Straw Bale Building Resources

Straw Bale Material Calculator

New! Straw Bale Material Calculator


This Calculator Tool is highly specific to estimating key materials for building wall systems using straw bales. It has been created for owner-builders and contractors with a good to excellent knowledge of straw bale construction.

What it Does

  • Makes calculations easy for pertinent material quantities for bale walls
  • Provides output for simple ordering/pricing of bales, plasters, paints, mesh and binding materials
  • Provides output for simple ordering/pricing of Harvest Homes products: Mesh, Hemp Hurd (binding material) and Silicate Paint.

What You Need to Start

  • Rough dimensions of house footprint/plan


  • We assume you have a good to excellent knowledge of straw bale construction and are familiar with terminology, such as edge stacking. If you don’t have knowledge of straw bale construction, it won’t be easy to understand the inputs or interpret the outputs. We recommend some significant research (books, videos, workshops).
  • The calculator assumes that you will use the Harvest Homes construction methods for building with straw bales (walls, curbs and top-plates). This said, the output of the calculations is transferable and scalable (with some interpretation), to other styles of straw bale construction.

Claim of Accuracy

  • Totals are accurate if you construct walls according to the Harvest Homes construction methods. The material calculator provides for some margin of error, calculating the surface/area regardless of number and size of openings.
  • Totals are based on a two-string bale with an average length of 36 inches.

Wall Charactertistics

Cement Lime Plaster assumes that your cement content is not more than 50% and lime not less than 50% sand as the aggregate. We always use Saint Lawrence Cement Mason’s High Bond Portland-Lime Type N. You can source equivalent product in your area.

Earthen Plaster assumes a plaster of approximate proportions, 25% clay, 25% sand, 25% manure or sillage and 25% chopped straw. For precise recipes, we recommend thorough research and understanding of earthen plasters, site conditions, available clay and other conditions that affect recipes.

  Height Width Length
Edge Stack: 18” 14” 36”
Regular Flat Stack: 14” 18” 36”

While edge stack provides savings in the number of bales and works well for cement-lime plasters, this orientation of the bale should not be used if you are planning to use an earthen plaster.

Exterior Wall Dimensions (All measurements are in feet)

Gable Length:
Roof Pitch:

Gable length is the distance of the bale wall from corner to corner at the base of the gable. This automatically assumes a matching, opposite gable wall and multiplies your length by two. For designs without matching gable walls at each end, some interpretation will be necessary.

Roof Pitch:
12/12 pitch
(45 degrees)
3/12 pitch
(25 degrees)
0/12 pitch
First Storey North East South West
Wall Length:
Wall Height:

Exterior Openings (All measurements are in feet)

We assume in these calculations that the openings are rectangular, all sides are 90 degrees to the window, using plywood to form the opening (window/door buck). If you select round, it assumes that all sides are curved to some desired radius, using diamond lathe to form the curves.

Windows Qty Type Height Width
Doors Qty Height Width

Note: The material calculator provides for some margin of error, calculating the surface/area regardless of number and size of openings.