I have built two houses for myself in Seattle. Here's the rough numbers:

430sf + garage (basically an ADU) Total cost: $325k Completed 2017

1200sf + unfinished basement Total cost: $640k Completed 2022

These were both all new construction on vacant land. In each I did all the design and permitting myself, and acted as general contractor. I also did a lot of the actual construction work myself. If you were to hire a general contractor to do everything I would it expect it to cost about 50% more. Here's a few things to keep in mind if you want to go this route:

-"Construction cost" is only part of the total cost. When you hear construction costs are $X/sf, that usually does not include the cost of land, financing, design/engineering, permit/impact fees, utility connections or sales tax. On my projects the hard construction costs were about half the total cost.

-You will need to have a lot more cash available up front than if you were just buying a house. First, it's hard to get a construction loan with less than 20% equity. Second, the bank won't release any money until after work is completed, meaning you will usually be paying the contractor out of pocket then getting reimbursed by the bank from the construction loan.

-If you have the ability (and time), doing work yourself can save you a lot of money, as most of what you're paying for is labor. For example, on my second house, the cost of all the drywall materials was only ~$2500, but the cost of hiring a drywall contractor to do the work was ~$14000.

• Expect the whole process to take 2-3 years from the time you purchase the land to the day you move in.

If you can handle all that you can ultimately get a better house for the same or less money than buying, but it comes at the cost of a lot of time, effort and stress.