My question is a contractor installed a vent pipe through te side wall joist it is a double joist. One joist then the one that sits on the sill or top of basement foundation. he cut all the wood out of the first joist with a sawzall to install the pipe and then looks like he drilled a 4" hole throgh the outer joist to put in the vent. Is this normal or did he damge my house structure. the first joist sisters up to anoher one on top of the steel beam that runs the length of my house.