Buy to Let (BTL) is a type of mortgage used by clients who intend to purchase property but rent it out to tenants rather than live in it. BTL mortgages differ from residential mortgages in that for a BTL mortgage the lender will generally require their surveyor to estimate the likely rental income of the property if it is let out. This is usually the biggest factor in determining how much the lender will lend.

Lenders will not usually lend more than 85% of a property value if it is going to be let out (though some lenders are now offering loans at 90% loan to value). One of the reasons for this is that if the property has no tenant and the borrower is reliant on the rental income, they are more likely to keep paying their residential mortgage than their buy to let mortgage. For most people keeping their residential home is the main priority so in the eyes of the lender buy to let's are a higher risk to lend money on.

Generally buy to let purchases are done on a self financing basis. This means that as long as the rental income is sufficient your personal income is of less importance. Some lenders do require a minimum personal income but generally as long as rental income is 125-130% of the monthly mortgage payments there will be lenders available that will consider offering a mortgage.

Applicants with adverse credit are perceived by lenders to be a higher risk, and therefore generally only qualify for higher rates. If you have bad credit then it may be more difficult to find a lender that can offer a loan at 85% of the property value, however this may be possible.