How To Make a Waterproof DIY Doghouse

This outdoor DIY Doghouse blog was written by a paid contributor. All photos were taken by Flex Seal Studios.

A DIY doghouse can provide a cozy spot for your pup while they spend time outdoors. Whether you’re planning on building a doghouse from scratch or already have one in your yard, this blog will show you how to create a waterproof oasis for your pet that can stand up to the elements.

Read on to learn how to make a doghouse of your own and how Flex Seal Products can help seal out water to add extra protection from various weather conditions.

Get supplies for this project now at Lowe's.


● Measuring tape

● Circular saw

● Jigsaw

● Compass

● Drill

● Phillips head bit

● ½” drill bit

● Metal snips

● Orbital sander

● Paint roller and tray

● Painter’s tape


● 1, 1x4x12’ cedar board

● 4, 2x4x8” pine boards

● 4, 2x2x8’ pine boards

● 1, 4’x8’ 1/2” panel board

● 1, 4’x8’ sheet of galvanized steel

● 1 Flex Seal can, clear

● 1 Flex Seal Liquid, black

● 3” exterior deck screws

● 1-5/8” exterior deck screws

● Roofing nails


1. Build Doghouse Base

Note: Use caution when working with power tools and always follow manufacturer’s instructions.

First, you’ll need to build a base to form the floor of your doghouse. Using cedar for a DIY outdoor doghouse is an excellent choice as it will help prevent decay and resist bacterial and fungal growth.

Cut the 2x4 cedar board using your circular saw and assemble it with wood screws to form a square base. Top the base with a piece of ½” panel board sized to match, using wood screws to secure the panel to the cedar frame.

You’ll also need to build a second cedar base to create the porch of your doghouse. Cut and assemble the frame to form a rectangular base and secure a piece of ½” panel to the top.

2. Frame Doghouse Walls

Next, use the pine 2x4 boards to frame the four walls of your doghouse.

The sides should be identical in design. Once each wall is assembled, you can also cut pieces of the paneling to attach to the frame.

Note: The paneling should be an exact match along the top of the wall and down the sides but will extend several inches below the bottom of the frame to overlap the cedar base. This helps prevent moisture from entering where the walls and base connect.

On the front and back frames, use the miter on your circular saw to cut supporting pieces to extend off the top of the frame and support the roofline. Then, attach the walls to the cedar base.

Flexpert Tip: When you cut the paneling for the entrance and back wall of the doghouse, make sure the angle of the roofline is identically cut. You can stack the paneling and use your circular saw to make the roofline cuts simultaneously.

Attach the back panel of the doghouse but refrain from attaching the front panel just yet.

3. Create Passthrough for Doghouse

Use your jigsaw to cut a passthrough through the paneling that will attach to the front of your doghouse. Using a compass makes it possible to sketch the top archway for your entrance and is more accurate than free handing the curve.

Attach the paneling to the wall frame for the front of the doghouse and connect the front using additional exterior deck screws.

At this point, your foundation and four walls should be connected and secure.

4. Create Porch Overhang

Use a circular saw to cut a porch framework to support the roof overhang. The porch overhang will be lightweight, so using a 2x2 framework is adequate. Two vertical posts will attach to the porch from the underside of the floor panel, and a rectangular frame will be assembled and secured over the entryway using exterior screws.

Flexpert Tip: It’s easiest to attach this overhang before putting the galvanized roofing panels in place.

5. Make Doghouse Roof

Now you’re ready for the roofing! Trim galvanized steel pieces for your roofline and attach each panel to the wooden frame using roofing nails. You should also cut a 2” wide piece of galvanized steel to overlap where the two panels meet at the peak of the roofline. This ridge cap will prevent rainwater from entering through the small gap and help direct water down the roof. Use additional roofing nails to secure the ridge cap.

Trim a smaller piece of galvanized steel and use roofing nails to attach the porch overhang panel.

Flexpert Tip: Galvanized steel can have sharp edges, so consider using an orbital sander to smooth and round off the edges of your DIY doghouse. This is especially important for the piece of galvanized steel that overhangs the entryway.

6. Seal Roof With Flex Seal Liquid

Now that you’ve constructed your DIY doghouse, it’s time to protect it with Flex Seal Liquid! Applying Flex Seal Liquid to the roof will help weatherize and seal out moisture that could enter through the roofing nail holes.

For this doghouse DIY project, we went with black Liquid to add contrast to the roof. If you’re looking for a different color option, keep in mind that Flex Seal Liquid is also available in white, gray, or clear.

Flexpert Tip: It’s always best to apply Flex Seal products in a well-ventilated area while wearing protective gear such as gloves and eyewear. Also, consider the weather forecast and plan to use products when rain isn’t a threat.

To prepare the roof for the extra sealant, use a clean microfiber cloth to remove any sawdust. Then, apply painter’s tape to the edges of the roofline to prevent the Flex Seal Liquid from adhering to the natural wood paneling. Next, fill a paint tray with Flex Seal Liquid to reduce the time you have to keep your can of Flex Seal Liquid open.

Flexpert Tip: Whether you use a paint roller or a brush, applying Flex Seal Liquid in long, even strokes is always recommended.

Once you’ve applied your first coat of Flex Seal Liquid, it’s time to let it dry. Allow 24 hours of dry time before applying additional coats and 48 hours for Flex Seal Liquid to dry completely. Depending on temperature and humidity, dry times may vary.

Note: Check out our “How to Use Flex Seal Liquid” blog for tips on proper application, storage, and more.

7. Seal Wood Panels With Flex Seal Clear

Lastly, you’ll weatherize the wood paneling on your structure with Flex Seal Clear.

Shake the Flex Seal can vigorously and spray in a sweeping motion, 8- to-12 inches away. Focus on visible screw holes and gaps where the paneling overlaps, and then address the larger surface area for best results.

Flexpert Tip: Let the first coat dry for 24 hours before applying the next coat and allow 48 hours for Flex Seal to fully cure. We recommend allowing the doghouse to fully cure before having your pet occupy the space.

Now you have a waterproof, DIY doghouse that every dog in the neighborhood will envy. Such is the power of Flex Seal.

We’d love to see your DIY doghouse ideas, so be sure to share them, and share with us on social using the hashtag #FlexDIY!

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