Graphic #1 Example ferrocement armature

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Cold joints

Wall cold joints are usually vertical and require attention at the end of each day. Here you will need to keep the nozzle of mechanically pumped application precise so no mess is made where tomorrow's work will begin. This difficulty is precisely why it is wise to consider larger crews and hand application for walls; the cost is equal unless labor is unavailable or unusually expensive, supervision and clean-up are both much less intense. Horizontal cold joint have been used successfully for ferrocement pillars with no seperation cracks visible after 30 years, in an earthquake prone region.

Surface finish is represented as darkest grey, it is held back from the cold joint 2 -6 inches, which is five to fifteen centimeters, sometimes less and sometimes more. The surface finish is about 1/2 - 3/4 centimeter thick (3/16 - 3/8" ), it is totally complete and ready for color.

A longer wood or sponge trowel is positioned half on hard yesterday's work and half on new today's work, use a horizontal to slightly circular motion across vertical joints to make the cold joint disappear. Larger grains can be an irritation because they roll on the hard underneath layer, wipe them away with a rapid motion using a clean sponge. The completed cold joint is fresh plaster extending 2 - 6 inches onto yesterdays work, which has cured 1 day out of 28 and will bond to the new.

Be sure no visible, free, shiny excess water is present to create a skim barrier which will separate new from old. If a high spot protrudes from fresh plaster, use a stone mason's chisle to carve it off.