Building an Outdoor Cat Shelter

Building an Outdoor Cat Shelter

This shelter will accommodate approximately two to three adult cats, depending on how sociable they are.  Smaller totes can be used to make a smaller shelter.  However, the difference in cost usually isn’t significant.

Materials needed (all of these materials should be available at Lowes, Home Depot, or similar stores – Total cost depends on local pricing.)  I’ve noted where I purchased each item in the list below. Only a small portion of the tape, and about 1/2 of the insulation board, are required to assemble a shelter.:

1 – Rubbermaid 31 gallon plastic tote with lid (Lowe’s)

1 – Hefty 66 quart plastic tote with lid (Lowe’s)

1 – 4’x8’ one-half inch EPS insulation board with one foil side (Home Depot & Lowes)

1 – six or seven inch length of 6-inch diameter drainage conduit (Home Depot*)

1 – roll of All-Weather duck (duct) tape – Regular duct tape may be used, but may be degraded by weather and UV light. (Home Depot)

*  Home Depot sells this online in ten foot lengths, with pick-up at your local store.  Since only about 6-7 inches are needed for each shelter, a ten foot length will build a lot of shelters!

Tools needed:

a tape measure or a T-square (a T-square works well to draw straight lines)

a black Sharpie pen

a heat-gun or a handheld hair dryer to heat and soften plastic before cutting the six inch doors.

a sharp box-cutter or other knife to cut six measured pieces from the EPS board, and the six-inch diameter doorways, aligned through both plastic totes.

a scissors to cut duck tape into useable lengths


The cat shelter consists of the Hefty tote placed inside the Rubbermaid tote, with a piece of half inch EPS insulation board between the inner and outer totes.  The shiny foil side of the insulation board faces inward – this reflects infrared and keeps the body heat from the cats inside the shelter, so they stay warmer.  The foil side of the insulation board may need to be wiped clean with a damp cloth or paper towels to remove excessive dust/dirt that has accumulated on the surface, before it is cut and installed.

Bedding can be straw, old towels, or anything that the cats can snuggle in to keep warmer.  Don’t use hay – it will absorb moisture and make the inside of the box damp and cold.  If using textiles as bedding, it should be monitored to ensure that it remains dry and clean.  Adult cats will virtually never soil the bedding.  Kittens, however, may not be wise enough to leave the box to take care of their business.  

Another option is an electric “K&H Lectro Soft Pet Heating Pad”.  These are available on Amazon in two sizes.  The smaller size works well for these cat shelters.  They are pressure activated, so they heat only when a pet is laying on them, and they only heat to the pet’s body temperature.  This helps the animal maintain its body temperature when it is especially cold outdoors, while drawing very little electricity, and with no risk of overheating.  The electrical cord is armored to prevent animals from chewing on it, and the cord can simply pass through the doorway opening.

Doorways should be placed on the end or off-center on a side (closer to one end and about 1/3 of the way up from the bottom).  In our experience, cats seem to like the door on the end, which enables them to cuddle up at opposite ends inside the shelter.  The plastic totes are not square.  They taper from top to bottom, so the insulation board for the sides and ends will need to be tapered, as well.  The inner tote is not as long as the outer tote.  If the door is on the end, there will be a void at the opposite end between the totes.  The insulation board should be cut to fit closely around the inner tote.  Some gaps may occur around the lid.  In a typical North Texas winter, these gaps are not a problem.  


  • Cut a six or seven inch length of drainage conduit.
  • Decide on the location for the doorway on the outside of the larger tote, and mark a six-inch diameter circle with a Sharpie, using the six-inch drainage conduit as a template to get the circle the right size.
  • Using a heat gun or hair dryer, heat the plastic and soften it to make it easier to cut the doorway.  Use a sharp boxcutter to cut the entry hole, following the Sharpie outline.  
  • After cutting the hole in the outer tote, put the bottom layer of insulation board in the outer tote.  Then put the inner tote inside and, using the Sharpie, trace around the hole in the outer tote to outline the place on the inner tote where the doorway will be cut.  (Be sure that the inner tote is sitting on the insulation board liner for the bottom to get the height right.)
  • Cut the inner tote doorway in the same manner as the outer tote doorway.
  • Put the insulation board piece for the doorway side of the totes in place between the inner and outer totes and trace where the hole for the door will be cut.
  • After cutting the entry hole in the insulation board, assemble the shelter, taping the corner edges of the insulation board sides together to make a tight fit over the inner liner.
  • Holding the inner and outer totes in place, insert the drainage conduit to create an entrance tunnel.  allow about one to two rings (about 1 to 1.5 inches of the conduit to extend inside to inner tote.
  • Cut 4 to 5 inch lengths of the tape to completely seal the conduit and the totes together.  Overlap the pieces of tape about a quarter inch to form a complete seal.  Repeat this on the inside of the inner tote. 
  • Completely tape all the way around the doorway to hold the two totes together and to keep moisture out of the space between the totes.
  • Tape all the way around both the inner and outer ends of the conduit to protect the cats from any sharp edges around the door openings.
  • Place the lid on the inner tote, cover it with the top piece of insulation board, and put the lid on the outer tote to complete the shelter.

Placing the shelter:

Depending on how skittish the cats are, keeping your shelter relatively close to a backdoor is a good idea.  It makes it easier to monitor use, and also discourages other critters from becoming squatters in your cat shelter.  Wherever you put it, be sure that it isn’t in the path of running water during a rainstorm.  Sitting it up on bricks or 2x4s to raise it up and protect it from rain, ice, or snow accumulation is a good idea.  Also, position it so that the entry isn’t facing north or west, to keep out the prevailing winter winds.  While we’ve never had a problem with wind moving our shelters, putting a couple of bricks or other weights on top might be a good idea.  We also stack these shelters two high, with a small wooden “porch” just below the height of the entrance to the top shelter, to make it easy for the cats to get in and out.