Building Masonry Cookstoves
Determine the location,
making sure there is no obstruction for the
stovepipe. The family must be involved with this decision. Level the
ground on which the stove will be built on. After being sick from
breathing too much smoke, I always insist that they move their
cooking fire outside while we are working inside.
Ideally members of the family will carry the materials and water, do
the mixing, sift the gravel, fill the bottom 2/3 of the stove, and even
cut and lay blocks if they have those skills. The more they are
involved with building the stove the better. Mix a large batch of 1 part
Portland to three parts sifted gravel and lay the first course of blocks
on a bed of mortar. Wet each block first.
Carefully lay the next course beginning sure that all joints are
Fill the center area with fill, ideally pumice but if not available, dirt.
Lay the top course of blocks leaving an opening in the front for the
door. Fill the block cavities with dry wood ashes.
Mortar in the door and lay the bricks for the walls of the firebox. The
top of the bricks should end up about 1˝ inches higher than the
concrete blocks. Soak each brick first in salt water. Use a mix of 1
Portland, one lime, to two sand.
Lay the brick floor dry; wood ashes will fill any gaps between the
Mortar in the door. With a couple of extra bricks and some wood or
folded paper shims, place a piece of board (which will later be
removed) to support the concrete over the doorway.
Set the Plancha (stovetop) in place on top of the brick walls. Then mix
up a batch of 1 Portland to 3 sifted gravel to pour the top. Be sure to
imbed four pieces of rebar over the door opening. The 3 sections of
stovepipe need to be installed at this time. The bottom pipe goes
through the concrete top, flanged at the bottom and supported by
bricks. A hole needs to be cut through the roof directly above.
Sometimes we have found that the roofing is not nailed down, if this
is the case then it needs to be now. Use a plumb bob to locate the hole
through the steel roof. I have found a leatherman tool extremely useful
for punching a hole through the steel roofing and making small holes
through the pipe for wiring the sombrero on. The sombrero (rain cap)
needs to be wired on. The concrete top needs to be worked to a
smooth finish. Central American masons will sprinkle pure Portland
onto the top, making a paste that they work smooth. They use their
bare hands, which are scarred from the caustic cement. If you value
your hands, use gloves.
With a mix of 1 lime to 2 fine sand, parge the outside walls. The
proper mix will stick to the block walls when buttered on with a steel
trowel. Use a wood float to obtain a smooth finish. This step and
obtaining a smooth finish on the top, takes considerable skill but only
with practice can you learn.
At this point you can congratulate yourself and the family members
whom have been helping. Their living conditions have been
dramatically improved. It is important that they know not to use the
new stove for two weeks to let the cement cure. It is helpful if they
keep the concrete top wet for the next two days by sprinkling it with
water whenever it looks dry. With a nail you can hang the lid lifter