Face Masks and Inserts – Why Use Wool Felt?

Disclaimer: This product has not yet been tested for medical standards. Wearing a protective mask will not prevent someone from contracting COVID19, but it will help stop the spread. DIY face masks are not intended to treat, cure or prevent diseases or viruses.

“My mask protects you – your mask protects me”

There is a shortage of medical face masks and hospitals are in desperate need to provide protection for their staff during this outbreak. Many people are now dealing with “last resort” DIY face masks, including some hospitals.

We have had customers inquire about making protective masks using felt. In light of this, here are some of our personal recommendations for creating felt masks and filtration inserts.

Felt can be made of wool or from synthetic fibers such as acrylic (craft felt). These different materials will behave differently, so it is important to know what you have. Our first recommendation is to use a felt with a high wool content. Wool felt is known for its comfort, protection, maintenance and reusability, and ecological factors.

Benefits of Using Wool Felt


Tests have shown that after 3 hours of wearing a face mask that utilizes wool, there is no noticeable condensation build-up, which is common with typical surgical and synthetic masks.

Wool is naturally more breathable and moisture-wicking than other textiles, as it absorbs the sweat and evaporates it into the air.


Studies show that although DIY masks capture fewer particles than a surgical mask, they still block more than 50% of particles when worn.

According to the Reusability of Facemasks During an Influenza Pandemic: Facing the Flu, “Respirator and medical mask filters are typically composed of mats of nonwoven fibrous materials, such as wool felt, fiberglass paper, or polypropylene. The material creates a tortuous path, and various mechanisms result in the adhesion of particles to the fibers without necessarily blocking the open spaces, still allowing air to flow easily across the filter (Revoir and Bien, 1997).”


After use, we highly recommend that you sterilize the mask and/or insert by placing them in a boiling pot of water for a few minutes (5-10 minutes) WITHOUT STIRRING. This is very important with wool material as it will start a felting process and affect the wool. However, you may gently push down the mask and/or insert to keep it fully submerged in the boiling water.

Once disinfected, hang the mask overnight to dry. DO NOT twist or wring the mask, rather roll the mask between a cloth to remove excess water. The wool may develop surface fluffs and pills. Never pull off by hand; instead use scissors to cut them off.

Note: Washing wool in hot water will not remove any of the scales on the fibers.


Wool felt is a natural and sustainable material which means that it will break down naturally. When the mask and/or insert has become too worn for wearing, you can burn or compost the wool. Or can be used directly in potted plants or gardens; Wool can hold water, increases oxygen in the soil, acts as a slow release fertilizer, and repels slugs and snails.

The Felt Store’s Take

Here at The Felt Store we constantly test our products to benefit our customers. The mask shown in this article was created using a 2-layer cotton material for the mask and our F-5 industrial felt in 1/8” thickness for the insert.

Both materials can be boiled to sterilize the mask and insert. This makes it easier to reuse for daily protection.

F-5 industrial felt is a heavy duty 95% wool felt used for industrial purposes. It is a less dense felt making it more breathable than harder F-1 and F-3 felts.

The remaining 5% of fibers are known as “card waste”. This consists of recycled wool, cotton, rayon/viscose and sometimes even bits of vegetable matter and polyester.

We used our F-5 industrial felt for the filtration insert due to the wool content and density. Our 100% wool designer felt may seem to be the better option however, it is too dense and will not allow proper air flow.

We hope this article helps you in your search for DIY face mask materials. Stay safe!


F-5 Industrial Felt By Linear Foot
from $27.10 USD


F-5 Industrial Felt By Linear Foot
from $38.00 CAD


  • Anonymous

    Hi Kathryn! You can find the width for our F-5 Industrial Felt on the product page. It is 66" wide on our U.S. site and 72" wide on our Canadian site due to stock availability. If you have any more questions feel free to contact us at sales@thefeltstore.com.

  • kathryn

    it says linear foot but linear only measures length. what is the width?

Leave a comment

Please note, comments must be approved before they are published

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.