Cost comparision and CAD model for a Jamaica Cottage Shop 12x40 Home Office shell.

The before tax pre-cut kit cost is $20,018.53 JCS. Building materials are subject to NY state sales tax. In Tompkins County this is 8%. The sales tax would be $1601.48, making the total $21620.01.

The before tax fully assembled cost is $37,618.53 JCS. I am not sure if a prefabricated building would have any tax exemptions so I'll assume worst case normal sales tax of 8%. The sales tax would be $3009.48, making the total $40,628.01.

Post and Beam vs Studs

4x4's used in the post and beam constuction require a saw like a 12" Miter saw to cut with one cut vs a circular saw that would require multiple cuts. 2x4 stud construction could just use a circular saw.

Allowed cut optimizer to choose boards up to 20 ft which was the max length the sawmill offered. May want to constrain to shorter lengths to make material easier to handle. Would likely increase the cost a little.

The Jamaica Cottage Shop cabin is being considered for full-time residential use in upstate NY and therefore must meet applicable building codes.

Sawn lumber utilized for load-supporting purposes must be identified by a grade mark [2020 Residential Code of New York State (RCNYS)], but lumber without a grade mark can be used if sold directly from mill to builder and mill certifies the lumber [TB-1002-RCNYS]. Need to check with local code enforcement and sawmill to be sure.