Cost Per Square Foot

Materials

• basic 4x9 module in 2x6 - $6 for a 9' precut. [1]. Framing only is $30/ module.
• Metal Roofing - $1/sf - this is 60 sf - [2]. Up to 36' lengths.
• SIPs - $9/sf for R16. See SIP Panel Cost
• PV Panel Cost - $3.4/sf
• Drywall - $10/sheet, 44 lb [3]. Exterior drywall also exists at $5 more per sheet.
• OSB - 7/16" - $15 [4]. 3/4" - $25 [5]
• Rebar - 35 c/ft [6]
• basic 4x9 module in 2x6 - $6 for a 9' precut. [7]. Framing only is $30/ module.
• Insulation R21 - $0.63/sf [8]. Insulation R11 - 33 c/sf [9]
• Coil is $500/ton from China [10]. If weight is 0.5 lb/sf - then this is $500/4000 sf. Ridiculously low price of 12.5 c/sf
• Hot rolled coil at $1k/ton [11]- 25 cents/sf at the 30 Gauge thickness.
• 2x6x16 roof section, 2' center, can be doubled up. Fastest build model. $11/sf [12]. 16x16 roof section for $121. 320 lb - so must break it into 2 and also thereby make it transportable.
• 45 mil EPDM - $1/sf [13]

About in Housing

Summary: cost per square foot is largely meaningless. You don't know what it means until you consider:

1. Does it include builder's profit?
2. Does it include livable space only? (or other such as garage or porch)
3. Does it include basement?

• To compare house costs properly to the OSE/OBI Seed Eco-Home, we consider new construction (median used homes are $120k lower cost [14])
• Measured for livable space (cost to build the complete home / sf of livable space only) only as the claimed industry standard of measuring cost of a home. Thus, a large garage and porch or upscale interior finish drive the cost up [15]. Does not include land.
• Average USA cost is $150 builder grade [16]. But this figure is different than the industry standard cost method - here they don't include land NOR non-livable space such as garage. Thus, the Forbes definition is not the standard definition.
• Median is more useful with nonsymmetric distributions, such as ones skewed by high cost outliers such as housing. [17]. The average is higher, median is the average Joe price.
• Average sale price of a new home USA is $487K, median is $416k [18]. Or about $190-$220/sf.
• If average cost to build a house is $280k [19], then land + legal is $200k.
• Median sf is 2300
• There are 6 classes of house quality. Lowest cost is $60/sf build cost. Highest is $500/sf (luxury) [20]
• Cob homes are the lowest cost to build, but highest cost to buy [21]. Build cost is way off - it doesn't include any MEP.
• Summary: average cost to build a new home $300k (land not included), to buy $500k [22]. Detailed breakdown of the $500k by NAHB for what appears to be builder grade - [23]
• OSE Value Summary: OSE build cost is $60k materials + $25k labor) for an entry-level, high quality home - $85k or $65/sf for the 1300 sf 3 bed/2 bath model, compared to the $114/sf NAHB survey average (2600 sf). The OSE cost does not include land, site prep, legal, design & engineering, overhead, profit, financing, marketing, sales, or any other fees. The NAHB cost does not include land, site prep, overhead, profit, financing, marketing, sales but does include permit, impact, engineering & design fees.

Examples

• 2023 - $279k, 1700 sf [24]. $164/sf.
• 2023 - $340k, 1500 sf [25]. $227/sf.

Links

• Closing Costs