Can I place the balloon near the house to freeze?

No. It is best to place the balloon filled with water outside to freeze at least 10-15 feet from the house and not on decking or stone work.

Why? The house emits heat and the central cavity of the globe that is created while freezing will be off to one side - toward the house. The outside of the globe is exposed to the cold air, and so the ice of the globe will freeze from the outside in. Therefore, if one side is even slightly warmer (in this case caused by the heat of the house) the inside chamber will develop toward the heat.