Roll roofing
 

We layed roll roofing on a builing on my farm. A masive wind storm has ripped it. I need to know how to fix it. Do I put the repair piece under the main part on the house to seal it? We also were going to put tar along the ripped sides for a seal so we get no leaks will this do the job?

Yup
 

Basically you need to be layered to shed the water. If it looks like water will penetrate and area by just flowing downhill , layer it from the bottom up. Tar will help to keep it down, the less penetrations the better.
Pics would help , but it sounds like it is a straight forward fix.
I would install a new piece where the tear is and overlap all sides at least a foot where you have a vertical seam. And tar the edge .
Good luck:)
Don't tuck your raincoat in your pants and think some sealant will keep it out.

Thank you for your help.