Can’t tell you how many times I’ve seen people dump cash into insulation and then ignore the basics. On my last build, I spent more time tracking down air leaks than anything else—honestly, a...
I get what you’re saying about air leaks—tracking those down in my 1920s place was like playing whack-a-mole. Still, I’ve gotta say, insulation made a bigger difference for me than I expected. Maybe it’s just these old plaster walls, but after blowing in cellulose, the whole house felt less drafty, even before I got around to caulking every nook and cranny. I do wonder if newer builds just don’t have the same weird gaps as these old houses. And about the mini-split, I’m jealous—my radiators are charming but not exactly “quiet AC.”
You nailed it—old houses are a whole different beast. I had the same experience with my 1940s place: insulation helped, but until I sealed up the attic hatch and some weird spots behind the trim, it was still drafty. For anyone tackling this, I'd say start with weatherstripping doors and windows, then hit the big gaps in the basement or attic before you even think about blowing in insulation. And yeah, mini-splits are a game-changer for comfort... but I kinda love those clunky old radiators too.
Backyard guest house costs are all over the place, honestly. I went down this rabbit hole last year after getting tired of family sleeping on my couch. If you’re thinking about a detached ADU (Accessory Dwelling Unit), you’re probably looking at anywhere from $80k to $200k, depending on how fancy you get and where you live. Permits, utility hookups, foundation work—those add up fast. In my case, just running water and sewer lines from the main house was a headache (and a wallet-ache).
One thing I wish I’d known: don’t get too hung up on the square footage at first. The city’s requirements and setbacks will probably dictate more than your budget does. And if your house is historic or in a designated district, expect extra hoops—my neighbor had to get approval for the siding color and window style to “match the character.” Not cheap.
If you’re handy and up for some DIY, you can save a chunk, but even then, materials alone aren’t what they used to be. I priced out a 400 sq ft cottage with basic finishes and it was still pushing six figures by the time I added up everything—foundation, framing, electrical, plumbing, insulation (which I’m now obsessed with after living in this old draftbox), etc.
One thing that surprised me: prefab units can look tempting, but once you factor in site prep and utilities, the savings aren’t always huge. And if you’ve got an older property, tying into existing systems can get complicated fast. Anyone else run into weird old clay pipes or mystery wiring? I swear my crawlspace is like an archeological dig.
If you’re just looking for a simple studio or office shed (no plumbing), that’s a whole different ballgame—could be under $20k if you keep it basic. But for a true guest house with bathroom and kitchen? Deep pockets required, unfortunately. Still, having a separate space is pretty great... especially when relatives visit and you want to keep your sanity.
City regs and old utilities are the real wildcards, yeah. I’ve done a few backyard builds, and the “hidden” costs always come from stuff like trenching through tree roots or discovering a random concrete slab where you want to put the foundation. If you’re budgeting, I’d break it down like this:
1. Permits and design: $10k–$20k (can be more if you need historic review)
2. Site prep/foundation: $15k–$40k (depends on soil, access, surprises underground)
3. Structure and finishes: $50k–$100k+ (materials have jumped lately)
4. Utilities: $15k–$30k (water, sewer, electric—double if you hit old clay or galvanized lines)
5. Contingency: 10–20% for all the weird stuff that pops up
Prefab can look cheaper on paper, but yeah, by the time you’re done with site work and hookups, it’s not always a huge savings. If you want to keep costs down, focus on simple layouts and basic finishes—custom windows or fancy tile will eat your budget fast.
And yeah...old crawlspaces are always an adventure. Found a horseshoe and a bunch of marbles in mine once.
That bit about “hidden” costs is spot on.
I thought I was being clever by picking the flattest part of my yard for our studio, but ended up paying extra to reroute a sewer line that nobody even knew was there. If you’re creative with finishes—like using reclaimed wood or basic tile—you can save a surprising amount. I actually made a countertop out of old bowling alley wood. Not everyone’s style, but it worked for us and kept things under budget.the “hidden” costs always come from stuff like trenching through tree roots or discovering a random concrete slab where you want to put the foundation.
