chewing while in garage, urinate in crate

Question
We are having a little bit of a problem with our Black Lab, he is a wonderful dog we resuced from the humane society. We tried to crate train him while we are away & (sometimes)he urnites & may have a bowel movement in the crate, my husband wanted him to have more room so we moved him to the garage while we are away - invested in a heater & everything. Now he chews on things that aren't his (coolers, tool holders, soda boxes) we have toys for him in there, chewy's all kinds of stuff, but we are at wits end and about to but a muzzle on him while we are away. He chewed our sons birthday toys that we had hidden on a low shelf in the garage. ARG! He also urintes on the garage door (which drives me nuts).

I would like to keep him in the house, but afraid he'll elivate himself and chew up everything. even if he's in the crate, but he will urinate in the one corner(we have a new house)we've tried leaving him free for short periods (4 hours)& he's good, but at this point I would never trust him while we're at work. :( Any suggestions for crate covers to not allow the urine on the walls?

He seems to be ok fo rthe 4 hours we are away, when we arehome it seems he has to go out every 30 minutes. do we need to lessen that to help him "build his bladder"?

hope you can help. He's learned everything else we've trained him, but seems he's bored or mad at us.....
Thank you.

Answer
The only answer to chewing for many dogs is to crate them whenever you can't watch them.  I think some dogs eliminate in the crate as a protest.  You can reduce the effectiveness of protest by putting a rack in the crate.  Pet stores sell ready made ones.  I use a cheap length of closely spaced wire closet shelving.  

Might try leaving a Kong filled with peanut butter in the crate with him.  He will be too busy licking it out to worry about being shut in the crate.  It will last even longer if you freeze it.