Talk to a local builder to get a rough generic estimate. If the estimate is acceptable, hire a local architect to design an addition that meets your needs and fits the site with the estimate in mind. If the builder that gave you the estimate is the builder you want to build the addition, have them involved in the design process to help keep costs in line.

@Mark Bischak, Architect Thank you for advice! Appreciate!

Thank you @res2architect Attaching photo of area - off bedroom and basement. Roughly 20’ of patio in each direction. House is 25 yrs, one thought is we’d not recover cost if we add on and someday sell - but we would enjoy our home for hopefully years. The house needs new windows, paint on exterior. We like our location a lot. Thank you.

It would be faitly easy to extend out the main gable of the home in that direction. Easy only translates into a slight bit cheaper than expensive, as you would be digging into that slope and need to regrade the lot to fix the drainage issues. The wing walls are really odd. Any plan should seek to address thrm. As in remove them. Or is this a duplex, aand those are in place to provide privacy?

The wing walls appear to be retaining walls that allow the lower level to be at grade.

@res2architect Yes you are right about the walls. Walk out basement.

Hu-380369063, Did you finish your project? I’m dealing with a very similar issue. Love the location of my duplex, but need more square footage. Current home is a 832 square feet “treehouse”.