site banner
PaperclipPerfector  18hr ago (text post)   656 thread views

Friday Fun Thread for October 10, 2025

Be advised: this thread is not for serious in-depth discussion of weighty topics (we have a link for that), this thread is not for anything Culture War related. This thread is for Fun. You got jokes? Share 'em. You got silly questions? Ask 'em.

Top Bottom Old Controversial Comments
Jump in the discussion.

No email address required.

Let's say I want to build a house for seven occupants.

I guess your calculations are just for fun? What kind of living situation are you envisioning where such high density is required, but you are able to get what look like relatively modest building costs?

In an modest sized city or inner suburb of a larger city 2-1/2 level town homes or even 5-over-1 stumpies seems like the more common solution to medium density moderate cost housing. In exurbs or rural areas pre-fab is more typical of small home lower cost housing. To make new construction marketable, you would be talking about like factors of 2-3x on square footage for anything that would actually sell to a seven person household market.

The HVAC costs also look suspect for meeting current ASHRAE guidelines for 7 occupants. To have decent air quality for seven people in a house that small you are talking about 4-5x the total HVAC cost you have estimated here. Probably a dedicated enthalpy recovery ventilator, dehumidifier, and roughly 2x sized HVAC unit than would normally be used for a 1200 ft2 house. You also would need to scale up other mechanicals if you are going to house seven, like electrical service, hot water heater, sound isolation, etc. Square footage also need to be allocated for mechanicals if you assume you are occupying the basement and/or attic. If ducting and plumbing is going to be run between floors, you also need to a assume extra cost for engineered open web flooring trusses. That or oversized basement walls so you can drop the ceiling, again additional cost over the per ft2 pricing for typical construction used here.

Is the idea two parents and five kids? A decent number of municipalities wouldn't even allow seven non-related people to occupy a single family residence. I know people do it, but asking three kids to share a 10x10 room is a lot by modern American standards. There aren't that many people who want to actually live out Little House on the Prairie anymore. More power to you if you're serious about raising five kids, that's truely excptional in this era.

Even people who are into smaller houses for efficiency/environmental reason like the "pretty good house" people are talking about:

Be as small as possible: 1000-1500-1750-1875 ft2 for 1, 2, 3, and 4+ inhabitants

You're talking about 1182 ft2 for 7 inhabitants!

Does it really make sense that putting the bedroom floor halfway below ground is significantly more expensive than putting it all the way below ground?

For your two-story finished basement example, probably a reverse living layout makes sense. Don't forget each bedroom would then require an escape well then though, which will substantially increase basement construction costs. That's a lot of extra form and mason work. I wouldn't be surprised by a $30k delta on cost even without the escape wells. For basements you have the extra concrete yardage of the basement walls including structural considerations for the extra back-fill pressure, extra excavation and haul away work, workers now have to set up ladders or scaffolding to get into the hole, extra below ground rated waterproofing, extra below ground rated insulation, extra water mitigation measures (you're closer to the water table), extra radon mitigation measures (you're closer to bedrock), etc, etc. Like the size of excavator the contractor will have to use is easily 2x the cost of ownership to the contractor.

Edit: I see you're estimate was that a finished basement is cheaper than the split level. This is entirely down to your assumption that you can halve the footprint square-footage. Practically speaking, if you are going to use a basement for bedrooms you should assume only 1/2 of the building footprint is usable in the basement for that kind of purpose. You're going to need redundant sump-pump wells if you are going to be putting finished bedroom space down there to start. The costs also obviously don't just scale, but have at least a constant component. Like if a contractor is going to haul a medium sized excavator out to a job site you're going to pay for at least a whole day regardless of the square-footage of the hole they are digging.

I guess your calculations are just for fun?

Yes. (I've already hired a contractor to build a house, nominally for five occupants but actually for only two.)

What kind of living situation are you envisioning where such high density is required, but you are able to get what look like relatively modest building costs?

I don't see why a person can't build a small house in a cheap area. It's what I'm doing.

The HVAC costs also look suspect for meeting current ASHRAE guidelines for 7 occupants.

