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DIY Air-Conditioned Dog House: Installing a Drop Ceiling and Insulation

The finished dog house.

The finished dog house.

Designing an Air-Conditioned Dog House

There were two issues that required some thought. First, since I planned to only temporarily use the air conditioner, I wanted to run an extension cord through the ceiling so as not to have to try to get it down through a wall.

I did not want to drill through the siding at a low part of a wall, because moisture could get in. I drilled a hole up high (close to the rear roof) using a hole saw. I already had the hole saw from prior projects where I used it to cut holes for door knobs.

The ceiling support along the back wall was selected to be wider than the others so that a large enough hole could be drilled to permit the plug of the extension cord to go through. I did not use the hole saw through the soft wood of the ceiling support. I used a large wood bit and widened the hole.

Finding the Right Insulation

The other issue was that I had to figure out how to get a single piece of polystyrene insulation to go through an opening that was smaller than the piece itself. There is room underneath the rafters to tilt the piece sideways and work it into place, but only if one end of the horizontal support is left off until the ceiling piece is in place.

That last piece needed to be wider, both for drilling the hole for the extension cord, but also to give me an extra inch or so to allow me to shift the piece away from the horizontal support on the other end, by the door. Then I needed to be able to shift the piece forward to avoid having an air gap.

Because the last support was so wide, I couldn't just insert screws horizontally into the studs like I did for the narrower supports. I pre-attached to it another piece of wood of the same length but oriented so as to make an L shape. The piece that was at right angles to the support piece was then screwed into the studs.

Installing the Insulation

I used Lowe's part number 41505, "1.5 Inx4x8 Expanded Polystyrene" for insulation. This material should also help to divert or trap moisture leaking in until it evaporates (we get about 4 inches of rain per year). I made the cuts with a linoleum cutting blade included with the "Kobalt 28 piece All Purpose Knife kit", Lowe's part number 12809. This was the best way I found for cutting this material. It was still messy, but the Shop-Vac (also purchased at Lowe's) took care of the "crumbs".

Since the studs are not always perfectly straight, I would measure the gaps at top and bottom, and tried to cut the pieces of insulation so that they would fit snugly. Sometimes I had to cut a little extra when my initial cut didn't want to squeeze in. Sometimes I had to drive a couple of nails into the studs when the insulation was not fitting snugly enough. See the photos below.

Some of the insulation came with a shiny metallic coating on one side, but some did not. I picked one that did to use for the ceiling. I thought it looked better.

Installing the Drop Ceiling

As described above under "Design Considerations", after cutting the ceiling piece to size, the trick was to have one end of the ceiling support be extra wide and pre-attached to another piece of wood so that it could be screwed into place after the ceiling was in place. You can see the ceiling support in some of the photos, above.

For the ceiling support on the two long walls and the short wall with the door, I used Lowe's part number 4511, 1" x 2" x 8' Premium Furring strips. I bought four. For the other short wall, I used Lowe's part number 4510, 1" x 4" x 8' Premium Furring Strips. I bought eight because they were intended to be used for the exterior trim. I used a leftover piece for the ceiling support.

To attach the furring strips to the studs, I used the same exterior screws as for the exterior trim, Lowe's part number 323893, "1 - 1/4 x 8 x 8 PGP EXT SCR STARD". I attached the strips with the wider dimension extending out from the wall. I may have drilled small starter holes, at least for the first couple of screws in each strip.

For the 1 x 4 strip, I attached a 1 x 2 strip of the same length to form an "L" shape, using the same screws. Then that assembly was attached to the wall studs through the narrower dimension of the 1 x 2 strip.

Installing Outside Corner Trim

The outside corners are trimmed with the same 1 x 4 furring described above in the section "Installing the Drop Ceiling", and also used on the crown of the roof. I used short 1 x 4 cuttings from installing the roof trim to lay out and mark each corner, in terms of how the two pieces would fit together at each corner.

One piece extends out from the wall it is attached to just far enough that its edge will be flush with the other piece that will butt up against it. It is easier to mark top and bottom positions using the cuttings than to lay the full-length trim pieces together, and mark that. Of course, if you have help, your assistant could hold the pieces in place while you install the first screws, and you could skip the marking step.

The two corner pieces are each fastened to the wall with one column of screws, and are fastened to each other by another column with each screw being driven in from the overlapping piece into the overlapped piece. I used the 1 1/4 inch exterior screws described above, Lowe's part number 323893.

Paneling the Inside

The main reason for paneling the inside walls is to prevent the dogs from tearing into the insulation. I picked Lowe's part number 12549, 5.0 mm utility plywood. It cost $11.75 per 4' x 8' sheet in 2012, and I bought five sheets to panel four walls. Each side wall used one and a half sheets, and one sheet was used for each end wall.

