In the process of a job-site inspection, we noticed than many sill rails were bent at the ends where the screws connect the rails to the mullions. (Nearly all rails on the two most recently completed floors!) Some were bent so bad the paint was cracking. After about 10 seconds of analysis it we suspected that the units were fitting tight and workers were practicing their high jump landings on the sill rails in order to set the units. UPDATE: It wasn't high jumping. The culprit was found on our next inspection. (Click here to see that True Story.)

When asked why his workers were jumping up and down on the unit sill rails to set the units, the contractor actually responded "If you would look at my method statement, you'll see we were supposed to be using hydraulic jacks on the anchors to set the units." After repeating the question, I got the classic "The jacks were taking too long to position, so we stopped using them." "Hum", I wondered "how much it is going to cost to fix or replace several hundred units with major league bent sill rails?"

This contractor decided to save a few peanuts by ordering slightly shorter screws from what the drawings called for. The new shorter screws (the self-drilling type) were not always long enough to get any threads in the steel tube. "But that drill point goes in pretty darn far."

Fortunately for the curtain wall contractor, this only occurred when the condition was shimmed more than about 10 mm. Fortunately for the building's owner, ALT caught them. Fortunately for the screw supplier, they got to sell a lot more screws.