Ferrocement Concrete tank

From Eric Friesen’s facebook page. Project is in Nicaragua. Thank you Eric!

The system in a nutshell, spacers holding the reinforcing —- not attached to forms, — filling in the base of the wall, forms are raised on bricks to allow spillage for base beyond the wall, boots are a good way to move mud at this stage!

A few short screws from the outside hold the plywood overlap, the rope with a come-along snugs up the final overlap. Notice the spillage under the wall, the base is extended even further. Approximate steps…

  1. First excavate hole, pour the floor slab, leaving rebar around perimeter bent up to tie into the wall mesh — 1/4″ bar mesh covered with chicken wire.
  2. Attach vertical 1″ x 4″ spacers to outside of rebar, about 24″ O.C. leaving bottom¬† 2″ to 3″ open. This allows some concrete spillage underneath, to form a stronger base.¬† Attach spacers with a single nail or screw so it can be removed after concrete has started to set.
  3. 1/4″ plywood tank forms (simple overlap) with 1″x4″ spacer, cinch with a rope and come-along, raise forms 2 to 3″ from bottom for stronger base.
  4. “mudding” the tank, a 2″ base was poured before the mold unit c/w wire was placed in the hole. — best to leave enough outside room to parge the outside of the tank later!
  5. More mud, second coat, after a lunch break for the initial layer to set a bit
  6. “Dashing” the mud layers leaves a porous outside surface, which received two coats of fines (parged) with a sponge float as a sealer

The system in a nutshell, spacers holding the reinforcing —- not attached to forms, — filling in the base of the wall, forms are raised on bricks to allow spillage for base beyond the wall, boots are a good way to move mud at this stage!

A few short screws from the outside hold the overlap, the rope with a come-along snugs up the final overlap, notice the spillage under the wall, the base is extended even further

EDITED 10/3/12 TO ADD LINK TO ANOTHER METHOD. It does without the plywood backing, but appears to be stronger reinforcement / chicken wire…

This entry was posted in food and tagged , , , . Bookmark the permalink.

Leave a Reply