One of the characteristics of Hair Canvas not found in ordinary canvas is a one way grain.
True Hair Canvas has large, thick fibers running width wise. With smaller, more flexible fibers going length wise.

What this does in a Kilt is give the longitudinal stretching resistance needed between the straps while stiffening the Kilt up and down and minimizing rolling and puckering.

An ordinary canvas will offer the longitudinal stretch resistance but not aid to minimize rolling and puckering.

If you attempt to fold Hair Canvas it will be easy to fold one way but stiffer in the other direction.

This stiffer direction is placed vertically to help support the waist and Fell area of the Kilt and keep it from rolling down over itself or developing puckers of the aprons over time.

I find that most higher end fabric stores either carry hair canvas or will order it for you. The problem I have found is getting the sales people to understand what you are talking about in the first place. Most of them do not sew, have never made a tailored garment and only know how to ring up your purchase in the register.

If you have to, visit your local custom, Traditional Kiltmaker and ask for a scrap of Hair Canvas. Then take that sample to the fabric store.

Alternately you can ask Barb, Matt or Myself and we can mail you a small scrap.