Ad-hoc Simple Washable Respiratory Mask From Household Material

Technical Short Guide

Jakob Möhring (Berlin, Germany)

April 2020     ( updated: 2020-04-25 18:33:35.165 )

Correspondence to:


The US Centers for Disease Control and Prevention (CDC)1 and the World Health Organization (WHO)2 recommend covering the mouth and nose with homemade masks or cloth in settings where commercial facemasks are not available as last resort to protect against COVID-19 and other influenza infections. But instructions on how to effectively use household materials for this purpose are rare to find.

The following technique shows how to fold a T-shirt (or cloth) to use it as a respiratory filter and wear it as a tight fitted and fairly well sealed respiratory mask using cut-up inner tube. Both low-cost materials are readily available and can be hot washed to sterilize in low resource settings. The only tool needed is a knife or a pair of scissors to cut the inner tube.


Two rubber straps are cut from inner tube, long enough to reach around the head and to easily tie a simple half knot at the ends: one from the nose to the back of the head, the other from under the chin to the top of the head. Any length short of one meter (or three feet) should be practical. The strap that will go over the nose should have a minimum width of 3 to 4 centimeters (around 1+1/2 inch) to maintain a reasonable width when folded in half in cross direction. The produced straps are slightly bent with an arched cross profile, both contributing to a better fit.

A cotton T-shirt is folded into to a triangular shape with two diagonal folds, resulting in 6 to 8 layers of cotton in the center: the lower right-hand corner of the shirt is placed to the upper left side of the neckline, the lower left-hand corner is placed on the upper right side of the neckline, forming a V-shaped space within the neckline. The T-shirt is then double-folded from the back of the neckline downwards closing the open V-shape. The contour of the rolled-up neckline (with a dent in the middle between two bulges) fairly matches the facial contour of the nose to the cheekbones.

The folded filter is put on the face like a bandit’s mask, with the folds on the inside. Placing the dent (in the center of the long edge) on the nasal ridge (dorsum) the two bulges are padding the spaces left and right between the nose and the cheekbones. If possible, the filter is provisionally tied behind the neck (with its sleeves).

The rubber strap with the preferable width of 3 to 4 centimeters (around 1+1/2 inch) seals the filter to the face. It should overlap the filter one-half its width from the nose to under the ears, and being tied with a simple half knot at the back of the head.

On the ridge of the nose the strap is folded in half crosswise, bending the upper edge inwards around the edge of the fabric. The resulting twists to the left and right of the nose fairly close the gaps between the nose and the cheekbones.

A second rubber strap is tied from under the chin to the top of the head to hold the filter in place and to support a tight fit of the mask.


Ad-hoc mask from T-Shirt and cut-up inner tube
Folding a T-shirt or cloth to be used as respiratory filter


Cotton T-shirt has been described as a suitable household material for handmade face-masks.3 Depending on its design even a simple respiratory mask made of several layers of cotton T-shirt can provide a measurable level of protection.4 Eliminating leakage around the mask is critical for reducing exposure to infectious bioaerosols5, as properly fitted respirators provide significantly higher protection.6 An improvised face mask should only be viewed as the last resort to protect against infectious disease in settings where commercial masks are not available.7 8

Individual ad-hoc masks of this type might be less effective because of variations in material, assembly, facial structure, and handling. However, a mask of this type is a physical barrier, should achieve a reasonable fit factor, and therefor may reduce exposure to infectious particles.

  1. Centers for Disease Control and Prevention (CDC). Strategies for Optimizing the Supply of Facemasks (Crisis Capacity Strategies). Page last reviewed: March 17, 2020 .↩︎

  2. World Health Organization (WHO). Pandemic influenza preparedness and mitigation in refugee and displaced populations. WHO guidelines for humanitarian agencies, Second edition; Geneva, 2008.↩︎

  3. Davies, Anna & Thompson, Katy-Anne & Giri, Karthika & Kafatos, George & Walker, James & Bennett, Allan. (2013). Testing the Efficacy of Homemade Masks: Would They Protect in an Influenza Pandemic?. Disaster medicine and public health preparedness. 7. 413-418. 10.1017/dmp.2013.43.↩︎

  4. Dato, V. M., Hostler, D., & Hahn, M. E. (2006). Simple Respiratory Mask. Emerging Infectious Diseases, 12(6), 1033-1034.↩︎

  5. Booth, C & Clayton, M & Crook, Brian & Gawn, Jonathan. (2013). Effectiveness of surgical masks against influenza bioaerosols. The Journal of hospital infection. 84. 10.1016/j.jhin.2013.02.007.↩︎

  6. Gawn, J.M., Clayton, M., Makison, C., & Crook, B. (2008). Evaluating the protection afforded by surgical masks against influenza bioaerosols Gross protection of surgical masks compared to filtering facepiece respirators.↩︎

  7. MacIntyre CR, Seale H, Dung TC, et al. A cluster randomised trial of cloth masks compared with medical masks in healthcare workers. BMJ Open 2015;5:e006577. doi: 10.1136/bmjopen-2014-006577.↩︎

  8. World Health Organization (WHO). Rational use of personal protective equipment for coronavirus disease (COVID-19) and considerations during severe shortages. Interim guidance 6 April 2020. WHO reference number: WHO/2019-nCov/IPC_PPE_use/2020.3↩︎