I have had solid waste back up into my tub from my toilet. This is obviously plumbed incorrectly. Is there a diagram showing how plumbing should be done. Is there a way to block the toilet from the tub? Help!!

I am not so sure it is plumbed incorrectly but maybe you can attach some pics or a diagram. If your drain is plugged downstream of the tub and toilet the backup will come out at the lowest point, the tub. Don't try to block anything, rod rather than block. If you have no clean outs try rodding down the vent stack or pull the toilet if you have to.