You’ve decided to take the leap and make your own fabric face mask. Congratulations! Now, where do you begin?
Cloth face masks and fabrics used
There are a number of factors to consider, including which fabric mask offers the best protection, best comfort, and, frankly, what is available for you to use. Most sewists prefer to create cotton face masks since this material is easy to work with and easy to find. People who sew regularly often have a stash of cotton fabric close by, but you can also find yards of materials hiding in your linen closet or a kitchen drawer. Also, who doesn’t have a collection of cotton t-shirts to commit to this type of project?
With some stores still closed, you may have to find the items you need within your home or from friends. The good news is that you probably have many great options right at your fingertips, including old jeans, bedding, tea towels, and even a bra.
Experts who have ramped up their studies on materials for fabric face masks have assessed a variety of options, including how to best use them by doubling layers or by combining materials. Their studies give you a wealth of knowledge as you decide how to balance your supply and your level of protection.
Best fabric mask materials to keep viruses out
Let’s start with which materials work best to ensure that your mask does its key job: protecting you from breathing in germs and keeping yours to yourself.
A team at Cambridge University in the UK did extensive testing on a range of fabric face masks that DIYers would use if they couldn’t get their hands on surgical ones. Twenty-one of their volunteers made their own masks, then they were tested for the ability to screen different types of airborne bacteria. They simply put on their masks and coughed, then researchers looked at how many bits of bacteria got through. Each material was tested nine times.
While masks made from cotton t-shirts only blocked one third of the microorganisms that a professional mask would, they still offered better protection than no mask at all. As a comparison, a surgical mask offers a protection rate of 89% to 96%.
Here is how each material fared in terms of mean percent filtration efficiency:
Vacuum cleaner bag: 86% to 94%
Tea towel: 72% to 83% (96% if you double it)
Cotton mix fabric: 70% to 75%
Antimicrobial pillowcase: 66% to 69%
Linen: 60% to 62%
Pillowcase: 57% to 61%
100% cotton t-shirt: 50% to 69% (better if the material is doubled)
Silk: 54% to 58%
Scarf: 48% to 62%
Of course, the mask is more effective if the fabric is more tightly-woven and if the seal around the edges is tighter to your face. The containment of the germs is also affected by the velocity of the cough or sneeze and how big the droplets are that come with them!
“The pillowcase and the 100% cotton t-shirt were found to be the most suitable household materials for an improvised face mask,” the Cambridge study states. “The slightly stretchy quality of the t-shirt made it the more preferable choice for a face mask as it was considered likely to provide a better fit.”
A study conducted in the Netherlands on volunteers wearing both homemade masks made from tea cloths and surgical masks over a three hour period found results similar to those found in the Cambridge study.
What do you have on hand for fabric face masks?
The team at Smart Air took the challenge even further and decided to test even more materials. Ordinarily, Smart Air staff operates a social enterprise that combats air pollution by delivering open-source data and cost-effective air purifiers. However, they put in a lot of time recently to do a full review, similar to the methodology used by the Cambridge researchers.
Their expertise showed that five readily-available materials rose to the challenge: denim, bed sheets, paper towels, canvas, and a shop towel. The thicker and more densely woven the material, the better it screens out germs, however it also makes it harder to breathe through them.
The worst ones are loose-knit scarves, bandanas, and thin cotton t-shirts.
They actually tested 30 different materials, based on requests via a crowd-funding page. Many of the best options for fabric face masks are easy to find within your home. They are listed below, based on different levels of effectiveness.
Here is their ranking of materials based on how well they would filter out particles the size of the deadly Ebola virus:
N95 mask: 99.9%
Surgical mask: 99%
HEPA filter: 99%
HERO coffee filter: 98%
Thick canvas: 97%
Kitchen towel: 96%
Paper towel: 96%
CHEMEX coffee filter: 94%
Medium canvas: 93%
Bed sheet with 120-thread count: 90%
Scott’s Blue Shop Towel: 87%
40D nylon tarp: 84%
Thin canvas: 84%
Bed sheet with 80-thread count: 79%
Two layers of cotton t-shirt material: 77 %
70D nylon tarp: 77%
Bra cup made from muslin and sponge: 76%
Nylon shopping bag: 73%
Quick-dry t-shirt: 60%
Brocade sheet: 57%
3M Disposable Cleaning Cloth: 57%
Dusting cloth: 53%
Merino wool scarf: 49%
Single-layer cotton t-shirt: 47%
Cashmere wool scarf: 43%
Ramie scarf: 24%
You can always test what you have at home with two key exercises:
First, if you hold the fabric up near a window, you can see how closely woven the fibers are. The more light that gets through, the more tiny germs that can travel through the fabric.
Additionally, you can replicate the methods used by the Cambridge and Smart Air researchers by trying to spray droplets through the fabric. Simply fill a spray bottle with water and see how much of a mist gets to the other side. You can combine these results with the information provided here to make a decision on what will work best for you and your family.
Can you breathe while wearing your fabric face mask?
While some materials block out more germs, they may simply be too uncomfortable to wear. However, if you’re not wearing a face mask, you’re not protected at all.
Cotton face masks are preferred since they don’t get as hot and you can easily take in air through them. The tighter the weave, the better the protection, but you give up some comfort when you go that route; while some face mask materials – such as vacuum cleaner masks and coffee filters – increase the screening of germs, you simply cannot breathe through them for long.
Also, the Cambridge study authors found that the stiffness and thickness of vacuum cleaner bags “created a high pressure drop across the material, rendering it unsuitable for a face mask.”
The crew at Smart Air ranked face mask materials on breathability. The ranking landed in this order:
- Six stars: 3M disposable floor cleaning cloth, velvet, quick-dry t-shirt, brocade sheet, wool scarf, HEPA filter, cotton t-shirt (single layer), non-woven polypropylene shopping bag, bandana, scarves, dusting cloth, Scott’s Blue Shop Towel, and canvas
- Five stars: Surgical mask and cotton T-shirt (two layers)
- Four stars: Bra cup and 70D nylon tarp
- Three stars: Paper towels, bed sheets, denim, N95 masks, and kitchen towels
- Two stars: CHEMEX coffee filter and thin canvas
- One star: 40D nylon tarp, HERO coffee filter and thinner canvas
So what is the best combination?
Ultimately, the Smart Air staff recommend the best combination of breathability and filtration as paper towels, denim, and cotton bed sheets. The bra cup also did well, but they doubted many people – especially men – would feel comfortable wearing them in public for long.
They also recommend double layers of a cotton t-shirt when making your own face mask. It is also known for being softer and more comfortable, which means you are more likely to keep it on your face without adjusting it. The less you touch your face, the better, as health officials keep reminding us.
The other option is to create a mask with the ability to insert an extra filter. That would be most helpful when you go into situations when it is harder to keep your physical distance from other people or if you develop a cough and want to make your droplets don’t get past your cotton face mask. For example, you can insert a coffee filter or a HEPA filter into your cotton face mask to add another layer of protection. Just make sure you leave a three-inch slot inside the inner layer of the mask so it is easy to put it in place and remove it later.
Reusing your face mask
You also want to consider how to care for your mask if you plan to reuse it. Cotton face masks are easy to launder and should be washed after a few days of use. Wash them with your regular load and dry them on high heat.
Of course, remove any coffee filters or paper towels you have added as an extra layer. If you worry about other materials unraveling in a washing machine, clean them in warm, soapy water and let them dry in direct sunlight.