Turn room rental into biz income stream to qualify for mortgage

[Jeffrey S Bratcher]

I rent out the third floor of my home. I declare the money on my personal taxes..take deductions...and use the profit to pay my current mortgage. 

But what if I started an LLC...had my tenants pay that LLC...then took deductions and instead of paying personal taxes and paying my personal mortgage...I instead used the cash flow to pay the mortgage on an investment property.

Can I do that thru a one owner LLC? Should it be some other kind of business entity that is not a pass thru variety? What newbie mistake or insight am I missing?

How long would a bank want to see this cash flow before considering it when making a loan on an investment property.  Does the business then buy the investment property or do I?  Basic questions I am sure but thats where I am at the moment.  

The get real issue is that I loke using that money to pay my mortgage. I really just want to use it to qualify for the investment property. Then I would use the investment property rent to pay that mortgage and continue to use the third floor income to lay my personal mortgage. 

Have I just answered my own question? Use the third floor income to qualify for second home..but use the rental income to pay that mortgage and keep that money paying my personal mortgage. What are the advantages of keeping that rental money in a one man LLC? Is there a way to put the money in the LLC..and disburse it to pay my personal mortgage?