A shortage of lumber is affecting the North American construction industry in what's usually its busiest time of the year.  Both big construction companies and smaller contractors are feeling the supply crunch, which began with the onset of COVID-19. The pandemic caused a big decrease in supply, as well as an increase in demand - likely spurred by homeowners opting to renovate while they're stuck at home.  Nova Scotia-based Rooftight Construction president Scott Smith told MSN that his company has been much busier than usual over the past few months, but a lumber ...