A book about an infinite mansion

[Veda]

So in this book the main character is a boy and he has asthma i think and his relative has a giant mansion and so when his relative dies he moves to this mansion and the mansion is still being built and its very very very big . So when he goes in this mansion he soon discovers that theres like these dogs in the mansion and when they get mad they turn into wolves i think and yeah thats all i remember Also the cover of the book is about 3 wolves looking at you with the mansion in the background please help me find this book ive been trying to find it for a year sorrry for not too many details i don’t remember that much of it

[Rainbowheart]

When did you read it?

Is this book for kids, teens, or adults?

[Lobstergirl, au gratin]

Veda, please add genre and plot details to your topic header. Use the little edit link.