As someone who lives in ND. I’m laughing at the thought of someone in Atlanta talking about the floor being cold and drafty lol

If you want to insulate it use Kraft face batts. As for it being ventilated. I’m sure it to help with the dampness. Are crawl spaces up here are not usually vented. But the should have the floor covered with plastic. If it’s not concrete

DISCLAIMER - I'm no expert. But all of the research I've done has pointed to completely encapsulating the crawl space, and only insulting the perimeter. So perimeter beam covered in plastic (they make 2-sided epoxy tape and plastic anchors for this, you drill holes as you go with a hammer drill and small bit, every 18" or so and tap in the fasteners, the epoxy tape is 2-sides and goes along the top of the perimeter beam). Piers get the same treatment, like a foot above the dirt. The perimeter plastic folds out onto the ground/floor a bit, and you roll out a heavier plastic and tape the whole mess closed. it's a white plastic with a grid of fibers molded in to make it very tough. Then insulate the perimeter with foam boards. Biggest issue is joist bays, you can cut and sort of friction-fit pieces in those, even use some spray foam to lock them in - just don't do anything that prevents a termite inspection or hides termite tunnels. And then totally seal up the vents. The idea is you make the whole space dry and sealed. You may want to insulate the floors a foot or so out from the perimeter as well. A lot of this info came from the EPA's web site.

Extra-credit is put some exhaust fans in some of the vent openings, there are fans made to fit the various sizes. they have sensors and only turn on when temps get very low or humidity gets high. Because older homes' floors aren't sealed really well, the fans suck some conditioned air "down" into the crawl space and out the vents, so when it's very cold, the crawl space gets warmed up a bit, and thus your floors are warmer; when it's warm and humid, some of your dry AC'd air is passed through the crawl space and out the vents, keeping it extra dry.

I do a lot of marketing work for a mold remediation company, and they consider encapsulation + fans kinda the gold standard. About half of my crawl space has maybe 10" clearance below the floor joists, so it was a BITCH to seal it up, but it's held up for a decade - I still need to do the fans sometime.

What you want to do is google info on proper methods for basement encapsulating. It will give you the info to properly close off the crawlspace to the exterior elements while keeping it safe. You’ll need a dehumidifier.

We have a 1927 home. It has a daylight basement that covers not quite half of the house, so there’s an L shape to the rest of the basement area and it’s just crawl space but with decent head space when the ground is level. So I excavated dirt out by the bucket and raised my front yard for drainage. I got more than half the crawlspace levelled out.

I then encapsulated it. This cut down the draft and cold inside the house so much you can not even believe it. I even insulated the floors prior!

So now my crawlspace is about half way levelled, so I set out to find free file cabinets, the wide kind. I got a bunch free from an office closing. I lined the crawlspace walls with them. They’re something like 50ish inches tall and 4 drawer. So now I have a massive amount of storage space for totes and stuff but also I have tons if metal drawers that close tight to keep critters and dust out.

It was a lot of work but our area is ridiculously expensive, and our house is small. So I have to utilise all the space I can.

My next big project after our kitchen/living room/dining room remodel is done is to build a bookshelf in our hallway that will be a secret door to a ladder. I’m going to build a secret media room in our attic space and it will be 100% hidden.

I'd recommend that your first step is to re-do the plastic. Find some 15 mil somewhere (or similar thickness) and spread it out over the entire surface and even up the concrete walls. This helps to keep down any moisture seeping up from the ground. Tape all seams.

Next, seal all holes through that subfloor with expanding foam and/or zip tape (or similar). Also, seal any air gaps around the sill plate.

Next, spray foam IS the best in a lot of ways. It would cut down on any draftiness by 99.9% and increase the warm feeling of that floor by a ton. BUT - it's expensive. You wouldn't need to do it at full depth to get desired results. But 4-8 inches would be good.

If spray foam isn't in the budget (call some local places), go with some r-21 to r-30 fiberglass insulation. Faced or unfaced it probably doesn't matter too much as long as the humidity stays low-ish in that crawl space.

I'd also recommend getting an accurate hygrometer down there for a week or two to see what the levels of humidity are. If they're consistently low, you can probably stop here. If they are consistently above 60% or so, I'd recommend a dehumidifier that has it's own pump so you can just turn it on and not have to fuss with it when dumping it out.

