What do I need to know before doing a live-in flip?

[Kelly Cohane]

There is a single family home built in 1935 that is for sale by owner. We want to seller finance the deal. The house is a single story 1,532 sqft with 3 beds and 1 full bath. The lot size is 7,840. We would like to build an addition to increase the livable space to 2,000-2,200 sqft and at least 3 bed 2.5 bath. We plan to make this our primary residence and live in the house while we flip it. What do we need to know before taking on this type of project? Any tips on seller financing would also be helpful. Thanks!