Its the same weight so if your foundation can't handle it it will require repair. Shed dormers are probably cheaper to build since the structure is simpler. Not cheap though... We added a dormer to our four story townhouse and had to extend structural framing all the way down to the slab tearing open spaces that otherwise were out of scope

Not enough information. Are the footings not wide or thick enough? Is there a basement or only a thickened slab edge. Is there a soil issue? What is the climate? What is the height of the ridge form the second floor? What is the roof slope and framing? Are there any bearing walls near the ridge?

Does the problem apply to perimeter footings or interior footings or both? Are there foundation piers or stem walls?

Also, we don't know how the engineer framed the dormer they designed. Why so sitngy with information?

I can tell you that all loads must reach the foundations so the configuration of the dormer might spread those loads differently but the total loading won't change.

However, in general, a shed dormer might maintain the original uniformly distributed load on the exterior wall and foundation thereby not changing the loads on the foundaiton. I suspect the engineer's gable design created 2 point loads on the front wall (but without the engineer's drawing I'm only guessing). There are many ways to frame any style of dormer.

I don't know enough about the ridge, the roof slope or interior bearing walls and footings to say how that load could be supported.

There is no straightforward answer, other than hire a local architect that is trained in architectural design and structural design.

Here's my best stab at a thorough answer to the above...

The house is 45 years old. The room I'd like to dorm has a floor made of 2x9" joists 12" OC. The front and rear walls of said room are supported by 4x4 posts on 10" interior piers spaced 4' in our crawlspace. We're in the SF Bay Area.

The reason I keep coming back to Houzz with these questions is that (at least on other topics) I've gotten some great advice. I have worked with a series of Architects and Engineers, and frankly find them all to be overpriced and difficult to work with -- none want to do site visits any longer since COVID, so they've got me cutting into drywall and crawling under the house to tell them how it's built, then won't answer questions about alt design approaches. I don't have $500,000 to build a dormer, which is what my gabled design is being bid out at. So I'm trying to find some information on alt approaches that might "typically" have lower building costs because the architect and engineers I've paid over $15k to already won't attempt to answer that question for me.

@Nezumi Dezainā the house is 45 years old. So probably not to current codes. Here in CA our engineers over design everything because of the potential for earthquakes.

@res2architect stingy on information because I'm not an engineer and didn't think it appropriate to try to lay down the entirety of my house's design in this forum. Typically the answers don't go too technical.

@Patricia Colwell Consulting please stop replying to my posts.

@Big Dig Construction The room was finished and furnished when we moved in, but yes, it's possible it was built out after the original home. We've requested records from our county but they don't have copies. And yes, I've posted a couple of times before for this project. Getting bids for $500k so I'm trying to really understand the requirements of this project and what it entails. Your response is dismissive and incorrect. I've NOT yet asked which type of dormer style typically has less structural reinforcement requirements, which was the point of this post. Previously I had asked about aesthetic guidance. That got me to where I am today, with a $500k proposal.

@Mark Bischak, Architect see my initial reply. You've replied to my previous posts as well and suggested as much. I took that advice I'm $15k in the hole with an unaffordable (for myself at least) plan. We've renovated multiple homes over the years -- first time working with architects and engineers. We've worked with at least 3 architects, 2 engineers now. All do the exact same thing... charge us to send out someone to measure our house, because "they don't trust the last ones' measurements", listen to us and our budget goal, and come back with plans that are typically 4-5x our budget. Then they shrug and are done with the project. Nobody ever says "you can't build a dormer in that style for anywhere near the budget you have" before taking the job.

Perhaps a dormer is not your solution. I would like to think there exists a local architect that can identify your needs (not solution) and come up with a solution that meets your needs and is within the existing constraints, including budget, for a reasonable cost. Unfortunately it seems that has not occurred. Normally the architectural design process goes through three phases: schematic design, design development, and construction documents. There should be a cost estimate done at least at the end of each of the phases.

Thanks, Mark — that hasn’t been my experience but it makes sense. In lieu of that guidance ive kept coming back here to houzz. ill continue to search.

Thats $2,000 sq/ft… that’s not a normal price for our area.

i listen just fine — what you see as stubborn i see as frustration. im not married to any design or approach. we have a budget and nobody we’ve worked with has taken that seriously.

you cant block or mute people on this platform, to my knowledge, so why cant i ask patricia to stop? i find her responses to sound critical rather than helpful, and shes commented on almost all of my posts here over the years. why cant i push back?

@Big Dig Construction i appreciate that explanation — sounds like the seismic work is just something we’d have to factor in then. maybe the simplest answer is we cant achieve our goal within our budget

It was sold describing the room as den/”office space”. it was carpeted, with a light switch, outlets, no windows.