All, thanks in advance for the help. I’d like to add a utility sink near my washer. Currently there is one standpipe, shown in the picture and it does not vent through the roof, also no trap. Is it a big deal to drain both a sink and washer into the pipe? I planned to expand left [pic] for the washer and add draining for the sink to the right. Rough sketch over actual pic attached. any issues with this Approach, also should I add AAV to the top of the pipe since it doesn’t vent outside?