My washer drain and sink drain are clogged very badly, I've read the questions and answers to this problem and I'm sorry for sounding so stupid but what is a roof vent. My house is on a slab, no basement. I see that the tall drain pipe for the washer empties into a larger roundish section with a hexegon type bolt top and then I have no idea where it goes. I to have tried to snake it out from the drain pipe. But I got nothing. Not sure if it even got past where it was supposed to.

Well there are 2 type of roof vents.. but I'm guessing you are asking about the one fore plumbing.

It is a long pipe that goes up and out the roof. It allows (I think) back pressure to escape.

Example:
Where it says vent stack.
http://www.terrylove.com/images/dwv_b2.jpg

My washer drain and sink drain are clogged very badly, I've read the questions and answers to this problem and I'm sorry for sounding so stupid but what is a roof vent. My house is on a slab, no basement. I see that the tall drain pipe for the washer empties into a larger roundish section with a hexegon type bolt top and then I have no idea where it goes. I to have tried to snake it out from the drain pipe. But I got nothing. Not sure if it even got past where it was supposed to.

A vent relieves the suction caused in the system by liquid that's draining into it. If the vent's clogged it slows the draining action down and that can cause blockages. All our homes are on on slabs in my area so I understand your layout. That larger roundish section with a hexegon type bolt top is called a "clean out or inspection tee" and it connects into a branch that also services the kitchen sink so if you have a blockge inn the branch it affects both fixtures.
I to have tried to snake it out from the drain pipe. But I got nothing. Not sure if it even got past where it was supposed to
If, by drain pipe you are referring to the washer vent pipe you didb't put out enough snake to reach the clog. Go back and snake from the washer roof vent. Put out enough snake to reach the base and 20 feet more. If you mean the washer stand pipe you're snaking from the wrong place. Let me know how you make out. Good luck, Tom

First of all thank you so much for taking the time to help me.
Now I checked our piping and there is no way for me to get to the "roof vent" our piping goes up into a very small crawl space that I have never ever been in before and never really want to.
Is there any way I can snake from that "clean out or inspection tee"? Would that work? I know that I cannot snake from the roof vent.

Yes you can snake it from the clean out, but if your vent is clogged up stream then it will not help you, you need to snake it from the top (roof vent) as Tom have stated, good luck.

John

If your washer connects upstream from the cleanout tee, (see image) then I would say the blockage's downstream from the tee and can be snaked from there. Remove the cover from the clean-out tee and send at least 20 feet of snake down the branch to be sure you get to the main. Good luck, Ton