More specifically: In the per-assembly section, the book says that, for a 1200-ft2 house in year 2019, a cooling system costs 5.8 k$, while a heating/cooling system costs 11.6 k$. The number given is per ft2, not per occupant.

Square footage also need to be allocated for mechanicals if you assume you are occupying the basement and/or attic.

If you look at the designs, I have provided a laundry/utility room for the furnace (in addition to the washer, dryer, and circuit-breaker box).

Is the idea two parents and five kids? A decent number of municipalities wouldn't even allow seven non-related people to occupy a single-family residence. I know people do it, but asking three kids to share a 10′×10′ room is a lot by modern American standards.

These designs are compliant with the 2024 International Property Maintenance Code, which prescribes minimum bedroom area of 70 ft2 for one occupant or 50 ft2 per occupant for multiple occupants. They exceed the IPMC's requirements for dining/living-room area.

I do think sketching floor plans is quite fun.

Where did you end up for final square footage? Closer to 1050 ft2 based on removing 120+ a bit ft2 from your smallest seven person design, closer to 1200 ft2 like your seven person design / scaled larger design, 1500 ft2 like the PGH 2 persion target, or 1875 like the PGH 4+ person target, even smaller since it's actually for only two?

I'm very much in favor of building the design of house you want with the best quality materials you can afford, even at the tradeoff of square footage. Provided, that is, resale does not have to be a consideration. Unfortunately, square footage is the most dominant factor in sale price. For most of the housing market , price and price/ft2 seem to be the dominant considerations.

If you've actually signed for a custom built, you probably know better than me, but I always though custom would be a 20-30% premium over a spec-built house, which would be a 10-20% premium over a tract house, which would be a 20-30% premium over a prefab. I'd be interested to know what the final premium is over just dropping a same bed/bath cheap trailer on your lot ends up being. I would rather live in a small custom than a trailer, but I assume most people living in small homes in cheap areas are doing it because it's cheap, rather than aesthetic preference.

I did see the utility rooms in your plans. It's pretty generous for a washer drier, but I imagine pretty tight if you also need to fit an air handler, return, ERV, and 80 gallon hot water heater. You could make everyone take cold showers or pay the premium for an instantaneous hot water heather though I guess.

The square footage based HVAC calculation probably assumes average bedrooms/people per square foot. If you are following IRC you would at least need it to be based off of bedrooms. I'm pretty sure that table is based off of ASHRAE 62.2 though, and they just assumed 2 people in the master and 1 in each other bedrooms. I think ASHRAE probably prefers HVAC techs to use their (person + ft2) calculation if you actually intend to occupy at very high densities. I don't particularly mind a small space, but small and stuffy sounds very unpleasant.

Where did you end up for final square footage?

If you're referring to the design that I'm actually having built, I went with the third drawing in this image.

  • 744 ft2: Most efficient, but has the kitchen in an L-shaped position that IMO is awkward in juxtaposition with the highly linear dining/living room

  • 793 ft2: Less efficient, but looks better; unfortunately can't fit into my lot's 35-foot-wide buildable area without rotation

  • 873 ft2: Final choice; originally drawn by the contractor's drafter, redrawn by me here

  • 857 ft2: A less ugly design, centered on a corridor rather than on a dining/living room, presented for comparison purposes

I always thought custom would be a 20–30-% premium over a spec-built house, which would be a 10–20-% premium over a tract house, which would be a 20–30-% premium over a prefab.

RSMeans says similar things. For a 1000-ft2 one-story house, the 2019 numbers are:

  • Economy: 124.3 $/ft2

  • Average: 144.55 $/ft2 (+16 % vs. economy)

  • Custom: 198.65 $/ft2 (+37 % vs. average, +60 % vs. economy)

  • Luxury: 233.9 $/ft2 (+17 % vs. custom, +88 % vs. economy)

I signed a contract to build my 873-ft2 design for 221 k$ (253 $/ft2) including driveway and fence. Due to a miscommunication, the contractor also offered a price of 193 k$ (221 $/ft2) not including driveway and fence. This probably is a waste of money in comparison to just buying a manufactured house (or perhaps obtaining a modular implementation of the 857-ft2 design), but I wanted to splurge on implementing my own design, since I'll be living in it for 50 years.

