Installing wool insulation is easy, as it is light weight, cuts easily, and requires no hazmat suit!
Sheep wool insulation is sized similar to other roll and batt insulation products, as most are designed to fit within standard 16″ on-center wood framing or 24″ on-center wood framing. In a new house, such framing will typically (within standard industry allowances) result in a space between the studs, joists, or rafters of about 14.5″ for 16″ on-center or 22.5″ for 24″ on-center. In an old house, one in which the framing members are a full 2″ thick instead of the 1 3/4″ two-bys used today, this space will more likely be 14″ or 22″.
Regardless of the age of the house or the on-center spacing attempted by the builder, the actual spacing will vary from house to house and even from one cavity to the adjacent cavity, and the customer is responsible for knowing their spacing and understanding that insulation products are sized per industry standard. This spacing will be a factor in determining how much support is needed to keep the insulation in place, as will be the smoothness or roughness of the framing members (typically smooth today and rough in the yester-years). Spacings wider than standard and/or smooth framing will reduce the ability of roll and batt insulations to “stand in place” in a wall cavity. This is true of rafter and ‘underneath’ joist installations as well, though both these applications should be supported against gravity.
As sheep wool insulation products are typically not faced, when support is needed the edge of the roll or batt may be stapled to the inner edge of the adjacent framing members. In addition to, or instead of, wire insulation supports may also be used, especially for rafter or ‘underneath’ joist installations.