Lab - weird behavior

Question
We have a black lab that is about 15 months old, had her for a year.  For the past 4 months or so have been able to leave her in the house for hours - including up to 8 by herself with no problems, unless you leave out shoes. She is a great family pet now.  But for the past three days we have had an issue.  1st day, after only about 1 1/2 hours alone, she chewed a hole (about 2 inches in diameter) in a stair that is carpeted, then the next day even after being punished, made it a little bigger, and this being the third day she completely detroyed it.  Any thoughts on why now?  What we can do?

Thanks,

Dena

Answer
Sorry, I have to go out of town leaving a bunch of questions unanswered.  May be able to get back Sunday.

Usually it is a good idea to visit the vet when there is a sudden change in  behavior.  If she isn't spayed, it could be part of the flaky behavior that starts as she comes into season.  Most likely it is a matter her maturing and needing more diversion.  Your house and dog will be much safer with the dog in a crate when you are away.  The dog may be happier in its den than loose in the house.  It relaxes, it feels safe in its den.  It rests, the body slows down reducing the need for water and relieving its self.  Dogs that have been crated all along do very well.  Many of them will rest in their crates even when the door is open.  I think the plastic ones give the dog more of a safe, enclosed den feeling.  They are harder for dogs to open too.    Metal ones can be put in a corner or covered with something the dog can't pull in and chew.  Select
a crate just big enough for the full grown dog to stretch out in.

Leave it some toys.  Perhaps a Kong filled with peanut butter.  Don't leave
anything in the crate the dog might chew up.  It will do fine without even any
bedding.  You will come home to a safe dog and a house you can enjoy.

A dog that has not been crated since it was little, make take some work.
Start out just putting its toys and treats in the crate.  Praise it for going
in.  If you have been able to trust it with any bedding, put that in the crate.
Feed it in the crate.  This is also an easy way to maintain order at feeding
time for more than one dog.

Crated or not, 8 hours is a long time to leave a dog.  Have you tried to find a neighbor or a professional dog walker to give her a mid day break?