Keeping cool cats warm
Winter shelter is critical for feral and stray cats living in frigid climates and can help them thrive despite the low temperatures. Listed here are mostly examples of inexpensive, do-it-yourself shelters that can be built in a matter of hours or less. All designs share three essential qualities - they're well insulated, have minimal air space and are waterproof. They need to be well insulated to trap the cats' body heat, have minimal air space so there isn't too much empty room to heat up, and be waterproof so the interior remains dry. Further down this page, you'll find info on placement of shelters, insulating materials to place inside your cat cabins, extra protection for extreme cold and flap doors. For more on winter care, see how to stop freezing water. For New York City area caretakers, check out local options for purchasing pre-fabricated winter shelters and straw.
Neighborhood Cats Winter Shelter
Neighborhood Cats was founded in New York City with its cold Northeast winters. When we first started out, Karin Hancock of Port Jefferson, NY, showed us how to turn a Styrofoam sheet used for insulating walls into a great winter shelter that can comfortably house three or four cats. A single sheet (8 ft. long, 2 ft. wide and 2 in. thick) is cut up into all the pieces needed. Adhesive linoleum tiles are added to the floor, then all the pieces are attached together with silicone glue. A coat of deck paint for camouflage and protection finishes the job. This shelter has gotten the cats through many a tough winter! Follow our instructions and see the PictureTrail created by volunteer Arjun Ray. Use of a table saw for cutting up the Styrofoam is recommended to ensure straight edges.
CSM Stray Foundation Winter Shelter
Turn a durable storage bin (like the Husky Heavy Duty 54 Gallon Storage Tote) into a warm winter hideaway with this design inspired by CSM Stray Foundation. The interior walls, floor and ceiling are lined with pieces of 1 inch thick Styrofoam cut from a sheet 8 feet long by 2 feet wide. Precise edges are not necessary so the pieces can be hand cut. Straw is stuffed in the bottom and a doorway cut in the side. Like most winter shelters, it is lightweight and should be weighed down with a board or heavy rock. Follow the instructions to build (photo by Carole Milker, CSM Stray Foundation).
Feralvilla (for purchase)
Feralvilla manufactures the best-selling outdoor cat shelter on the market. It's made of wood composite, is pre-primed for painting, and assembles in 15 to 30 minutes with a screwdriver. There are two levels. Cats enter the lower level from outside, then climb up through an inner opening to the fully insulated upper floor. Shingle roof is optional. The wood composite material, LP's SmartSide, is environmentally friendly and uses a low toxicity resin to bind the fibers.
Styrofoam shipping boxes
Perishable items like meat and fish are often shipped in Styrofoam boxes. The containers used to ship Omaha steaks are an excellent example. Styrofoam shipping boxes can be found at supermarkets, fish stores and butcher shops. Even vaccines are packed in them, so your veterinarian might be a good source as well. These well insulated crates can be easily transformed into feral cat winter shelters:
(1) Using a utility knife or box cutter, open a doorway in one of the short sides of the box, approximately 6 inches by 6 inches. Keep the bottom of the doorway a few inches above ground level, to prevent flooding in the event of rain.
(2) Permanently attach the top cover to the main body of the box with silicone glue. The silicone will seal the lid and make the shelter waterproof.
(3) To camouflage and further protect the shelter, apply a coat of an appropriately colored deck paint.
When time is of the essence - a bad storm or sudden cold snap may be arriving soon - an adequate temporary shelter can be quickly put together. You'll need a cardboard box, a plastic drop cloth at least 3 millimeters thick or contractor trash bags that are three millimeters thick, duct tape and shredded newspaper. Follow these instructions:
(1) Take the cardboard box and tape all the seams shut with duct tape. Cardboard is actually good insulation.
(2) Wrap the box completely with the drop cloth or trash bags, making as few seams as possible. Secure onto the box with duct tape, liberally and tightly wrapping the tape around the sides of the box and sealing any seams in the plastic. This will make the shelter waterproof.
(3) Cut a doorway in one of the shorter sides of the box approximately 6 inches by 6 inches, leaving the bottom of the doorway a few inches above the bottom of the box to prevent flooding. Use duct tape to secure the loose plastic around the opening you just made.
(4) Place shredded newspaper inside the box, filling it up to the bottom of the doorway in front and a little higher towards the back. The cats will gain added warmth by burrowing into the newspaper.
For added insulation, start by placing a slightly smaller cardboard box inside a larger one and fill the gap between them with rolled-up newspaper. Then proceed with steps 1 through 4, above, being sure to cut the doorway through both boxes. If possible, place your cardboard shelter beneath something that will shield it, like a porch or tree. Raise it off the ground a few inches by placing it on a pallet, bricks or something similar. Weigh the shelter down with a heavy rock or a few bricks, but nothing heavy enough to crush the roof. Once the crisis has passed, replace with more permanent shelter.
