Help with a Dog House Project Needed Desperately?

I would like to create a doghouse for my 9 month Jack Russell Terrier. I was thinking about making it one floor however I then began thinking about 2 floors. I want to make it out of foamboard; more like project foamboard. So the house will have 2 floors. The first floor has a dog door and the left and back wall have plastic windows (I have this part figured out already) the right side has stairs. The doghouse is going in the basement as more of a playpen so I am not concerned about weather proofing it. So anyways, I was thinking about making the stairs out of foamboard by cutting out rectangular pieces and gluing them together. If I make it thick enough, I'm sure it can most definitely hold her weight. Right now, she weighs 19lbs and is lean (She's not overweight). She is at 8-9 months and will probably stop growing at 12 months or 1 year. The stairs are on the outside of the dog house but attatched. The stairs lead upstairs to a floor that has foam fencing to keep her from falling out. I was planning of doubling up the ceiling but my biggest fear is that it is going to collapse and hurt her. How thick should the foamboard be to hold her weight? Can foamboard actually hold weight? Should I just make the doghouse bigger for her to play in and exclude the upstairs floor? Should I put the stairs inside the house to provide more ceiling support? Also what is the biggest foamboard piece possible to buy(in michaels)? Lastly, how much will the foamboard cost in Michaels? Thanks.Also, the dog will probably weight 25 pounds at final growth.For your information it is just a playpen to put in the basement. I don't keep her in there. She is crate trained and I have had 3 Jack Russell Terriers before who have lived until age 18. I know they are energetic. I am not stupid. You're answers were absolute crap. We own 1 acre.For your information it is just a playpen to put in the basement. I don't keep her in there. She is crate trained and I have had 3 Jack Russell Terriers before who have lived until age 18. I know they are energetic. I am not stupid. You're answers were absolute crap. We own 1 acre.That was meant for the 2nd comment. First one was helpfulI live in a 2 floor big house the dogs have access everywhere.

DON'T. Dogs eat foam board, and it forms a wad in their intestines - and blocks them. It also won't be anything she wants to be in on or near, because it won't hold her weight - or her attention. A Jack Russell Terrier needs a LOT of entertainment - they can be very destructive if they don't have anything to do. You CANNOT keep her in the basement, and if that is all you have to offer, it is time to look for a better home. These dogs are bred to hunt rodents constantly, and are fierce, strong, and hyperactive. The LAST thing they should be is left to their own devices inside a house. If you want to build a dollhouse, go ahead. But this dog is far from being the doll you think she is. DO not under any circumstances leave her in the basement, and certainly not near anything made of foamcore.

Ugh. Hate when someone has no clue about Jack Russell terriers. Just return it now to the breeder so it can be rehomed if you plan to keep it in this ridiculous thing you want to call playpen in the basement. You really think a JACK is going to be happy with that then you have no understanding of the breed.