Updated at: 16-08-2022 - By: Jane Brody

Since a wooden birdhouse already has insulated walls, little work is required to winterize it so that the birds are protected from freezing temperatures.

Covering the air vents, which double as drainage holes on the floor, is a simple way to winterize a birdhouse on your own. The block of wood used to cover the hole should be raised slightly to ensure adequate drainage. Fill in large spaces with exterior-grade insulating foam that is out of reach, or cover the floor with wood chips.

insulated birdhouse

The birdhouse itself will already be winterized if you’ve placed it so as to attract a certain species of bird.

However, as long as the box is kept cool, it doesn’t hurt to take extra precautions to protect the birds that return to it night after night. Birdhouses are typically constructed from wood, so the thick walls should provide some insulation for the roosting birds.

Do not remove birdhouses from your property during the winter months; birds will utilize them as roosts. Instead, you can leave it as-is, cleaning away any old nesting material, and make it ready for the birds that will be using the box as a roost this fall and winter.

In order to prevent or drastically restrict the flow of cold air into a wooden box during the winter, it is necessary to cover up a section of the air vents.

That’s easy enough to achieve by simply placing a block of wood over the drains in the inner floor, however it will need to be raised so water can still flow through.

The snow on the birdhouse’s roof can act as insulation, but it should be removed or melted with grit or salt if it becomes too heavy for the structure.

If you want to keep roosting birds warm in the winter, positioning a bird house in your yard so that the entrance hole is protected from the direction of the prevailing wind is essential.

Cover up birdhouse base

To lessen the chill, you can plug the drainage and ventilation holes in your birdhouse. However, remember that any type of birdhouse can become flooded if there aren’t any drainage holes (or if there are, but you accidentally cover them up).

To begin, you will need a plank of wood that is the same size as the bottom of the birdhouse to hide the holes you made when you built it.

In doing so, it is possible to significantly lessen the amount of chilly air that is allowed to enter the box, protecting any birds that may be roosting inside from the elements.

Now, for reasons of safety, we must make sure the vent holes that function as drainage holes on the floor are not completely covered up, as a birdhouse, particularly in the weather, does risk flooding.

If you want to double the thickness of your floor without sacrificing ventilation, you can use a block of, say, half an inch thick plywood or cedar.

That way, you can use several extra wood planks to build up the floor, and then set the covering wood block on top to let some air circulate under the whole thing.

Close gaps in Insulating Foam Sealant

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Besides potentially covering the drainage/ventilation holes to reduce cold air flow, I can’t think of any other technique to winterize a birdhouse.

The roof overhang on either side of the birdhouse provides an opportunity to close off any excessively large openings in the upper part of the structure.

Air circulation is essential in a birdhouse, but in the winter we may cover it to protect the roosting birds from the elements.

Blocks of custom-sawn wood, or an outdoor-grade isolation foam, should be used to fill in the too-large spaces first.

Just so we’re clear, I want to stress that this material is not dangerous to humans but is lethal to birds if they are permitted to swallow it.

Use this outside graded isolation foam just on the interior birdhouse’s highest point, far from the roosting birds’ grasp.

There’s no need to worry about chicks or budgies getting sucked into the foam, but even adult birds can choke on tiny bits.

This outdoor insulation foam should be sprayed into extremely large cracks, such as those typically seen under a roof overhang; however, it should never be sprayed lower down.

Salt to melt snow buildup on roof

Since most common bird species only use birdhouses for sleeping during the winter, we don’t have to take as many precautions to safeguard their nests and young then as we do in the spring.

Perhaps the process of gritting our backyard garden is comparable to that of winterizing a birdhouse in sub-zero temperatures.

Maybe you could see if you could get your hands on a bucket of ice and snow melting grit to put on top of the birdhouse.

We can’t rely on bushes or trees to provide cover because the area around any birdhouse would likely be open.

What the melting grit will do is potentially cause any buildup of snow to simply melt away.

Although it is not crucial, remember that if the birdhouse gets too much snow, the birds who are roosting inside could fall to the floor.

Likewise, you could simply sprinkle table salt over the top of your birdhouse, although this could potentially damage the wood. Don’t worry about it; just add another old plank of wood to the birdhouse, or maybe some aluminum foil to keep the elements out.

If you install a large plank of wood above a birdhouse on the roof, the cats won’t be able to reach the entrance hole, and falling snow or wind won’t be able to get into the home, either.

Layer interior with 2 inch wood chips

insulated birdhouse-3

Never take the simple route of tearing down the birdhouse in the winter to avoid the hassle of winterizing it.

During the spring and summer months, birds use birdhouses for nesting purposes, but once the nesting season is over, the same birds, or new newcomers, may utilize the birdhouse again to roost during the winter.

Line the bottom of the birdhouse with wood chips to keep the wild birds warm or at least comfortable.

Only wood chips, and nothing else, are permitted in a birdhouse, despite the fact that some bird species benefit from the added nesting material.

Wood chips, about 2 to 3 inches thick, can be used to line the bottom of the birdhouse, but this is optional.

A birdhouse’s value lies in the fact that it provides a safe haven for birds during the breeding season and also provides shelter throughout the harsh winter months.


There is nothing you need to do to prepare a birdhouse for the colder months of winter; all you need to do is remove any old nesting material and put it in a safe place.

We should not worry about unhatched eggs or young birds at this time of year since they will come to roost in your birdhouse to withstand the extreme cold.

It’s not too late to reinforce our birdhouses to keep the frigid air out.

We may do this by removing a piece of the drainage holes in the bottom of the birdhouse, which also serve as ventilation holes. Cover the vents in the inner floor by placing a slab of wood over them.

This block of wood needs to be slightly raised so that any water or moisture may still drain away.

There is a chance that roosting birds could be harmed if your birdhouse has really large, unobstructed openings, but we can seal them up to some degree or completely.

Foam insulation designed for outdoor use can seal cracks and keep the cold out.

One solution is to sprinkle snow-melting grit over the roof, but snow-covered birdhouses can keep a comfortable temperature year-round without any additional heating or cooling.

Similarly, covering the roof with aluminum before applying ordinary salt prevents the salt from deteriorating the wood.

Applying two or three inches of wood chips to the inside floor of the birdhouse might serve more as comfy bedding, but is not required.

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