Latest crawlspace upgrade

[Donald]

So vapor barrier on the floor only or up the stem walls? Do you still have crawlspace venting to the outdoors?

It's covers 95% of the dirt floor. Nothing on the block walls.

Crawlspace vents are covered with rigid foam board insulation.

I am considering getting Bora foam board attached to the walls and then sealed to the floor.

 

[Donald]

Too low and you will get dry rot. We all have our interests I guess. Not sure the purpose of needing humidity lower than the outside air in most places. Drawing air through the crawl space will keep things dry. I do not think sealing off the crawl in your area is needed.
However, Im not disputing what you want to do as a project. I just think there are efficient ways to keep mold and moisture in control.
Maybe if you lived in Florida or something I would feel different but that doesnt matter to you. just discussing.

https://crawlspaceninja.com/blog/what-should-humidity-be-in-a-crawl-space/

I agree with crawlspace ninja that 45 to 55% is ideal. Most crawlspace dehumidifiers have the lowest setting you can select at 45%. Maybe 40%.

But I think this is kind of a rough number to aim for. Not sure how accurate the RH sensor in the dehumidifier is. Or how accurate the Aeotec smart home RH sensors I have are. But I have two of them. I also have two smart water sensors on the floor to detect water on top of vapor barrier. Then there is the large crawlspace with a dehumidifier in one spot. How about crawlspace areas far away from the dehumidifier? I have some fans but have not installed them yet. Are they needed?

But having a crawlspace with dehumidifier gets little attention by most homeowners. Maybe the HVAC guy checks it when/If he services the air handler in crawlspace. Kind of how most drivers treat their car engine. Minimal attention. Do they have a remote RH meter in house. Do they check it? If they check the dehumidifier and hear it running do they assume it's working? Maybe only fan running and compressor is broken. Dehumidifier has a filter. Does that get changed? Many installs have a condensate pump. They can clog or fail.

 

[Donald]

We've got a foundation crawlspace in our beach house. It's got 4 temperature sensitive mechanical vents. The duct work for the downstairs got taken out by Hurricane Sandy and was replaced shortly thereafter. Had fire and bug retardant foam insulation sprayed on the joists and subfloor. It immediately reduced moisture/humidity levels inside the house by 90%, if not more. No encapsulation...just sand and cobwebs. No issues of rot whatsoever. House was built in 1979 and it's in a flood plain but Sandy was the only flooding in 15 years of ownership. Older CCA PT still plates. HVAC is elevated on a PT deck attached to the house at about 40".

The issue I have heard with foam insulation sprayed on the joists and subfloor is it hides plumbing leaks. Like a toilet or sink dripping or leaking. If I had a leak I will get water on vapor barrier and hopefully one of my water leak detectors will pick it up.

 

[BMWTurboDzl]

It's covers 95% of the dirt floor. Nothing on the block walls.

Crawlspace vents are covered with rigid foam board insulation.

I am considering getting Bora foam board attached to the walls and then sealed to the floor.

Ah. I would add it up the stem walls and then tape it to the plastic on the floor. That would significantly cut back the run time.

 

[Donald]

Ah. I would add it up the stem walls and then tape it to the plastic on the floor. That would significantly cut back the run time.

The Bora foam insulation board is my first things to get done.

 

[Cropduster172]

The issue I have heard with foam insulation sprayed on the joists and subfloor is it hides plumbing leaks. Like a toilet or sink dripping or leaking. If I had a leak I will get water on vapor barrier and hopefully one of my water leak detectors will pick it up.

Water pipes run below the insulation. It's not that thick.

 

[Donald]

Water pipes run below the insulation. It's not that thick.

I am thinking a leak around the toilet flange.

 

[Cropduster172]

I am thinking a leak around the toilet flange.

Yeah but that can be repaired from the top down... Or in the bathroom itself.

 

[Donald]

Yeah but that can be repaired from the top down... Or in the bathroom itself.

The question was more that the problem would not be found for awhile because the foam would hide the leak.

 

[alarmguy]

The question was more that the problem would not be found for awhile because the foam would hide the leak.

If one was to choose foam, it could always be installed under living areas with no plumbing which would still compromise a significant part of the home. Only if one wanted to choose it and that was the only thing holding them back.

 

[Cropduster172]

The question was more that the problem would not be found for awhile because the foam would hide the leak.

Yeah but a leaking toilet from the flange or wax ring usually causes the toilet to run at least intermittently and you usually see a noticeable increase in your water bill.

 

[Crystalanta]

Sealing off vents made a huge difference in keeping moisture down in my crawl space.

 

[Crystalanta]

Sealing off vents made a huge difference in keeping moisture down in my crawl space.

I went with crawl space encapsulation a couple of years ago, and it's been one of the best upgrades I’ve done. The humidity used to creep up in the summer, making everything feel damp. Now, it stays dry year-round, and I’m not dealing with musty odors or worrying about mold near the floor joists.