Winter Shelters for Outdoor Cats: DIY Guide
Step-by-step instructions to build inexpensive, effective shelters for cats during cold weather.
As temperatures drop, outdoor and community cats face serious challenges surviving the winter months. Providing warm, dry shelters can be the difference between life and death for these resilient animals. Fortunately, you don't need to be a master carpenter or spend a lot of money to create effective winter shelters for cats.
In this guide, we'll walk through three different DIY cat shelter designs, from simple to more advanced, using readily available materials. Each design has been tested by cat rescue organizations and proven effective in various winter conditions.
Important: Even with good shelter, outdoor cats need extra calories during cold weather. Always provide food and fresh water (use heated bowls in freezing temperatures) alongside any shelter you build.
In this guide:
Key Principles for Effective Cat Shelters
Before diving into specific designs, let's understand what makes a winter shelter effective for cats. Regardless of which design you choose, all good cat shelters share these important features:
Size Matters
Shelters should be just large enough for cats to stand up and turn around, but small enough to retain body heat. Aim for approximately 2 feet x 3 feet for a shelter that houses 2-3 cats. Too large, and the shelter won't retain heat effectively.
Insulation is Critical
Effective insulation between the cold ground/outside air and the cats is essential. Materials like styrofoam, straw, or specialized insulation boards work well. Never use blankets, towels, or hay, which absorb moisture and can freeze.
Doorway Design
Entrances should be just large enough for cats (5-6 inches in diameter) but not so large that predators or cold air can easily enter. Doorways should face away from prevailing winds and include a door flap or baffle to block wind.
Elevation
Shelters should be raised a few inches off the ground to prevent heat loss to the cold earth and avoid flooding during rain or snow melt. Bricks, pallets, or pressure-treated lumber work well as a base.
Weatherproofing
All shelters must be waterproof and windproof. Seal any cracks or holes, and ensure the roof has a slight slope to shed water and snow. Consider adding shingles or a waterproof tarp over wooden shelters.
Bedding Material
Straw (not hay) is the best bedding material as it repels moisture and provides excellent insulation. Replace it when it becomes damp or soiled. Never use blankets, towels, or fabric, which retain moisture.
Pro Tip: Consider building multiple smaller shelters rather than one large one. This provides options for cats who may not get along and creates backup shelter if one becomes unusable.
Beginner Project: Plastic Bin Shelter
This simple shelter can be built in under an hour with minimal tools and costs less than $30. It's perfect for beginners and provides effective protection in most winter conditions.
Materials Needed:
- Large plastic storage bin with lid (30-35 gallon size)
- Second smaller plastic bin that fits inside the larger bin with 1-2 inch gap all around
- Rigid foam insulation board (1-inch thick)
- Straw for bedding
- Utility knife or box cutter
- Duct tape or waterproof tape
- Permanent marker
- Measuring tape
Step-by-Step Instructions:
- Prepare the bins: Wash both plastic bins with mild soap and water, rinse thoroughly, and dry completely.
- Cut the doorway: On the long side of both bins, draw a 6-inch by 6-inch doorway about 4 inches from the bottom edge. Use the utility knife to cut out the doorways. Make sure the doorways align when the smaller bin is placed inside the larger one.
- Cut insulation: Measure and cut pieces of foam insulation to fit:
- Between the bottom of the outer bin and the bottom of the inner bin
- Between the sides of the outer bin and the sides of the inner bin
- To cover the inside of the outer bin's lid
- Assemble the shelter: Place the insulation on the bottom of the outer bin, then place the smaller bin inside. Fill the gap between the bins with more insulation pieces. Secure any loose insulation with duct tape.
- Prepare the lid: Attach the insulation to the inside of the outer bin's lid using duct tape. Ensure it's secure so it won't fall onto the cats.
- Add bedding: Fill the inner bin with several inches of clean, dry straw.
- Secure the lid: Place the lid on the outer bin and secure it with bungee cords or weatherproof tape to prevent it from blowing off in strong winds.
Tip: To prevent the shelter from blowing away in strong winds, place a few heavy rocks or bricks on top of the lid. Just make sure they don't compress the insulation inside.
Intermediate Project: Styrofoam Cooler Shelter
This design takes advantage of the excellent insulating properties of styrofoam coolers. It's lightweight, inexpensive, and provides superior insulation in very cold climates.
Materials Needed:
- Two styrofoam coolers (one that fits inside the other with 1-inch gap all around)
- Large plastic storage tote with lid (to protect the styrofoam)
- Utility knife or box cutter
- Duct tape or Gorilla tape
- Straw for bedding
- Waterproof tarp or contractor garbage bag
- Permanent marker
Step-by-Step Instructions:
- Prepare the coolers: Clean both styrofoam coolers and ensure they're completely dry.
- Cut doorways: Mark a 6-inch by 6-inch doorway on both coolers, positioning them so they'll align when nested. Cut out the doorways with the utility knife, making clean cuts to prevent styrofoam debris.
- Create the nested structure: Place the smaller cooler inside the larger one, aligning the doorways. If there's space between the bottoms, add pieces of styrofoam or bubble wrap for additional insulation.
