I have a 6 month old dog that is chewing my house to bits. He has been castrated and it hasn't made any?

difference to his behaviour. He has chewed the skirting, door frame and two doors in the kitchen and every morning I am finding another patch where he's chewed it during the night or during the day whilst I'm at work.(He's only alone for approx 4 hrs max) . He has stacks of chewy toys and hide bones but he prefers wood obviously. He is very close to looking for a new home if I can't cure this problem.