We live in upstate NY, which means we're accustomed to cold and snowy winters. This winter, however, has been unlike any in recent memory. We've had over a month where nearly every day brought sub-zero temperatures. It's enough to make you start to lose your mind!
A few weeks ago, I took a look at the extended forecast and saw no end in sight. This got me thinking about an internet picture of an ice block igloo that someone had made using empty milk cartons for molds . They had colored the water of each block, resulting in a perfect little domed ice-house which was especially beautiful when lit up at night. From the moment I saw that picture I knew we had to make one, and we now had the weather to make it possible.
After about a week of ice-block production and igloo construction, we accomplished our goal. The process was remarkably easy - albeit a bit tedious and time consuming. The end result, however, exceeded all of our expectations.
Step 1: Gather Your Materials
* Food coloring
* 25 plastic shoe box containers from Walmart. These run about ~$1 and work perfect. (I considered milk cartons, but it would take us months to drink that milk and orange juice).
* Garden pump sprayer and/or sprinkler can
* Plastic tub (for mixing show and water)
* Sustained temperatures of below 10 degrees. This allows for about 2 batches of ice blocks per day.
Step 2: Making the Ice Blocks
This is by far the most time consuming step. I had purchased 25 of the plastic 'shoe box' containers at Walmart. If I had more then it would have taken less time, but I didn't feel like spending any more money until I saw how this was going to work.
Unfortunately my exterior faucet freezes each winter. This necessitated hauling 5 gallon pails of water from my kitchen sink out to the plastic containers in my back yard. It takes about 15 gallons to fill all 25 containers. Food coloring was added with the water and mixed well. I used 4 colors along with about 20% uncolored blocks. About 150 blocks were made in total, and we used nearly all of them.
On my first batch, I filled the containers all the way to the top. The water, of course, expanded when it froze and grew up out of the container. With the ice extending over the top, it became difficult to separate the ice from the container and I ended up losing some containers to breakage.
I filled the subsequent batches about 2/3 full. This allowed the ice to grow, but not completely come up to the top. I was able to push each sidewall slightly away from the ice. Upon flipping it over, the ice then slipped right out.
Step 3: Laying the First Row
If your igloo is to have even and straight rows, it needs to be built on a level surface. My back yard is not quite level, so I built a small 8" high by 1' tall 'footer' out of wet snow. This footer was made to a diameter of about 6'. To achieve a reasonably round circle, I first scribed a guide line in the snow with a crude compass made from a broom stick. I held the stick at one end and had my daughter rotate the other end around me, scraping a line in the snow at the end of the stick as she moved.
After building up the footer, I took an 8' 2x4 and laid it across the circle at various points. Using a 3' level on top of the 2x4, I was able to see where the high spots were and scrape them down.
I then started laying the first row, one block at a time. I wet the snow under each block to help it freeze together to form a quick and strong bond. The blocks sidewalls are tapered to match the plastic shoe box molds. This works to our advantage as when subsequent blocks are placed on top, they will start to form the dome shape on their own.
Snow was jammed between each block and sprayed with the garden sprayer to seal the gaps.
Step 4: Making the Mortar
Since the temperature was below 10 degrees when we made the igloo, naturally wet snow was unavailable. As a result, water had to be mixed with the dry, powdery snow. We used two methods to do this:
Method 1: Garden Sprayer
This is the method I started with. I would place the dry snow along the already laid blocks and then spray it with water. This worked well for the horizontal surfaces, but it was difficult to use on the vertical seams between each block.
Method 2: Sprinkling Can and Mixing Container
I soon moved on to making my own 'slush' in a plastic bin. I simply filled the bin with snow, watered it down, and mixed it up with a trowel. The slush could then be applied like mortar, both on the horizontal and vertical surfaces, and on the inside and outside surfaces to fill in any gaps.
Step 5: Add the Remaining Rows
As previously mentioned, the tapered edges of the shoe box containers work very well to facilitate the curvature of the dome. After adding each row, I would step back from the igloo to see if it was still level and true. I ended up removing and relaying a few sections to correct some anomalies that couldn't be seen without perspective.
As the blocks transition to a vertical orientation in the top three or four rows, we found it important to have two people. One person would place the mortar and then position the block. The second person would then fill the gaps on the outer surface with mortar. These gaps get bigger as you get closer to the top so it is important to fill them. Since the temperatures were so cold, the slush froze up almost immediately - which worked to our advantage at this stage of the build.
To reduce the size of some gaps, and to fill some of the irregular openings near the top, we used a hatchet the shape the blocks. This worked extremely well. I feared that the blocks would just crack apart, but they the remained intact and were very easy to shape.
Step 6: Making the Entry Tunnel
We started with one column on each side of the opening. These were placed about a block's distance away from the igloo. I tested the width between the columns to make sure it would easily fit an adult.
The columns started to get unstable when they reached five blocks in height. At this point, we added the second column to connect them to the igloo. This stabilized the columns and allowed for the adding of the upper rows where were almost horizontal.
Step 7: Turning on the Lights!
With the igloo complete, we eagerly ran an extension cord to power the flood lights. A hole was poked through the footer for the cord so we didn't have to run it through the entry tunnel (I didn't want it visible in the pictures).
We were not disappointed when the lights were turned on. The igloo glowed colorfully just as we had intended.
In total, we spent about 30 hours on this project. The only thing left to do was spend the night in our little domed house. For some reason, my wife and children said they would disown me if I did - however, I'm not giving up! There are still a few more weeks until the spring thaw!