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Background: structural engineer, have worked with prefab construction in various capacities The short answer to this question is "because we haven't figured ou

Background: structural engineer, have worked with prefab construction in various capacities The short answer to this question is "because we haven't figured out how to make it less expensive than regular site built construction". The longer answer: prefab, or modular, construction has made inroads in various construction niches. Parking garages are nearly all prefabricated concrete for instance. Light framed buildings (either wood or cold formed steel) frequently have their structure panelized off site. Hotels (especially in places where the cold weather means a short construction season) are sometimes built using prefab modules. It's also super common to have prefabricated lower-level components - wood trusses, bar joists, hollowcore panels, etc. But any higher degree of prefabrication tends to be more expensive than conventional, not less. They mostly get used when their perceived benefits outweigh their costs. (If you look at a panelizer like Entekra's benefits page, they don't list "cheaper" anywhere). Two major exceptions to this are parking garages and HUD homes, which (among other reasons) are heavily optimized for a particular form factor. Regarding Bone Structure, it's an interesting system, and I love seeing people tackle this problem space. But I rate the chances of a custom fabricated steel structure ever being less expensive than conventional wood framing as "very near zero". This seems limited to the high end custom home market, and their marketing material seems to indicate that as well.

jaclaz 6y ago
Only to somehow confirm anecdotally what you said but in another area of constructions. I have been working in and around the construction industry for the last 35+ years in Italy and in the '90's the firm I was working for had a department for pre-fabricated (concrete) buildings (more like condos or office buildings than "single" homes), which was led by an engineer that was - really - a technical genius and - besides him - we did have exceptionally good staff, both the technicians and the workers. In the arc of more than ten years we tried everything and the contrary of it and after several , generally successful or mostly successful, built projects (with only a few minor issues in a few of them) we came to these conclusions: 1)you can make cheaper pre-fabricated buildings only if the level of finiture and overall result is cheaper or feels cheaper or looks cheaper 2) you can make pre-fabricated buildings that are as beautiful, functional and what not as "built-on-site" but that will cost the same (or more) as the corresponding built-on-site ones 3) the one and only difference was time, with pre-fab buildings we could build in 6-8 months time buildings that would have otherwise taken 18 months or more (this worked very well for rebuilding after an earthquake) In the years since I was involved in several more similar to the US timber based projects for single homes or anyway one/two storeys structures, and "components" (like pre-fabricated bathrooms "cells" for industrial buildings and hotels) and my experience did not change the overall opinion much. For anything that is "modular" or very, very "standard" (i.e. homes from catalog) there may be some space for fair competition (slightly lower cost for same or similar "quality" of end results), but when you start to include in it: 1) the local building codes (and possible needed deviations from the "standard") 2) the customers' changes/preferences 3) the architects/designers (with all due respect for the category) "whims" It invariably ends up costing the same or more (money) and almost the same (time).
- briancp 6y ago
  This is super interesting, I'd love to hear more about the systems you were using if you're up for discussing. briancpotter@gmail.com

jaclaz 6y ago

Only to somehow confirm anecdotally what you said but in another area of constructions. I have been working in and around the construction industry for the last 35+ years in Italy and in the '90's the firm I was working for had a department for pre-fabricated (concrete) buildings (more like condos or office buildings than "single" homes), which was led by an engineer that was - really - a technical genius and - besides him - we did have exceptionally good staff, both the technicians and the workers. In the arc of more than ten years we tried everything and the contrary of it and after several , generally successful or mostly successful, built projects (with only a few minor issues in a few of them) we came to these conclusions: 1)you can make cheaper pre-fabricated buildings only if the level of finiture and overall result is cheaper or feels cheaper or looks cheaper 2) you can make pre-fabricated buildings that are as beautiful, functional and what not as "built-on-site" but that will cost the same (or more) as the corresponding built-on-site ones 3) the one and only difference was time, with pre-fab buildings we could build in 6-8 months time buildings that would have otherwise taken 18 months or more (this worked very well for rebuilding after an earthquake) In the years since I was involved in several more similar to the US timber based projects for single homes or anyway one/two storeys structures, and "components" (like pre-fabricated bathrooms "cells" for industrial buildings and hotels) and my experience did not change the overall opinion much. For anything that is "modular" or very, very "standard" (i.e. homes from catalog) there may be some space for fair competition (slightly lower cost for same or similar "quality" of end results), but when you start to include in it: 1) the local building codes (and possible needed deviations from the "standard") 2) the customers' changes/preferences 3) the architects/designers (with all due respect for the category) "whims" It invariably ends up costing the same or more (money) and almost the same (time).

briancp 6y ago
This is super interesting, I'd love to hear more about the systems you were using if you're up for discussing. briancpotter@gmail.com