A major risk during the renovation of historic buildings is fire. Historic buildings often have dry, older timber, and heat from tools can ignite the wood. In particular, soldering has serious risks. Soldering sheet metal can ignite adjacent wood. Sometimes, unknown to the construction crews, there can be wood smoldering for hours underneath a metal roof.
Electrical sources can also present risks, like overloaded circuits or overheating tool motors. Today, battery powered tools can ignite, as many have lithium batteries.