Leatherman Slab Started

Today the first portion of the concrete floor slab for Leatherman’s new warehouse was cast. Work started before sunrise so that the finish troweling could be accomplished before dark. The new warehouse is located near Portland International airport, across the street from their manufacturing plant. Stratus Developers is managing the project on behalf of the Leatherman family and company management.

The action picture shows the screed machine smoothing the concrete to an exact level based on laser technology. This machine revolutionized large slab screeding that used to be accomplished by pulling a straight edge spanning across the top of the forms. It dramatically increases productivity so that larger and larger slabs can be cast in a single day. And the floor flatness and floor levelness are much more precise. That’s important especially in modern warehouses in which forklifts and automated retrieval machines will be placing and picking items to and from racks high up off the floor.

Note the phrase placing concrete is intentionally used versus pouring concrete. Ideally concrete is placed with a low slump, stiff and not very runny. Lower moisture concrete in plastic concrete reduces the amount of shrinkage as the concrete cures, in turn reducing the shrinkage cracks as the concrete cures. Some cracking is unavoidable with hairline width cracks normal and typically without negative consequence. Cracking is also controlled by saw cutting the concrete slab crack control joints just as soon as it has cured to be stiff enough to support a person with a wheel mounted concrete saw. Often large slabs are cut into 20 to 25 foot sections.

Two more increments of slab will be cast in the first ten days of September. Then the following step will be to form up the concrete wall panels on top of the slab. Completion of the building is scheduled for summer 2022.