Cotton building insulation © Daniel FriedmanPhoto Guide to Identification of Cotton Building Insulation

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

Cotton insulating batts:

This article illustrates and describes how to identify, inspect, and evaluate cotton insulation materials in buildings. We provide photographs and descriptive text of cotton insulation and other insulation products to permit identification of these materials in buildings.

This document assists building buyers, owners or inspectors who need to identify various kinds of insulating materials and who need to evaluate the condition of building insulation by simple visual inspection.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

COTTON INSULATING BATTS - Cotton building insulation should not be mistaken for asbestos

mineral wool building insulation

Cotton building insulation was sold by the Lockport Cotton Batting Company under the product name Lo-K®.

Cotton insulation may have been made, sold, and distributed by other manufacturers or distributors of building insulation in the late 1940's, including Bristol Insulation, Cary Insulation, Insulation Industries, Inc., Janesville Cotton Mill, Sears Roebuck, and Gilman Brothers Co.

Cotton insulating batts were installed in many homes in the U.S. from about 1935 to 1950, and this material has recently seen a surge in new interest as a "green" building material.

What is the insulating value of cotton batts?

Cotton insulation batts sold as Lockport's Lo-K® ranged in thickness from about 1/2" to 20" and its density ranged from 4.19 to 2991 kg· m-3 (about 1/4 pound per cubic foot up to more than 100 pounds/cubic foot(?))The heat transmission of various insulating materials including cotton can be viewed at the NIST website. NIST data shows that cotton insulation had a resistance to heat transfer ranging from 0.025 to 9.1 h· ft2· °F· Btu-1 (depending on the thickness of the product). I'm guessing from the data that this translates into modern "R" values of about 0.5 per inch.

Currently marketed cotton insulation costs about 20% more than fiberglass insulation of roughly the same dimensions, and has a lower R value of R 3 to R 4 per inch of cotton insulation compared with an R value of R 5 to R 7 per inch for fiberglass batts.

To compare insulating material R-values see our Table of Properties of Insulating Materials

Is Cotton Insulation Batting a Green Insulation Building Product?

Well sure it is insofar as we're using a natural, grown material rather than an insulation product made from petroleum products (plastics, foams). But "green" is a little tough to pin down.

For example, when we evaluate the greeness of cotton insulating batts, the "green" claims we've read did not consider the petroleum product consumption in the production of cotton, the transport of cotton to the insulation producer, nor the effects of use of pesticides and fertilizers. These added complexities confound the environmental claims of lots of products, not just building insulation.

The health claim, that cotton produces fewer problem particles than fiberglass sounds reasonable, but a study of the health effects that plagued workers in 20th century cotton mills leaves some questions about this assertion as well, at least for the producers of the product. The fiber release of any insulating product depends a lot on where and how it was installed and on its condition and its exposure to disturbance.


Continue reading at CELLULOSE INSULATION FIRE RESISTANCE or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.


Or see INSULATION R-VALUES & PROPERTIES for an extensive table describing the properties of different insulating materials used in buildings.

Suggested citation for this web page

COTTON INSULATION BATTS at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia


Frequently Asked Questions (FAQs)

Click to Show or Hide FAQs

Ask a Question or Search InspectApedia

Questions & answers or comments about the properties & identification of balsam wool & other wood product insulation materials.

Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.

Search the InspectApedia website

HTML Comment Box is loading comments...

Technical Reviewers & References

Click to Show or Hide Citations & References

Publisher's Google+ Page by Daniel Friedman