Things You'll Need
Instructions
Selecting a location
Locate a flat site with hard-packed snow. There should be at least three feet of hard-packed snow at this point. You can also select a site that is on a hillside and excavate the site.
Mark the circle that will be the base of the igloo with sticks.
Tramp on the snow for a number of minutes to insure that you will have hard-packed snow. After you have tramped, let the snow refreeze over a matter of half an hour. This refreezing will result in very strong ice blocks.
Excavate the circle area by beginning to cut your snow blocks, so that your base is under the snow level.
Building the igloo
Cut snow blocks with your snow saw. They should be six inches to 12 inches in thickness. Be sure that the blocks are hard, but not so big and heavy that they tire you during construction.
Place the initial ring of snow blocks around your excavated circular base. Place them tightly side by side, but at a slight angle inward to begin the angle of the dome.
Place the successive layers of snow blocks on top of the base layer. These blocks will slightly decrease in height as you go along. Overlap joints on each layer to increase strength. Be sure the joints are smooth and fit tightly.
Build along in a spiral fashion until you have reached the top of the dome. Cut the capstone (final block) to fit the gap as closely as you can.
Finish construction
Fill in all cracks with snow and pack it tightly. Smooth with your hand.
Cut ventilation holes in the sides of the igloo to prevent suffocation.
Dig an entrance hole from the excavated center to the outside of the igloo.
Shovel snow onto the outside of the igloo, being careful not to cover your ventilation holes. This will add to the strength of the structure.