Extreme Enterprise House Cost Detail

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Complete Budget

Future iterations - v3 BOM - [1]


BOM - cabinets - [2]

Catarina - Kitchen BOM





  • Materials for 500sf sanded plywood, stain, varnish floor. - [3]

Prototyping Budget - from Auto BOM Generation

See [4]


  • Sliding saw
  • Cutoff saw
  • Skil saw
  • Cordless drill -
  • Magnesium float with long handle
  • Trowel with long handle
  • Sanded Plywood Floor Tools
  • 4" foam brush [5]


  • Concrete polisher
  • Power float

Cut List Generator for Lumber

Great online resource - [6] Results:

Automated BOM Generator in FreeCAD

See FreeCAD BOM Generator



Foundation Estimate Request Form

See Slab Foundation Estimate Request

BOM Part Analysis

  • Mudsill anchors - [7]. Buy - [8]. But (galvanized) are specifically not compatible with PT lumber. So you would you'd need for PT: [9]
  • Menards version - [10]

Both may work, we know the Simpson do. The load tables are comparable on both Simpson and MiTek



But there are couple things to note:

  • The MiTek one you showed is not for use with treated lumber (which we need since the sill plate must be PT). I don't know if the Simpson one is (they give you a corrosion report, but definitive instructions).
  • One of the things I like about the Simpson connectors is that they already provide the code compliance reports

https://www.strongtie.com/mudsillanchors_concreteconnectorsandanchors/masa-masap_productgroup_wcc/p/masa.masap#CodeReports&Compliance  (so we can just include that on the package to the building department). I don't know if the others have that.


  • 4" SAWP tape - [11]
  • 6" Vycor Pro - [12]
  • 4" Vycor Pro - $26 for 75' - [13]
  • 9" tape is required around windows by code - [14]

12x16 Foot Addition Budget

Roof by Catarina

Spreadsheet - $2183 - [16]


Working Doc - Foundation


Working Doc - Floor, Walls, Roof


Working Doc - Utilities

  • Utility Panel - indoor section
  • Utility Panel - outdoor section
  • PV


Comparison to SIPs

An astute reader will ask - why aren't we using SIPs?

Well, I think it's cost, labor, and customization aspects. Our cost is 1/2-1/4 that of SIPs for a start. Here's the detail as a good study:

  1. Cost - the site says $17-30/sf for shell including roof. For comparison, shell panels (windows not included) in our system are $120 each for a 4'x8' panel -so if we have the most basic square 32x32 feet - cost is $120*32= $3840. But that is finished panels - minus interior exterior finish it is about exactly half of that, $1900. The roof in our case costs $6272 by taking our roof panels into consideration minus the roofing finish. So we are at $8k or $8/sf for comparable shell - as opposed to $17-30 for SIPs.
  2. Labor - small panels are doable by manpower, but not large ones. Our panels weigh between 137 and 211 lb, and 66 lb for roof members. Labor for SIPs is not doable without crane or lift. Our requirement is that 2 people can do the labor themselves without renting any machines.
  3. Customization - distributed supply chain management is harder. Our promise is common, off-the-shelf materials anywhere. I'm imagining that if we have a number of house models - ordering the same thing from many suppliers will be expensive: each supplier would be making custom cuts for only a few houses. I am assuming that this is the reason why no DIY builders use SIPS. Do you know of a single DIY builder, with a custom house, that uses SIPs?