Masters start life at 100K in Podunk. Add 50% for your location. And that’s for a low end product. Double that if you want something without plastic and carpet. Triple it if you want to start getting in to upper end choices.

@GreenDesigns Thanks for your reply.

We are not looking for something fancy with high end materials but for something functional and someone who could design and execute the projet providing good tips to optimize our new space.

We already have the bedroom, the extension would be to add a bathroom with:

- double sink vanity

- 1 shower

- 1 toilet

- a big closet or walk-in closet

We were more thinking around 50K - 70K.

Would that be doable?

Anyone else built this type of extension / addition in SF bay area?

Thanks,

Aline & Dorian

(also, they already had the slab for their screened porch; they only added about 20 sq ft of foundation to it).

@NYCish Ok, sounds good, thank you so much for sharing your parents' experience, it helps to get the idea of the cost estimation, altough we know it will be much more expensive in our area! Thanks again

Maybe if you post your floorplan, houzzers could help you see if a bath could be carved out from existing space instead of doing an extension?

I get it...it seems like an insane amount of money for adding such a small room. Everyone on HGTV just says “oh we can bump that room out no problem” but the costs are never fully broken down or explained.

For typical general remodel projects in this area, you are looking at $300 and up per square foot. But that doesn't work for things like bathrooms.

Bathrooms and kitchens are by far the most expensive remodeling you can do. It pulls in every trade. You have to do framing, plumbing, electrical, tiling, insulation, sheet rock, painting, ... And it has all of these things in a relatively tiny space. That drives the per-square-foot cost up a lot.

Now, if you want to do this as an extension, you can add foundation, siding, roofing, windows, ... to your list of things that you need to pay for.

At that point, you also need an architect, and you might have to go through a more elaborate planning process with the city.

You pretty much picked the most difficult project that you could. And yes, at this point, it doesn't really make a difference whether you add 100 sqft or whether you add 200 sqft. It'll cost you virtually the same. Material costs are really the least of your concerns.

Start interviewing general contractors. This is going to take time and money. And you really don't want to cut corners. When you are done spending all this money, you want to make sure its done right and doesn't have to be redone, because you found out that your foundation wasn't poured correctly, or the shower pan wasn't water proofed.

On the other hand, if you don't care about workmanship, then I can probably find some shadier guys that do all of this without needing subcontractors nor permits, and they bang it out in a month or two. I think my in-laws probably still have the contact information for the guy that butchered their space.