I’m in SE Pennsylvania and just had our small crawlspace insulated/encapsulated over the summer. This is what they did

1. Put in a sump (get a little bit of water, not much. It hasn’t ran yet)
2. Put down dimpled plastic liner on dirt floor
3. 2-inch foil faced rigid foam insulation on walls with the plastic anchors into block walls
4. A thick plastic over top of the dimpled floor
5. Tape at every seam

One thing to take into consideration that many people don’t think about. If you have linoleum or other moisture impermeable flooring in the kitchen, you do not want to put something directly on the ceiling of the crawlspace below that flooring. Floor joists need to breathe. If you add foam directly to the ceiling of the crawl space (the area below the kitchen floor) you are creating a situation where the wood will rot. Same goes for insulated batting. If you use insulated batting, it is only going to turn moist from the dirt below. Batting does not work well in a crawlspace area with a dirt floor. It is usually suggested to insulate the foundation exterior walls versus the ceiling of the crawlspace to avoid trapping, moisture, causing mold.

You do not want batts in the floor joists overhead. It's difficult, they don't stay put, and a comparison of the surface areas of floor vs perimeter foundation wall is illuminating here.

It will require 3-10x MORE insulation to do the floor than it will to do the foundation. For all that extra effort and expense, what do you get? You will have insulated the boundary with the SMALLER temperature difference (crawl-interior) rather than the larger one (crawl-exterior).

Since heat loss is proportional to temperature difference, that means you have spent more and worked harder to achieve a less effective insulation job.

The way to do it is to encapsulate the crawl with plastic bonded to the foundation walls. Air seal, use rigid foam inside the foundation, leave a termite inspection gap.

There are many sources on how to do this right. Read those. The very best energy efficiency renovations do it this way.

Vented crawls with overhead insulation are so dumb it makes my brain ache.

The basics.

• Use a plastic vapor barrier to keep moisture from coming up from the ground.
• If you can, add vents to the other side of the crawlspace. This will help keep moisture at bay.
• Seal all the perforations between the conditioned space and the crawlspace. This will help with air and moisture exfiltration.
• Insulate your plumbing as the heat coming from the house will be reduced, so the risk of a frozen pipe goes up. Yes, even in Georgia.
• Use R30 unfaced batts/rolls as they will fit between your floor joists and the added cost is worth the extra R value. You can use rigid wires designed to fit between joists to keep the insulation up close to the subfloor.

1. Redo the vapor barrier on the ground, 8mil+ visquine works
2. Buy a spray foam gun and some cans of foam, about $70, and spray those rim joists. That is where your outside air is entering the crawlspace. Spray all 4 sides, especially where the rim joist contacts the sill plate (this can be a tricky spot, buy the professional spray gun)
3. Use the spray foam to glue the edges of your vapor barrier to the wall, let that foam cure for about 30 seconds before you stick the barrier to the wall, for maximum stickiness
4. Use that spray foam gun you bought to “glue” blanket insulation sheets to your crawlspace walls. I recommend the “all season” foam or something with good adhesive properties. We found the best way to do this is spray the foam all over the insulation, let it cure for about 30 seconds, and then stick it to the wall. If you stick it to the wall right away the foam might just feel off and you wont get a good bond

Source: I work for an insulation contractor and have been doing this daily for 2 years now

I used comfort-therm wrapped insulation and would likely never use anything else (unless I was blowing it into an attic or something). Almost no itchiness and FAR less airborne fibers.

https://i.imgur.com/ZbE7tqe.jpg

Bodies

Leca beans on top of the plastic should work.

One foot of beans roughly corresponds with 10cm Styrofoam for insulation values.

I'm confused. "Heat loss" + "Atlanta" = free cooling ~10 months of the year? Maybe just get some house slippers?

I would spray foam the cavities inside the floor joists over the walls. Glue some 2" foam board to the walls after putting down heavy plastic. Let the plastic come up the walls a bit so foam board will pin down edges. Foam seal gaps and seams, foam seal any penetrations. Then add unfaced fiberglass to joists.

Greetings from Finland. I'd go for foam glass bubbles for easy application and healthy result.

here is first link about the stuff in English.

>GEOCELL Foam Glass Bubbles are versatile, insulating beads for use with or without a binder (such as natural hydraulic lime or cement). In addition to having no negative impact on health, using foam glass bubbles guarantees excellent insulation with the highest fire safety and ease of use.

Thermal Conductivity – 0.07 W/mK.

Supplied in 100 litre bags.

2-4 mm size beads.

LOOSE FILL THERMAL INSULATION

GEOCELL® foam glass bubbles have excellent free-flowing properties due to their spherical shape. As a result, the small glass beads easily fill voids in beamed ceilings, floors and cavity walls for improved thermal insulation. Furthermore, it’s very easy to cover pipes and cable ducts. Use environmentally friendly, lightweight glass bubbles in many of the same applications as vermiculite but in addition have the significant advantages of being:

non-absorbent.

non-capillary.

vapour permeable.

fire resistant Class A1

inert, safe and dust-free.

made from recycled glass (not produced from virgin materials).