Interior walls on earthen floor

We are planning a build this summer and doi ng an earthen floor, but we cannot figure out how to attach the interior walls to the subgrade or basecoat?? We will first be doing a 2" basecoat that has radiant heat at the beginning of construction and then a 1" finish coat towards the end of the build. We are hoping this total of 3" will be sufficient - if anyone has any input or recommendations please let us know! Thanks!

I guess you have rejected the idea of fitting the walls first then laying the floors and heating coils?
Can you install steel brackets prior to laying the floor. Those brackets can be set to the height you need for the floor and wall to meet.
After the floor is finished you can fit the wall to the exposed brackets.

Hi Theresa and welcome to Permies!

First off, I'm assuming by interior wall you mean a wooden stud wall. If so, this wall should not be resting on the dirt but rather elevated by some kind of subfloor.

So then lets talk about what you have planned for your subfloor. Is it going to have insulation and vapour barrier? Will it be a concrete or compacted gravel floor? or be made from beams, joists and plywood?

Yes wooden stud walls, Sorry for the lack of description.  We will first have compacted gravel, then vapor barrier, foam, compacted roadbase, basecoat earthen floor, then the final earthen finish!

Since you are installing your radiant floor first, you obviously know where your interior walls will be so perhaps you could bury deadmen wood strips within the compacted roadbase or as high as the basecoat and use longer screws or bolts to secure the base of your interior walls to them?

I'm liking Gerry's idea - This is essentially placing the sill plate for the wall IN the floor.  It doesn't have to be wood (and if it is wood it must be pressure treated.  or be black locust), but any material that is solid (concrete blocks would also do).  I'd advocate for laying out these boards/blocks and setting a threaded bolt in them - you'll have a floor with a bunch of threaded rod sticking up.  Then you can drill holes in a bottom plate and place on the rod.

The plate can just be held down onto the earthen floor with a washer and nut.  Or, you can get fancy and thread a nut and washer onto the rod, add the bottom plate, and then another washer and nut.  Both approaches will securely anchor the wall... the second method allows you to float the bottom plate above the floor and thus use trim pieces to cover the gap.  Floating the bottom plate allows your floor to move more.

I think we have a much better idea how to make this work! Thank you all so much, it is amazing the support thats on this site. I appreciate the time you take for answering questions and helping others out!

OK Theresa, I'll bite.....what is your idea? Enquiring minds want to know!

Absolutely! We are thinking of doing the anchor bolt idea where we put a 2x4 (pressure treated) into the ground before laying our basecoat. Then when it is time for the interioir walls we will drill through the bottom plate and anchor it down! I will need to burlap of some sort wherever there is wood in the floor because of expanding at different rates may cuse cracking, but i think it should be ok since its the basecoat that 'could' potentially crack? We will also have to be cautious with anchor bolts sticking up on the job site and 3 kiddos though. If you guys have any other ideas or recommendations please feel free to chime in! We have never built a house and its just me and the hubby doing this, so we are open to learning anything and everything!!
Btw, We plan to youtube our whole build process as well so if you ever watch and give tidbits along the way if you see a better way of doing something thatd be wonderful!
Our channel will be called 'building roots'

I've worked with what you are talking about in a cement foundation where the anchor bolts are all around the perimeter and often capped with tennis balls or other protection. Made for a workable situation.  Wondering though that since they are all around on your floor which makes it not only less safe, but a pain to smooth and level around, to go ahead and bury the boards but leave out the bolts and instead come from the top down with securing the bottom sills with lag bolts instead?
Of course you'll have to carefully record where the buried boards are so you don't miss with your bolts!
I think the burlap idea is a good one. Crack prevention is always a good idea.

Look forward to watching your 'roots' grow.