Four Tips for Mixing and Pumping Field-Mixed Stucco Basecoats
When preparing to pump stucco basecoats, the right mix can make all the difference. Fiber reinforced cement basecoat consists of an 80 pound (lb.) bag of concentrated cement mixed with 200-240 lbs. of washed sand certified to American Society for Testing and Materials (ASTM) standard C897 or C144, and potable water.
Many manufacturers offer proprietary “pump grade” mixes which contain a greater proportion of lime, a workability agent added to mortar mixes. These proprietary mixes are ideal for providing better pumpability and better product on the wall, and are highly recommended if available. Manufacturers do not always have pump grade mixes available, though, so field mixes are sometimes needed. To help ensure smooth pumping and avoid pack-outs, follow these guidelines to prepare the mix.