 F and then the hot coil reheats the air 15 F: 60 F down to 55 F and then back up 70 F. I could do a whole lot of calcs to prove this, as this is kind of work that I did as a chemical engineer, but figure I'm pretty close in my guess.

Highly recommend the Santa Fe. The compressor is so quiet that you cannot tell when it comes on. You just have to watch for the water being condensed out on the cold coil.

Ralph

 

[RalphVa]

We had our friend who is a handy man take out 3 concrete blocks to enlarge the opening to the crawl space. My wife hung her toe coming out of the smaller space and bounced onto the file cabinet and then only the concrete floor of the utility room. It pulled some muscles around her ribs and was painful for a couple weeks.

Here's the enlarged crawl space opening.

Ralph

 

[RickB]

We are having an encapsulation done this month. Both contractors we interviewed suggested Aprilaire as their current recommendation but both have used Santa Fe in the past and if we preferred would use that brand without reservation.

 

[RalphVa]

That unit sitting on a shelf just inside the crawl space is an air purifier. It didn't entirely do the job: thus the Santa Fe. The air purifier uses a Merv type filter ahead of an activated carbon one.

The Santa Fe has a Merv 13 filter on its air inlet. If it also had an activated carbon one, we could junk the air purifier.

Ralph

 

[PsRumors]

We've been using two Santa Fe units for about 3 years now, one in our garage and one in the encapsulated crawl space. They work very well.

 

[user.69169]

Why not just kill the dang mold and solve de problem for 5-7 years?
Whille you at it spray all wood & everything above de pool liner too cause you can bet it got mold growing into it.

 

[RalphVa]

Wife wiped down all surfaces with bleach solution in utility room and entire encapsulation. She even removed all the floor joist insulation. (Don't need it with sealed encapsulation, e.g. not vented to outside.) Found a little bit of mold on the insulation.

The bad stuff is on the back side of the encapsulation in contact with the ground. Cannot get to it. Gotta kill it by drying it out.

No mold evident on any of the wood.

Ralph

 

[Frankenkubota]

The guy who drew the plans for my house and shop asked me for 3-4 priorities.

1. Hip roofs

2. 10 ft walls, 2x6

3. NO CRAWLSPACE!

I just spent way too much money on a foundation I call my Rock of Gibraltar. Solid concrete! The guy said it’s way beyond code and a waste of money.

My last crawlspace was literally that. I had to put tools in a bag and tie them around my belt because you had to go in on your belly! Never ever again!

That should, imho, be against code.

Snakes love crawl spaces.

 

[Sigarms]

The guy who drew the plans for my house and shop asked me for 3-4 priorities.

1. Hip roofs

2. 10 ft walls, 2x6

3. NO CRAWLSPACE!

I just spent way too much money on a foundation I call my Rock of Gibraltar. Solid concrete! The guy said it’s way beyond code and a waste of money.

My last crawlspace was literally that. I had to put tools in a bag and tie them around my belt because you had to go in on your belly! Never ever again!

That should, imho, be against code.

Snakes love crawl spaces.

Try installing an HVAC system or retrofitting ductwork in a a crawlspace.

Up north, they think package units are for sitting on roofs and have no clue that a package unit can be put on the side of a house and ductwork is run UNDER the house:laughing:

When we got married in NC and looking for a home, one requirement was a basement (which is more rare than the norm here IMO).

For the last 15 years or so have been using a Aprilaire dehumidifier. The unit runs constantly in the summer, tied to the first floor system. On average, brings all three floor levels down about 5-10% in RH with the first floor generally never getting over 42% RH, which leaves me running the t-stat at around 77F in the summer.

 

[RalphVa]

The guy who drew the plans for my house and shop asked me for 3-4 priorities.

1. Hip roofs

2. 10 ft walls, 2x6

3. NO CRAWLSPACE!

I just spent way too much money on a foundation I call my Rock of Gibraltar. Solid concrete! The guy said it’s way beyond code and a waste of money.

