My lower toilet has been bubbling when the washing machine goes through it's drain cycle. The washer machine itself seems to have a very small leak from the washer when draining, and suds often comeback up from the drain hose pipe. The bathtub upstairs is also draining very slowly, no issues with the upstairs toilet. According to what I've found online, I likely have a blockage in either the roof vent pipe or further downstream, like between my downstairs toilet and where we connect to the sewer system. Seems like an easy DIY job to go on the roof and have a look down the pipe and remove whatever may be in there, (a bird maybe?) there are no trees around. Some of the information was saying do not try to remove anything yourself, but it seems like a (possibly) simple job to extract from the roof vent if that is my problem. If there is nothing there, I would like turn to a plumber, assuming the blockage is in a not to easy to access area. Any thoughts? Anything I could possibly screw up in the removal processes via the roof vent?