Bumping out always sounds easier until you hit that first weird pipe or find out the foundation’s not what you thought. When I help folks decide, I usually suggest starting with a detailed floor plan—sometimes you can rework what you’ve got and avoid both shovels and ladders. If you do go up, sealing those new walls is key. I’ve seen people skip air sealing and end up with cold spots everywhere... not fun in January.
Definitely been there with the “surprise” pipes—had a job last year where the bump out turned into a full-on plumbing reroute. Here’s how I usually break it down:
- Bump outs are great if your foundation is solid and utilities aren’t in the way, but there’s always a risk you’ll uncover more work than planned.
- Building up avoids a lot of that underground guesswork, but you’ve gotta make sure the structure can handle the extra load.
- Either way, air sealing’s a must... seen too many folks regret skipping that step when winter hits.
Sometimes just reworking the existing space saves a ton of headaches. Always worth mapping it out first.
Bumping out vs. building up really does come down to what’s hiding behind your walls and under your floors, doesn’t it? I’m right in the middle of planning a small expansion and have spent way too much time reading up on both options. The plumbing reroute thing is exactly what I’m worried about—my house is old enough that every project seems to turn into a scavenger hunt for mystery pipes or wires.
I agree, air sealing is one of those steps you don’t think much about until you’re stuck with drafts all winter. I’ve seen some folks try to save money by skipping it, but then they end up paying more in heating bills, not to mention dealing with condensation issues.
One thing I’d add: when you’re looking at bumping out, it’s easy to underestimate how much exterior work you’ll need. Matching siding or brick, extending the roofline... it adds up fast. And if your lot lines are tight, even a small bump out can trigger zoning headaches. On the other hand, building up means dealing with stairs and possibly reinforcing your foundation anyway, especially if the original structure wasn’t designed for a second story.
I’ve been leaning toward reworking my existing space for now—opened up a wall between two rooms and it made a bigger difference than I expected. Sometimes just moving a door or knocking out a non-load-bearing wall changes the whole flow of the house.
If I do decide to expand later, I’ll probably get an engineer involved early on. The structural stuff gets complicated quick, and I’d rather know what I’m dealing with before anyone starts swinging hammers.
The plumbing reroute thing is exactly what I’m worried about—my house is old enough that every project seems to turn into a scavenger hunt for mystery pipes or wires.
That line made me laugh—been there more times than I care to admit. My place was built in 1912, and every time I open up a wall, it’s like stepping into a time capsule. Last year, I tried to bump out the kitchen by just a few feet, thinking it’d be a straightforward job. Ended up discovering a tangle of knob-and-tube wiring and a cast iron drain line that nobody had mapped out. The electrician actually took photos because he said he’d never seen anything quite like it.
I hear you on the exterior work, too. Matching the old brick was a nightmare. Even after tracking down a salvage yard, the color was just a little off, and now I notice it every time I walk past that corner. It’s one of those things you don’t really budget for, but it makes a difference in how the addition blends in—or doesn’t.
I’ve also wrestled with the idea of building up, but my foundation is fieldstone and not exactly confidence-inspiring. An engineer told me I’d need to underpin the whole thing before even thinking about a second story. That was enough to send me back to the drawing board.
Funny enough, the biggest improvement I made was just opening up a wall between the dining room and parlor. Suddenly the whole downstairs felt bigger and brighter. Sometimes I wonder if we get so caught up in adding square footage that we forget how much you can do by just reworking what’s already there.
Anyway, I’d say trust your gut and don’t underestimate the surprises hiding in old houses. If you do go for an expansion, having an engineer on board early is worth every penny—learned that the hard way.
Bumping out always sounds simpler on paper, but those “little” surprises behind the walls are relentless. I once had a client with a 1920s Tudor who wanted to build up, and we found three different types of insulation stuffed between the rafters—horsehair, newspaper, and what looked suspiciously like old socks. Sometimes just knocking down a wall or reworking a layout makes a bigger impact than another 200 square feet. Plus, you avoid the headache of trying to match 100-year-old brick.