Other do-it-yourself designs
Feral cat caretakers are an inventive lot and there are many other designs for winter shelters that make use of Styrofoam and durable storage bins. The level of skill with construction and the need for power tools varies among them. Here's some that caught our eye:
Storage bin with a flower pot entryway by Bushwick Street Cats (photo)
Foam coolers from Lo-Boy by Krista Rakovan
One storage bin stacked inside another by Spay and Stay
Storage bin with a windbreak interior panel by John V.
Where and how you place your shelters could go a long way towards encouraging your feline wards to use them. For starters, put the shelters where the cats are already used to going, like near their feeding station or in an area you know they like to hang out. Putting them near the feeding station has the advantage of limiting how far the cats have to travel to eat during snow or other inclimate weather. Don't put the shelters out in the open, like in the middle of a yard or lot, but under or against something, like a building, fence, tree, porch, bush or some type of overhang. Ideally, the spot will be out of the wind but exposed to the sun.
One idea is to position two shelters about one and a half feet apart with the front doors facing each another. Cover the gap between them with a board spanning their roofs (see photo above) to prevent wind, snow or rain from getting in.
To prevent flooding, raise the shelters off the ground by placing them on pallets or bricks. If you do this, make sure the shelters are stable and not wobbly when raised. A unsteady shelter could discourage cats from entering. If your shelters are lightweight, such as those made from Styrofoam, place bricks or other heavy objects on the roofs to weigh them down.
You can also camouflage the shelters with burlap, branches or twigs and, if the surfaces allow, by painting them with an exterior deck paint to blend in with their surroundings. Encourage your cats to start using the shelters by sprinkling catnip at the entrances.
Interior insulating materials
Your cats will be warmer and cozier if they can burrow into insulating materials you've placed inside their shelters. Straw is perfect - it's loose, dry and provides added insulation. Shredded newspaper will work as well. What you should avoid are towels, blankets, folded newspaper or similar items that lie flat on the floor. When cats lie on top of these materials, their body heat is drawn out, making them colder not warmer.
Remember that straw and hay, which is used for animal feed, are not the same thing. Hay should never be used as insulating material because, unlike straw, it draws and holds moisture. As a result, it can become moldy and cause allergic reactions, including nasal sores. Straw can be found at most large garden centers, such as Home Depot and Lowe's. Craft stores like Michael's and AC Moore sell small bales to be used as decoration. Another option is to seek out stores, restaurants or banquet halls whose fall displays use bales of straw. Instead of throwing it away after Thanksgiving, like they usually do, perhaps they'll donate it to you! You can also order a 4 lb. box of straw, enough for about two small shelters, from Kitty Tube (photo, above). Free shipping is offered.
An exception to the "nothing flat on the floor" rule is a self-warming pet pad. Made of materials which absorb and retain a cat's body heat, examples include the Carolina Pet Company Purr Padd and the K&H Pet Pad. Another way to add warmth is by wrapping Snuggle Safe Microwave Heat Pads in cloth and tucking them in the shelter. After being microwaved, these plastic discs give off heat. The Snuggle Safe pads can also be used to stop water from freezing.
A creative option comes from Maverick Cats: Encounters with Feral Cats by Ellen Perry Berkeley: stuff a pillow case with packing peanuts. When a cat lies on it, the peanuts will conform to her shape and wrap her in warmth-capturing insulation. Note that packing peanuts used to always be made from Styrofoam but are now increasingly made from starch, which dissolves in water. To prevent the peanuts from getting wet and melting away, place and tie them into a plastic bag, then put the bag inside the pillow case.
Extreme cold (Mylar blankets)
In far north regions where extreme cold is often the norm during the winter, shelters can be made warmer by lining the interior walls, floor and ceiling with Mylar blankets. Mylar is a thin polyester material that traps body heat and reflects it back to its source. The most common use of Mylar blankets is in winter survival kits - wrapping one around yourself can keep you warm in frigid conditions. They're very inexpensive (usually no more than a dollar or two each) and can be found at a variety of merchants on Amazon. They can be cut to fit interior shelter walls then attached with non-toxic glue, such as Weldbond Universal Adhesive, or freezer tape. Search Amazon to find Weldbond glue. Be sure to tuck in any loose material at the seams so the cats won't be tempted to pull or chew at it.
Putting a cover, or flap, over the doorway of your shelter will help keep cold air out and warm air in. A piece of heavy vinyl or rubber, like a car's floor mat, will work. The material has to be thick enough to provide some insulation but light enough for the cats to easily pull or push it open. How the flap is attached will depend on the type of material the shelter is made of. With Styrofoam, drill two holes through the mat and above the doorway and insert plastic nuts and bolts, like the kind used to attach toilet seats to toilets. With storage bins, again drill two holes and use any suitably sized nuts and bolts. Or, at least temporarily, you can use duct tape to attach the flap. Do not attach a flap door, however, until after the cats have gotten used to going in and out of the shelter. Otherwise, it might deter them from going in and exploring.