Hi, I build two homes in WA state in a rural area (more on this later) while I was working as a webmaster and all around sysadmin for a small wood distributor co.

First house: 2600sq ft, Full size basement with 2 stories on top of a traditional timber frame structure, wrapped in S.I.Ps (structural insulated panels). We had plans drawn by architects and we went BIG. I ended up acting as the general contractor as the guy we hired ended up screwing up and bailing on us. I did a lot labor along the subs and learned a good deal of many of the trades and what were m,y limitations, what could I do. I also interacted with the building department as a owner-builder, it seems to me that unless you are in a rural area (they helped me and coached me thru a lot), you will have to have some help navigating this aspect too.
Learnings from the first house:
- a project management approach would have saved me time and money.Ask this for your GC, or make sure you look at time-cost-quality on every touchpoint.
- make sure you have contracts with everyone that will be subbing for you. We had a contract with the GC and even then we had to go to court (long side story, headaches)
- Basement concrete walls & foundation were slow to build, expensive and you need to know what you are doing, not something I would recommend for an owner-builder.
- try to design the smallest space you think you need, then cut again on space. If you design with the possibility to expand later on and still be statically pleasing, you will end up ahead on many fronts. We got carried away and built twice as much what we needed with very expensive materials and techniques (timber frame). Cue in 2006-2008 financial crisis. Imagine the rest.

Second house: 1100 sq ft Rastra blocks crawl space Foundation. (Insulated Concrete forms) and S.I.P.s panel walls and roof. I acted as the GC. I subbed the excavation (minimal as I did a crawl space that was barely deep to let me in), and the rough plumbing, as the guy did it in 8 hrs. I did all the finish plumbing. I learned to do the electrical work and wired the whole house, had an electrician friend come connect the main panel to the street tri-phasic high-voltage. SIP panels for the walls of this one story house we raised by hand with my ex-wife. Roof panels we flew in on a single day with 4 friends, had to rend a crane for 6 hrs. With SIP panels you have a closed structure, with all openings framed and ready to be covered in 8 days. Took me 9 months to finish, working evenings and weekends and 1 month summer vacation.

Learnings from second house:
- build small, smallest you need.
- your local hardware store is your training, mentor and partner in this. Most folks are happy to teach you what to use, how to use it. You will end up paying a little more than $BigBox, but you also can ask to get a GC account and discount (around 10-15%). Win-win.
- Labor savings with modular construction techniques such as SIPs and CIFs are huge if you are a DIY builder. Heck here in Sweden even big projects are built modular!

This is a bit stream of consciousness post, apologies as it is late here and also there are so many emotions linked to those two projects... Message me if you need a sounding board to discuss more.

Happy building!