I did see the utility rooms in your plans. It's pretty generous for a washer/dryer, but I imagine pretty tight if you also need to fit an air handler, return, ERV, and 80-gallon hot-water heater.

Possibly, but I assumed the use of forced air in these designs just for simplicity, to align with the book's default assumptions. If I were actually having these houses built, I would use ductless heat-pump HVAC rather than forced air, freeing up a lot of space.

I don't particularly mind a small space, but small and stuffy sounds very unpleasant.

Not mentioned in the book's per-square-foot numbers is default window area. I generally would put 4-foot-wide windows everywhere (2 feet tall in bathrooms, 3 feet tall in kitchen, 4 feet tall elsewhere), which would more than suffice for the IPMC's light/ventilation requirements.

I had an apartment with almost the same layout as your build. Very functional and reasonably comfortable for two. Of course we only had windows on one side, unlike your build. We did host another couple for a total of four for a while, and it was fine. Probably could have squeezed another person in if needed. I wouldn't want to live that way long term, but seems very reasonable for two for now, hosting up to five.

Given current construction prices and the size of your build, you either got a great deal or live in the middle of nowhere or both. If you really are staying for a while, I think the splurge is worth it. We can't all build a Monticello, but there's something to be said for living in a house of your own design.

Opening a window is a good option for ventilation as long as the weather is good and there's not too much outdoor pollution. Unfortunately the number of places that have good weather most of the year, don't have wildfire smoke or car exhaust outside, and are affordable is pretty small. For a house that small though, you probably are fine with just exhaust fans and some makeup air to a small air handler. The extra energy cost over an ERV/HRV is probably pretty small given the small square footage.

Given current construction prices and the size of your build, you either got a great deal or live in the middle of nowhere or both.

The 2019 RSMeans book indicates that the cost multiplier of my new house's location is 0.92. (Some states have locations as low as 0.74.)

For a house that small, you probably are fine with just exhaust fans and some makeup air to a small air handler.

It's an interesting idea. I see that, according to the Architectural Graphic Standards for Residential Design: "Most new residences are too tightly constructed to provide adequate leakage ventilation. Therefore, manual and mechanical ventilation are recommended."

What is this place?

This website is a place for people who want to move past shady thinking and test their ideas in a court of people who don't all share the same biases. Our goal is to optimize for light, not heat; this is a group effort, and all commentators are asked to do their part.

The weekly Culture War threads host the most controversial topics and are the most visible aspect of The Motte. However, many other topics are appropriate here. We encourage people to post anything related to science, politics, or philosophy; if in doubt, post!

Check out The Vault for an archive of old quality posts. You are encouraged to crosspost these elsewhere.


Why are you called The Motte?

A motte is a stone keep on a raised earthwork common in early medieval fortifications. More pertinently, it's an element in a rhetorical move called a "Motte-and-Bailey", originally identified by philosopher Nicholas Shackel. It describes the tendency in discourse for people to move from a controversial but high value claim to a defensible but less exciting one upon any resistance to the former. He likens this to the medieval fortification, where a desirable land (the bailey) is abandoned when in danger for the more easily defended motte. In Shackel's words, "The Motte represents the defensible but undesired propositions to which one retreats when hard pressed."

On The Motte, always attempt to remain inside your defensible territory, even if you are not being pressed.


New post guidelines

If you're posting something that isn't related to the culture war, we encourage you to post a thread for it. A submission statement is highly appreciated, but isn't necessary for text posts or links to largely-text posts such as blogs or news articles; if we're unsure of the value of your post, we might remove it until you add a submission statement. A submission statement is required for non-text sources (videos, podcasts, images).

Culture war posts go in the culture war thread; all links must either include a submission statement or significant commentary. Bare links without those will be removed.

If in doubt, please post it!


Rules


Recommended Posts And Communities

Recommended Realtime Chats