Batt insulation
Marks batt insulation, the soft fibrous insulation fitted between studs or joists. It is drawn as a continuous row of loops.
How to read it
The Army's print-reading manual includes thermal and acoustic insulation among its material conventions. The Navy's Builder 3 & 2 course describes batts as flexible insulation made of fibrous material preformed to about 90 to 300 mm (3½ to 12 in) thick, sized for joists 406 or 610 mm (16 or 24 in) apart. The Navy's Engineering Aid course sorts insulation into blanket, batt, loose-fill, reflective and rigid types.
Also searched as: insulation hatch, insulation symbol.
This explains what a symbol represents on a drawing. Conventions vary between firms and standards, and a drawing's own legend takes precedence.
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More blueprint symbols
The same shape elsewhere
Browse symbols drawn with curves and waves or lines.
Sources
- Construction Print Reading in the Field, TM 5-704 / AFM 85-27, Departments of the Army and the Air Force, para. 2-2b; fig. 2-2
- Builder 3 & 2, Volume 2, NAVEDTRA 14044, Naval Education and Training Command, U.S. Navy, ch. 5, insulation
- Engineering Aid 3 (NAVEDTRA 14069), Nonresident training course, April 1995, Naval Education and Training Command (copy hosted by Navy Tribe), Ch. 6, insulation and vapor barriers
- Reading Architects' Blueprints, William S. Lowndes, 1922, International Textbook Company, Scranton (Internet Archive), §5, second-floor details
Researched, edited and approved by Rory Hansen before publishing. Last reviewed September 30, 2026. How we research
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