My last crawlspace was literally that. I had to put tools in a bag and tie them around my belt because you had to go in on your belly! Never ever again!

That should, imho, be against code.

Snakes love crawl spaces.

Wife just found a snake skin in the crawl space. None was there when she wiped it all down. Gotta be a snake in there somewhere. We had one get hung up in our main HVAC blower once.

Our crawl space is hunched over walk space (for the wife, not me) until ones gets to under the laundry room. Then it's a comfortable "walk" on all 4s.

Didn't get a vote. It was there when we bought the place: bare earth. Encapsulated (which I think now is required) in 2013.

Ralph

 

[RalphVa]

Try installing an HVAC system or retrofitting ductwork in a a crawlspace.

Up north, they think package units are for sitting on roofs and have no clue that a package unit can be put on the side of a house and ductwork is run UNDER the house:laughing:

When we got married in NC and looking for a home, one requirement was a basement (which is more rare than the norm here IMO).

For the last 15 years or so have been using a Aprilaire dehumidifier. The unit runs constantly in the summer, tied to the first floor system. On average, brings all three floor levels down about 5-10% in RH with the first floor generally never getting over 42% RH, which leaves me running the t-stat at around 77F in the summer.

View attachment 672024

We had duct cleaning done. They said the plastic ductwork needed replacing in the crawl space. Did that. On ours, it's not that much of a problem. Probably easier in there than going up in the attic and doing the ones there. Real challenge would be to replace the ducts in the regular basement area.

Ralph

 

[Sigarms]

We had duct cleaning done. They said the plastic ductwork needed replacing in the crawl space. Did that. On ours, it's not that much of a problem. Probably easier in there than going up in the attic and doing the ones there. Real challenge would be to replace the ducts in the regular basement area.

Ralph

I've got to ask, what kind of plastic ductwork? The only product I'm familiar with is for is generally used for slabs under the house, which I most likely wouldn't touch with a 10' pole if there is a problem looking at 20 years from now. Since a crawl space is unconditioned, perhaps I'm missing the boat on something (wouldn't be the first time:laughing.

And yes, to replace my attic LP/AC system with a dual fuel system along with lineset was a pain in the butt, it took a total of 54 man labor hours to deal with everything (3 guys including me 2 full days).

 

[RalphVa]

I've got to ask, what kind of plastic ductwork? The only product I'm familiar with is for is generally used for slabs under the house, which I most likely wouldn't touch with a 10' pole if there is a problem looking at 20 years from now. Since a crawl space is unconditioned, perhaps I'm missing the boat on something (wouldn't be the first time:laughing.

And yes, to replace my attic LP/AC system with a dual fuel system along with lineset was a pain in the butt, it took a total of 54 man labor hours to deal with everything (3 guys including me 2 full days).

I don't know what to tell you. It seems to be pretty much standard around here. The main supplies and returns are metal, but the off takes from them are pretty much all insulated plastic.

Ralph

 

[user.69169]

Wife wiped down all surfaces with bleach solution in utility room and entire encapsulation. She even removed all the floor joist insulation. (Don't need it with sealed encapsulation, e.g. not vented to outside.) Found a little bit of mold on the insulation.

The bad stuff is on the back side of the encapsulation in contact with the ground. Cannot get to it. Gotta kill it by drying it out.

No mold evident on any of the wood.

Ralph

Tell you a thing r 2 from a boy grew up in a swamp, you choose to learn or not.
Bleach is a terrible way to kill mold, vinegar is too and so is dryin de mold out.

What you got there is kind of a liner pool inside concrete walls wid a well under and maybe even around de liner.
Now I know all about de professional contractor who assured you and warrantyed and showed you pictures and sweet talked, met a few of dem myself. He probably belongs to some group and is a member of the BBB, he got money AND YOU GOT MOLD!

