Which is Cheaper: 30 Separate Houses or a 30-Story Building?

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Discussion Overview

The discussion centers around the comparative construction costs of 30 separate houses at ground level versus a 30-story building, with considerations for different quantities of houses (10 or 20) and the potential linearity of construction costs. Participants explore various factors influencing these costs, including structural requirements and logistical considerations.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Exploratory

Main Points Raised

  • Some participants question whether the construction costs scale linearly with the number of houses, suggesting that costs may not be straightforwardly proportional.
  • Concerns are raised about additional costs associated with structural support for lower levels in a tall building, which may need to be reinforced to support the weight of higher levels.
  • Participants discuss the implications of water pressure and the costs associated with pumping water to upper floors, noting that water tanks are often used to maintain pressure rather than solely for supply.
  • Some argue that while a tall building requires elevators, separate houses necessitate roads or walkways, which could influence overall costs significantly.
  • One participant suggests that the construction of a tall building involves higher incremental costs per additional story due to structural and safety considerations, including wind loads and foundation requirements.
  • Another participant mentions that the construction of separate houses may allow for common walls, potentially reducing costs compared to standalone structures.
  • Some participants express skepticism about the feasibility of stacking houses, questioning the structural integrity and practicality of such an approach.
  • There is a mention of the complexity of factors involved in this comparison, indicating that the question may not have a straightforward answer.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the comparative costs, with multiple competing views and uncertainties remaining regarding the factors that influence construction costs for both separate houses and tall buildings.

Contextual Notes

Participants highlight various assumptions and conditions that may affect the discussion, such as local building codes, materials used, and geographical factors like seismic activity, which are not fully resolved.

Frenemy90210
What is cheaper,
the construction cost of 30 separate houses at ground level vs
that of a 30 storied building, with one house per floor and exactly same layout ?

Also, how about 10 or 20 instead of 30 ? Does it linearly scale ?
 
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Frenemy90210 said:
What is cheaper,
the construction cost of 30 separate houses at ground level vs
that of a 30 storied building, with one house per floor and exactly same layout ?

Also, how about 10 or 20 instead of 30 ? Does it linearly scale ?
Have you any thoughts on the linearity of construction costs?
 
Frenemy90210 said:
What is cheaper,
the construction cost of 30 separate houses at ground level vs
that of a 30 storied building, with one house per floor and exactly same layout ?
Bystander said:
Have you any thoughts on the linearity of construction costs?
I suspect, costs may linear. But, I am not from construction field. So I am purely guessing.
 
Frenemy90210 said:
purely guessing.
F'rinstance: water pressure?
 
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Does the cost of the real estate factor into this?
 
sandy stone said:
Does the cost of the real estate factor into this?

Nope. Just the construction costs.
 
Bystander said:
F'rinstance: water pressure?

Ok, I guess you are saying water pumping expenses will add up.; Then also, may be elevator costs.
 
Think of it this way. Suppose you live in a neighborhood where every single house is identical. Tear the roof off of every house except one. Start stacking houses up one on top of the other saving the house with a roof for last. Other than the obvious of only the first story house having a front door that is actually useable, don't you think this would have failed long before the stack got very tall? Modern houses are designed and built to hold their own roof up with not a lot more to spare. However, you would be saving 29 basements or foundations.
 
I think there would be some additional cost arising due to the lower levels needing to be strengthened so they can safely support higher levels.
 
  • #10
Frenemy90210 said:
Ok, I guess you are saying water pumping expenses will add up.; Then also, may be elevator costs.
Yes, and steel. A 20 floor building is more than just two 10 story buildings on top of each other.
 
  • #11
Averagesupernova said:
Think of it this way. Suppose you live in a neighborhood where every single house is identical. Tear the roof off of every house except one. Start stacking houses up one on top of the other saving the house with a roof for last. Other than the obvious of only the first story house having a front door that is actually useable, don't you think this would have failed long before the stack got very tall? Modern houses are designed and built to hold their own roof up with not a lot more to spare. However, you would be saving 29 basements or foundations.
This article suggests that 29 stories using wood framed construction would indeed be rather optimistic.
 
  • #12
A tall building requires an elevator, but separate houses need roads - at least walkways - to link them. How far apart they are will influence the cost a lot. Even as "separate" houses, the buildings may have common walls, reducing construction & maintenance costs.
 
  • #13
Frenemy90210 said:
What is cheaper,
the construction cost of 30 separate houses at ground level vs
that of a 30 storied building, with one house per floor and exactly same layout ?
What is the point of asking this? The number of factors involved is very large and the intangibles are also considerable, so what is it exactly that you are trying to figure out?
 
  • #14
Speaking VERY GENERALLY:

The taller you build a building, the higher the incremental costs per story. In fact, after a certain point (obviously depending on the materials, style, function, etc) the cost to add additional floors gets very very high. There are numerous reasons for this -structural, infrastructural, maintenance, stability and construction of load bearing foundation, load bearing walls and internal structure, effects of wind, general other safety issues, proximate construction costs and tons of others. There also comes a point after which you can throw as much money as you want at the project but could not reasonably build it any taller.

Notably, the energy needed to pump water to the upper floors isn't as big of a deal as one might think. That is why there are water tanks on the roofs of tall buildings... not to provide a supply of water, but to maintain pressure. That way it is more just a matter of moving the water rather than having to do all the usual work one would associate with lifting it.

This is all from memory, but I am sure that some basic texts on architecture, urban planning and the like all go into this in abundant detail.

--diogenesNY
 
Last edited:
  • #15
After watching a 'social housing' development grow beside my local supermarket, there's more to consider.

A 'tower' block is built one floor at a time, and its frame must support all of them, plus wind-loads, plus cladding that will endure such wind-loads. Are you in a 'seismic' zone ??

The development was built in parallel, with several properties at similar stages at any time. Being low, only 2~3 floors, construction was lighter, access easier. And, they are 'walk-up', so no elevators or complex fire suppression / containment required.

Given 'Western' housing towers are rarely 'elbow to elbow' as in many Asian cities, there's not much saving in 'footprint'...

Getting the pro/con balance right is non-trivial.
 
  • #16
@Nik_2213, perhaps you didn't notice it but the OP is no longer with us.
 
  • #17
Sorry, I'm tired, and the strike-through is easy to over-look at my three 1600*900 displays' resolution.
Will try harder...
 

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