Cost Analysis of Straw Architecture

Fifer Pig
Old Sow’s Sty, McDonald Farm
Storyland, USA

Dear Sir:

As per your request, I have prepared the following cost-benefits analysis on the desirability of constructing your future home of straw.

The excellent availability and low cost of this material makes it practically a steal as a construction medium.  The 8-feet tall walls for rectangular, modest 144 square feet home (15X15 exterior, 12X12 interior) requires about 126  bales and can be erected by the homeowner and a few friends within a day.  However for this design, an additional cost would be the construction of a roof requiring much more expensive wooden support beams.  The A-frame, pyramid, conical, or igloo designs with narrowing walls as they reaches their peak height would close the top of a straw structure while providing adequate headroom for a person of your size.  Somewhat more technique is needed to complete these designs, but their complexity should not be overwhelming to a pig of your intelligence.

I estimate the floor area, enclosed volume, and bale count for these four closed designs as:
Equilateral A-frame, 15X15 exterior base, 15 feet height: 144 sq.ft. with 1370 cu.ft. (1190 below 8 feet) from 130 bales (some cutting required);
Equilateral pyramid, 15x15 exterior base, 15 feet height: 144 sq.ft. with 760 cu.ft. (695 below 8 feet) from 109 bales;
Equilateral conical, 15 feet exterior diameter, 15 feet height 113 sq.ft. with 600 cu.ft. (545 below 8 feet) from 130 bales (shaping required);
Hemispherical igloo, 19 feet exterior diameter, 9.5 feet height 200 sq.ft. with 1040 cu.ft. (max height is 8 feet) from 162 bales (shaping required).

Heating and cooling cost are largely a function of the cubic volume.  Your best bargain for floor space as a ratio of the enclosed volume is the igloo design (about 1:5.2) without volume loss above 8 feet, but that is the most difficult to build and requires the largest lot size.  The equilateral pyramid is the most economical and relatively easiest erected with a similar floor-area:volume ratio.  It is my recommendation for your needs and budget.

Recognizing the limiting time constraint you have placed on this project in order to meet the demands of your musical career, it would be possible to forego the usual coating of the straw with stucco, mud, and/or plaster.  Unlike the speed with which the walls can be erected, this spackling phase is very labor-intensive.  There is an increased risk of damage from weather, rot, and foraging animals with an appetite for straw in the absence of this protective barrier, but if your residency plans are short-term, the rates of depreciation may be essentially immaterial  to your needs.  Similarly, the expense of a water-tight foundation on which to rest the house may also be a waste of money and time, given the short occupancy you anticipate before your career blossoms after the coming winter season.

In summary, I would encourage you to proceed with your plans to build your house of straw.  It is suitable to your lifestyle, timeframe, and budget.  I look forward to your house-warming party; please remember to invite me.

At your humble service,
Zeke Midas Woolf, RA/AIA