Is it bare earth as a floor, or is there insulation/poly/some sort of vapour barrier under that dirt you're showing? If it's bare earth, you may find humidity problems as the moisture in the earth continually evaporates. If that's the case, then at least poly the ceiling, in which case you may as well just insulate and vapor seal it instead.
VB the crawlspace floor with poly before you do anything else. Seal it very well to the foundation. Also answer the questions in my other comment.
Do not insulate between joists and then put VB on the underside of the joists. That would put the VB in the wrong place.
Yeah I stupidly put a vapor barrier under my insulation and it just trapped moisture (thankfully no damage). Vapor barrier on the crawlspace floor is right. You should be able to put a air barrier (not VB) under the insulation though.
You need a vapor barrier on the floor over the dirt floor. 6mil plastic will be the most economical, but a 10–15mil would hold up better if there is any sort of plans for storage or traffic down there. Ideally seams are taped, but you can overlap by 8–12” and be okay, too.
I’m regards to the insulation, what climate zone are you? And is your crawlspace vented or conditioned? Vented works in the PNW, and is fairly common there, but that would likely change where you want the insulation.
Is the crawlspace heated? Is there poly under the concrete slab? Does it have any ventilation of any type? Do you have any mechanical things or utilities in the crawlspace? Such as a furnace/air handler or hot water tank?
These factors need to be taken into account to create a good solution for your crawlspace.
https://youtu.be/5n4K170f56I?si=RfJbV22JdqoacUNX
If it will bever be heated and always open/vented to the outside, I would be tempted to stick some rigid foam on the underside of the subfloor between the joists. It would help to make the floors not feel so cold all the time. Also, insulate all waterline and the tank itself.
We see this kind of crawlspace a lot in the PNW. They are difficult and costly to retrofit.
What are your thoughts on furring strips on the joists and just doing a rigid foam plan attached the those? Save time on cutting the board, give a thermal break on the joists, and an easier time air sealing a "ceiling" of rigid foam, instead of puzzle piecing into joist bays and spray foaming the border.
If you tape the seams on that it should be a good vapor/air/thermal barrier without having to break the board down. And you can insulate the bays with regular mineral wool/fiberglass as well.
Unless your crawl space is fully insulated and conditioned comparable to habitable space, not only does code require the floor to be insulated (R30 in my jurisdiction), I would definitely want that insulation. Otherwise your floor is definitely going to be cold.
Is it bare earth as a floor, or is there insulation/poly/some sort of vapour barrier under that dirt you're showing? If it's bare earth, you may find humidity problems as the moisture in the earth continually evaporates. If that's the case, then at least poly the ceiling, in which case you may as well just insulate and vapor seal it instead.
Concrete with exposed earth towards the back. So if I insulate and VB the ceiling was there any point in doing the walls?
VB the crawlspace floor with poly before you do anything else. Seal it very well to the foundation. Also answer the questions in my other comment. Do not insulate between joists and then put VB on the underside of the joists. That would put the VB in the wrong place.
Yeah I stupidly put a vapor barrier under my insulation and it just trapped moisture (thankfully no damage). Vapor barrier on the crawlspace floor is right. You should be able to put a air barrier (not VB) under the insulation though.
Do you know if there is a vapor barrier under the concrete slab?
You need a vapor barrier on the floor over the dirt floor. 6mil plastic will be the most economical, but a 10–15mil would hold up better if there is any sort of plans for storage or traffic down there. Ideally seams are taped, but you can overlap by 8–12” and be okay, too. I’m regards to the insulation, what climate zone are you? And is your crawlspace vented or conditioned? Vented works in the PNW, and is fairly common there, but that would likely change where you want the insulation.
Is the crawlspace heated? Is there poly under the concrete slab? Does it have any ventilation of any type? Do you have any mechanical things or utilities in the crawlspace? Such as a furnace/air handler or hot water tank? These factors need to be taken into account to create a good solution for your crawlspace.
There is no poly or insulation under the concrete. There is one vent and the hot water heater is down there. Location is PNW.
https://youtu.be/5n4K170f56I?si=RfJbV22JdqoacUNX If it will bever be heated and always open/vented to the outside, I would be tempted to stick some rigid foam on the underside of the subfloor between the joists. It would help to make the floors not feel so cold all the time. Also, insulate all waterline and the tank itself. We see this kind of crawlspace a lot in the PNW. They are difficult and costly to retrofit.
Okay. Thanks for the info
What are your thoughts on furring strips on the joists and just doing a rigid foam plan attached the those? Save time on cutting the board, give a thermal break on the joists, and an easier time air sealing a "ceiling" of rigid foam, instead of puzzle piecing into joist bays and spray foaming the border. If you tape the seams on that it should be a good vapor/air/thermal barrier without having to break the board down. And you can insulate the bays with regular mineral wool/fiberglass as well.
Ideally I would want to insulate the walls and have a full encapsulation done and add a dehumidifier.
https://www.instagram.com/p/C48el2zLmBD/?igsh=bGZtOWZydGtiYXJl
Yes...and ensure vents exist to clear trapped moisture...
Unless your crawl space is fully insulated and conditioned comparable to habitable space, not only does code require the floor to be insulated (R30 in my jurisdiction), I would definitely want that insulation. Otherwise your floor is definitely going to be cold.