Any time you lay sheet of plastic on dirt any water in de dirt gonna come up to plastic and condense. You do it in Nevada desert you get water.
Job done right would have collector between dirt and de plastic. Little bit of proper digging of de dirt takes all de water to de collectors and off to a crock so it can be pumped away.

You got Mold instead, took a few years, and now you got it its der to stay.

So, how you kill it? Baking Soda, or Washing soda. Either one kills mold dead AND leaves behind a salt dat keeps a new crop from coming in quick. Nice thing is you can blow soda between de liner and de dirt real easy.

Same soda will kill moss on de roof and walls and keep it away a couple years too.

 

[Sigarms]

I don't know what to tell you. It seems to be pretty much standard around here. The main supplies and returns are metal, but the off takes from them are pretty much all insulated plastic.

Ralph

Out of curiosity, if you ever get a chance, please post a pic

Still a little confused (easy on my end). I've really ever known take offs being metal on ductwork, including ductboard. Aware of plastic diffusers, but never seen a plastic take off.

 

[oosik]

The screened vents in my foundation walls provide sufficient air flow to keep the basement dry. I still don't know how the small, loud-mouth, green frogs get in the basement.

 

[RalphVa]

Tell you a thing r 2 from a boy grew up in a swamp, you choose to learn or not.
Bleach is a terrible way to kill mold, vinegar is too and so is dryin de mold out.

What you got there is kind of a liner pool inside concrete walls wid a well under and maybe even around de liner.
Now I know all about de professional contractor who assured you and warrantyed and showed you pictures and sweet talked, met a few of dem myself. He probably belongs to some group and is a member of the BBB, he got money AND YOU GOT MOLD!

Any time you lay sheet of plastic on dirt any water in de dirt gonna come up to plastic and condense. You do it in Nevada desert you get water.
Job done right would have collector between dirt and de plastic. Little bit of proper digging of de dirt takes all de water to de collectors and off to a crock so it can be pumped away.

You got Mold instead, took a few years, and now you got it its der to stay.

So, how you kill it? Baking Soda, or Washing soda. Either one kills mold dead AND leaves behind a salt dat keeps a new crop from coming in quick. Nice thing is you can blow soda between de liner and de dirt real easy.

Same soda will kill moss on de roof and walls and keep it away a couple years too.

There is something between the plastic we see and the dirt, some sort of ruffled black plastic thing. Cannot get under the plastic we see unless we untape around the upper edges. Did some retaping where we enlarged the hole. Old tape doesn't hold as well. I'm not touching the tape in place.

Humidity is down to 47% now. Turned back the humidistat control on the Santa Fe.

Ralph

 

[RalphVa]

Out of curiosity, if you ever get a chance, please post a pic

Still a little confused (easy on my end). I've really ever known take offs being metal on ductwork, including ductboard. Aware of plastic diffusers, but never seen a plastic take off.

Posted a pic earlier that shows some of it. I'll post it again. That duct work you see to the left and goes up above the Santa Fe is the new plastic duct. It's fatter with more insulation than the old (dirty) ducting.

Ralph

 

[RalphVa]

The screened vents in my foundation walls provide sufficient air flow to keep the basement dry. I still don't know how the small, loud-mouth, green frogs get in the basement.

We had vents under there before. Had a mud pit at times around the base of the chimney. Not nice doing any maintenance in there. Think they require encapsulation of crawl spaces in new construction, and those are usually enclosed.

Ralph

 

[Sigarms]

Posted a pic earlier that shows some of it. I'll post it again. That duct work you see to the left and goes up above the Santa Fe is the new plastic duct. It's fatter with more insulation than the old (dirty) ducting.

Ralph

The irony is I was going to say the only thing I really see (because I was looking at that picture as well) was the vinyl flexible duct I assumed (my fault) when you said take offs you were refering to the tab collars that are metal that connect to the main supply and return duct.