- Secure the coolers: Use duct tape to secure the smaller cooler inside the larger one. Tape around the doorway edges to create a smooth entrance.
- Prepare the plastic tote: Cut a doorway in the plastic tote that aligns with the doorways in the styrofoam coolers. The tote will protect the styrofoam from moisture and physical damage.
- Waterproof the shelter: Place the nested coolers inside the plastic tote. Cut a piece of tarp or use a contractor bag to cover the top of the coolers before putting the plastic tote lid on. This provides extra waterproofing.
- Add bedding: Fill the inner cooler with several inches of straw.
- Secure the lid: Place the lid on the plastic tote and secure it with bungee cords or weatherproof tape.
Advantage: Styrofoam provides excellent insulation, making this design particularly effective in very cold climates. The plastic tote protects the styrofoam from UV damage, moisture, and curious animals.
Advanced Project: Wooden Shelter
This durable wooden shelter requires more tools and carpentry skills but will last for many years with proper maintenance. It's ideal for permanent colony locations or areas with harsh winters.
Materials Needed:
- Exterior grade plywood (½ inch thick) - one 4'x8' sheet
- 2x4 lumber for framing - approximately 16 feet
- Rigid foam insulation board (1-inch thick)
- Roofing material (shingles or metal roofing)
- Exterior wood screws
- Waterproof wood sealant or exterior paint
- Door flap (rubber mat or heavy vinyl)
- Straw for bedding
- Basic carpentry tools (saw, drill, measuring tape, etc.)
Step-by-Step Instructions:
- Create a plan: Design your shelter to be approximately 24" wide x 24" deep x 18" high, with a slightly sloped roof for water runoff.
- Cut the wood: Cut the plywood into pieces for the floor, walls, and roof according to your plan. Cut 2x4s for framing the structure.
- Build the base frame: Create a rectangular frame with 2x4s for the base, ensuring it's square. Attach the plywood floor to this frame.
- Add insulation to the floor: Cut rigid foam insulation to fit inside the base frame, then cover with another piece of plywood to create an insulated floor sandwich.
- Build the walls: Frame the walls with 2x4s, including a doorway opening (6"x6") on one side. Attach plywood to the outside of the frame.
- Insulate the walls: Cut and fit rigid foam insulation between the wall framing, then cover with plywood on the inside to create insulated wall sandwiches.
- Create the roof: Build a slightly sloped roof frame, insulate it, and cover with plywood on both sides. Add roofing material on top for waterproofing.
- Make the roof removable: Design the roof to be removable for cleaning and maintenance. Use weather stripping around the edges to prevent drafts.
- Weatherproof everything: Apply exterior wood sealant or paint to all exposed wood surfaces, including the bottom of the floor.
- Add a door flap: Cut a piece of rubber mat or heavy vinyl slightly larger than the doorway and attach it at the top of the opening to create a swing door.
- Elevate the shelter: Place the shelter on bricks or pressure-treated lumber to raise it off the ground.
- Add bedding: Fill with several inches of clean, dry straw.
Pro Tip: For extra insulation in extremely cold climates, line the inside walls with reflective insulation (like Reflectix) before adding the straw. This reflects the cats' body heat back toward them.
Shelter Placement and Maintenance Tips
Building the shelter is only half the battle. Proper placement and maintenance are crucial for ensuring cats actually use the shelter and remain safe throughout winter.
Optimal Placement:
- Position doorways away from prevailing winds
- Place in quiet, low-traffic areas where cats already frequent
- Locate near feeding stations but not too close (to avoid attracting predators)
- Position in areas with morning sun exposure if possible
- Place behind windbreaks like bushes, fences, or buildings
- Elevate shelters off the ground by several inches
- Ensure the shelter is level and stable
Regular Maintenance:
- Check shelters weekly during winter
- Replace wet or soiled straw promptly
- Clear snow from entrances and roofs after storms
- Check for and repair any damage to the structure
- Ensure door flaps are functioning properly
- Monitor for signs of predators and relocate if necessary
- Clean thoroughly and store dry during off-seasons
Important Safety Note: Never use electric heating pads or heat lamps in outdoor cat shelters. They pose serious fire hazards and can cause burns. If additional warmth is needed, consider microwavable heating discs specifically designed for pet shelters, which stay warm for several hours and don't require electricity.
Downloadable Resources
Detailed Building Plans
Complete measurements and step-by-step instructions for all three shelter designs.
Materials Shopping List
Printable shopping lists for each shelter type with estimated costs.
Key Takeaways
- Effective winter shelters must be properly sized, insulated, and weatherproofed
- Straw is the best bedding material; never use blankets, towels, or hay
- Doorways should be small (6"x6") and face away from prevailing winds
- Elevate shelters off the ground to prevent heat loss and flooding
- Regular maintenance is essential for shelter effectiveness
- Proper placement increases the likelihood that cats will use the shelter
Tom Wilson
Cat Rescue Volunteer & DIY Enthusiast
Tom Wilson has been building cat shelters for community cat colonies for over 8 years. As a volunteer with multiple rescue organizations, he has designed and constructed hundreds of shelters for various climates and conditions. Tom regularly conducts workshops teaching others how to build effective, low-cost shelters for outdoor cats.
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