KO’s non-fog 100% cotton t-shirt mask DIY

mask pattern pdf complete

The premise of this design is to create a minimum of 50% viral blockage face mask with materials one might find in the home when one is not able to leave the home due to shelter-in-place. Using a T-shirt one can create several washable, sterilizable facemasks suitable for people wearing glasses so that the glasses are not fogged by the breath coming from the facemask. Without a middle nose bridge and without elastic which breaks down in hot water quickly, this design should provide multiple uses between washing. They can be sterilized in a pressure cooker for 15 minutes or boiled. The mask is a derivation of the Fu mask.

We got feed back! Before you sew, read it at the end.

Begin by taking your T-shirt and cutting the bottom hem off close to the interlock stitching. Mark at least four courses 1 inch wide from the bottom of the cut edge of the T-shirt. These strips will be your straps to hold the mask in place. Cut the 1 inch strips out and then pull them tight and you will see they turn into “shoestrings”. 20200401_14275920200401_14325320200401_145029

Put them aside and lay out the pieces as you would cut them from the T-shirt. If the T-shirt has a design that isn’t heavily preprinted with plastic ink you can use that as a decorative detail, so there no fast rules for cutting out the pieces. I found  I could cut two complete masks out of the sleeves.

The pattern provided is both the front and the back piece of the mask.

Cut two pieces of each pattern piece, the mindful of the print side in the backside of the T-shirt fabric.



I suggest sewing in this order: stitch the large curved edges of the front and back parts of the mask together. Stay stitch along the bottom edges and turn the small edge of the back of the mask at the full mark and stitch that down. I suggest stitching the bottom edge of the pocket to give it more strength at this time.

For the front part of the mask, fold what will be the pocket up and iron or shape it on your knee and then stitch down the sides to the outside edge of the mask.

At this point both pieces will be the same size.

Next is putting on the straps. As long as you have the bottom hem of the T-shirt to work with, use that for the top strap that goes above the ears. If it is sized snugly to the head, the wearer will not have to futz with it when they put the mask on.


I cut the t-shirt hem at 12.5 inches for the top strap. Make sure you place the top strap 10mm down from the cut edge. Because you’ve already finished the bottom edge of the mask the placement of the strings at the bottom are not crucial.

The shoestrings can be measured extra to tie a knot in it for adjustment,& they stretch. I cut mine at 20 inches they could’ve been a little bit shorter.

With the straps sewn at the edges, you can tuck them in and sew around the sides and top of the mask.

Note the seam allowance for the two little lobes at the top is only 8 mm. This is so you don’t have to cut excess fabric away. It will add a little puffiness next to the lobes which will weigh them down to make them more effective.

You’re almost done. Turn the mask inside out and pull all the corners and edges out to the extent of the seams and flatten them, or iron if you have one. Now carefully sew about a 1/16th of an inch or 2 mm in from edge all along the sides and the top. Then go back to the top edge in stitch across that little gap at the bottom of the lobes.

WAIT! one last adaptation! I found some poly fill pillow stuffing and place a small amount [about the size of a dime] in the lobes BEFORE that last step. It gives the lobes  more volume.


Bingo you’re done. Try it on for size and see how it fits. Take the two little lobes that are sticking up to the bottom of your eyes and just push them down alongside your nose. Exhale to make sure your glasses aren’t fogging up. Just as with the commercial facemasks you may have to adjust it to your face to get it to work right. I tie a half hitch on the bottom shoestring and adjust to my neck.


You’ll find it’s comfortable, yet snug. If you like how it feels when you’re ready to put it to work sterilize it by placing it in on the steam rack in a pressure cooker and full steam for 15 minutes, simply boiling in water will work but I don’t know how long that will take.  Now you’ve got it down, why don’t you use the rest of the fabric of your T-shirt and make masks for your friends?

I use chopsticks to remove the steaming the piping hot masks from the pot and dry them over the heater, but you might have a clothes dryer. When you take them out, make sure you have your little rubber gloves on, sprayed with alcohol, to ensure they are sterile. Then put them in a new sealable plastic sandwich bag that will be used to store the mask.

One last step.  If you think this is a good pattern please share it wildly and if you can make an improvement please send a note and add your change to the design.

When you share them, remind the receiver that these are not throw away masks, they do not go directly to landfill. Also, you have the tag on the T-shirt that says the fabric content, and you can include that information on the bag so people know it’s 100% cotton and you might even have T-shirts that are 100% organic cotton.

Additionally, if you have access to a filter paper that will increase the level of protection, you can cut it to the pattern here, and slip that inside the mask and behind the little pocket you sewed in so it will stay in place. It can be removed and tossed before the mask needs to be washed again. Choose love!Creative Commons License mask filter improved pdf insert

Field testing results

Feedback from field testers was disappointingly vague, however, this bit was useful!

“First of all, thank you so much for the masks! Our hospital in Tahoe has received many homemade masks, so we’ve had a chance to compare with other designs.

Our thoughts:

-Your mask feels much more form fitting, and likely does a better job of filtering. The other masks are more simple, so mostly just protect from droplets.

-We love the shape. The space for the nose is appropriate and there is enough fabric to get good chin coverage.

-With glasses on, we still had fog. We wondered if adding some flexible metal around the nose to keep it close to the face, might help. However, this is an ongoing issue for all masks, even ones that have been widely researched and hospital-approved. I recently spoke to one of our oncology surgeons (who wears glasses), and she said the only thing that works is adhesive. I’ve seen some nurses taping the upper part of the mask to their face.

-The upper strap of the cat mask fit my head well, but was too small for Kurtis. Adjustable upper and lower straps would work for all.

-We really appreciate the ability to boil them to sterilize.

I think we will be using these for a long time to come. We appreciate your care and support!

Carla and Kurtis”

I also learned that while the mask worked great while mowing with hayfever, it fogged my glasses while bending over while loading mulch. Other feedback indicated glasses will fog if worn while jogging. The space between lobes is crucial and some test versions didn’t fit my eastern/northern european nose as good as others.

I am back at work with the bees now so further development is up to the reader!

Choose love!

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