I used the 1 1/4 inch exterior screws described above, Lowe's part number 323893. The photos above should be self-explanatory. One design mistake I made was in framing the interior corners.

After installing the first piece of paneling on a side wall, I noticed the mistake. I could have taken the piece off and installed some more 2 x 3 pieces to fix the corners, but I was in a hurry to finish and jury-rigged a quick solution that kept the upper and lower panels connected to a wooden block so they would at least be flush with each other.

I figured it's just a dog house, and if it weren't for the dogs, there wouldn't even be paneling at all, and it would just be a storage shed. But you can learn from my mistake.

The last two photos in the last set of thumbnails are of the hole in the exterior siding through which the extension cord was passed. The hole was drilled out using a hole saw. I still haven't got the cut-out siding out of the hole saw, though. But I don't think I'll ever need it again, because any new interior doors for our house will be bought with the doorknob holes already cut out.

Installing a Shelf

The two shelf supports were cut off the end of the shelf board. I forgot to write down the Lowe's part number, but the bar code is visible in one of the photos. I zoomed in on the photo and confirmed the board dimensions are 1" x 10" x 4'.

It looks like the width of the shelf was 42 and 13/16 inches, but I probably just marked the cut straight off of the extensible handle (see photos above) laid on top of the board. Then I marked another cut about halfway to the end. Each support is about 2 1/2 inches wide.

I left about a two inch gap between the shelf and the back wall. This allows the AC cord to pass behind the shelf, saved me from having to drill a hole through the shelf, and allows me to center a larger box on the shelf (say 14 inches deep instead of 10).

I used the same 1 1/4 inch exterior screws as for the other interior work, a total of four on each side. The photos show the screw placement for the supports. A pair of screws were also driven down through each side of the shelf into the corresponding support.

Balancing Temperature in Summer and Winter

For a number of months, the dog house served its purpose well. The dogs were able to go in and stay a bit cooler. But the dogs were not exactly in the "lap of luxury" because even with the air conditioner running in the heat of the day, it was still warm inside. But just dropping the temperature from 110 degrees F to 95 makes a huge difference to either man or dog. And in the morning and evening, it did get really cool inside.

When it got cold, I tried putting a space heater on the shelf to see how effective that would be. I do not recommend doing that at all unless you have an electrician do a proper installation of a power outlet inside the dog house. Maybe not even then.

The heater hardly seemed to make any difference to the temperature inside, but when I unplugged it from the heavy-duty extension cord, the plug was very hot! Heaters draw a lot of current, and an extension cord changes the electrical characteristics of the situation in a dangerous way.

I hesitate to even mention that I actually tried this (I believe the heater instructions warn against it), because I don't want to be responsible for planting the idea in anyone's head. But the idea is such a natural next step that I decided to go ahead and mention it, but with a clear admonition to never, ever connect a space heater through an extension cord.


Maggie went to Japan, and our dogs are now allowed back into the den/kitchen section of our house. The new love seat has been moved into another room to which the dogs do not have unsupervised access. The dog house is now functioning as a storage shed.

The project was worthwhile because I enjoyed designing and building it, planned to write about the project online, and have enjoyed writing about it. It is a unique building, and although it is theoretically portable, I'm not sure I want to go to the trouble of taking it apart and putting it back together, or paying for a crane to lift it out of the back yard.

My hope is that people will find this series of articles useful in some way for what they are doing, even though few, if any, will be inclined to build anything quite like this.

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

© 2014 Dale Tinklepaugh


Dale Tinklepaugh (author) from Salem, Virginia on March 22, 2015:

Thanks, FlourishAnyway. I figured it would really be awesome if I added a TV, a recliner and a mini-fridge. Then I could call it a "dog cave", and whenever I end up "in the doghouse" I could do it in style. But I don't think the recliner would quite fit.

FlourishAnyway from USA on March 22, 2015:

Amazing. That is one lucky dog! What an awesome dog house.

Dale Tinklepaugh (author) from Salem, Virginia on March 22, 2015:

mySuccess8, thank you for your kind words. It is my hope that others may benefit from my experience, and perhaps be encouraged to attempt something constructive themselves.

lions44, thank you for your kind words as well. I just checked my Hub statistics after church this morning and thought there must be a bug! So I checked my email and saw two comment notices and a Hub of the Day notification. Thank you for your support.

CJ Kelly from the PNW on March 22, 2015:

Great article. Your dogs are treated well. Voted up and shared.

mySuccess8 on March 22, 2015:

The finished dog house looks amazing, and your effort involved in constructing makes it so worthwhile. Though it was built for temporary use, you have shared various useful technical lessons learned for designing and installing future similar projects, including to never connect a space heater through an extension cord. Congrats on Hub of the Day!