I’ve done several suspended slabs and had a few concerns about the article “ Pouring a Structural Slab” (7/12). I noticed that none of the structural steel was primed or painted. Given the job’s proximity to water, I would assume that the more humid air would quickly rust the steel and that Massachusetts code would require the exposed steel to be painted. During temperature swings or humid weather, moisture in the air will quickly condense on the unpainted steel in the enclosed storage area and continuously drip onto the concrete floor, causing staining and wetting the owners’ belongings. At a minimum, the pans should have been painted with a rust-inhibiting primer and top-coated with enamel before they were set in place.
I was also surprised the builders used 6x6 mesh instead of a rebar grid. Because this is a structural suspended slab, a 12-by-12-inch grid of 1/2-inch rebar should have been used. Normally 6x6 mesh is used on slabs-on-grade, where it keeps the slab surfaces more or less in alignment if the slab cracks. But unless great care is taken to pull the...
to read the full article.