Keep the key parts of a buy-to-let case in view: SDLT on additional property, rental-income reporting, landlord duties, lender permission to let and the criteria checks that shape borrowing.
SDLT
Additional residential properties usually face the 5% surcharge
HMRC
The first £1,000 of property income can fall within the property allowance
Criteria
Published lender criteria can change by tax band, property type and loan-to-value
Key Checks
A buy-to-let purchase needs more than a deposit and a headline rent figure. The numbers only make sense once the tax position, lender criteria and landlord duties are in view.
Many buy-to-let purchases are treated as additional residential property purchases for SDLT, so the 5% higher-rate charge can apply on top of the standard bands. That needs to be modelled before you compare gross yield tables.
The property allowance can help at lower levels of income, but reporting obligations still matter once income moves beyond the relevant thresholds. Good cash flow does not remove that responsibility.
Published criteria pages show different rental cover and stress expectations by property type, tax position and loan-to-value. A case can look acceptable on one lender's rules and fail on another without any contradiction.
Safety, deposit protection, right-to-rent checks in England and lender permission are all part of the operating reality. They should be handled early, not left until after the purchase completes.
Lender Checks
A published lender example is useful because it shows how quickly the numbers can change once tax band, property type and loan size enter the picture.
| Published Paragon criteria point | Current example | What it tells you |
|---|---|---|
| Single self-contained properties | Paragon publishes a 125% ICR for basic-rate taxpayers and limited companies, and 140% for higher-rate or additional-rate taxpayers. | Tax band changes the stress test, so one flat ICR assumption is not enough for serious planning. |
| HMOs, multi-unit blocks and other property types | The same published criteria use 130% for basic-rate taxpayers and limited companies, and 145% for higher-rate or additional-rate taxpayers. | Property type matters as well as borrower type, so the lender check has to match the asset you are buying. |
| Loan-to-value limit | Paragon\'s non-portfolio criteria summary shows up to 80% LTV for loans up to £750,000 and up to 75% LTV for loans up to £1,000,000. | Maximum leverage is also tied to loan size, not just to the headline idea of buy-to-let borrowing. |
Before you commit to an offer or pay valuation fees, check the exact product criteria, the tax-band assumption behind the stress test and the lender\'s LTV cap. That takes longer than relying on a shortcut, but it gives you a more realistic case.
Decision Route
This sequence helps keep the cash-flow model, lender rules and compliance checks connected.
A buy-to-let property can look acceptable on gross yield and still fail when you include void periods, management costs, insurance, maintenance and tax reporting. Build the cash-flow model before you worry about the lender list.
Published lender criteria show that rental cover, stress treatment and maximum loan-to-value can change by product and borrower type. Use lender examples to frame the case, then check the exact product rules before applying.
Rental-income guidance tells you when you need to report income and how the property allowance works, but it does not turn one ownership structure into the automatic answer. Take tax advice before making long-term decisions about personal or company ownership.
Landlord duties sit alongside the mortgage, not behind it. Safety, deposit protection, right-to-rent checks in England and lender permission should all be part of the plan from the start.
Tax and Duties
The mortgage is only one part of the operating model. Landlord duties and rental-income reporting also shape the time, cost and risk of the investment.
Next Tools
The modelling gets more useful once the purchase costs, tax basics and lender checks are already in view.
Model yield, rent cover and cash flow once you know which lender criteria you are trying to satisfy.
Check the additional-property SDLT bill before you decide that the deposit is enough to get the deal done.
Use a separate tax model for exits instead of assuming the purchase structure solves everything.
Pressure-test how the mortgage behaves under repayment or interest-only assumptions.
No. Published lender criteria differ by product, tax band, property type and loan-to-value, so one lender example should never be treated as a market-wide rule.
Often, yes. Many buy-to-let purchases are treated as additional residential property purchases for SDLT, although the position can differ if the purchase is linked to replacing a main residence.
Yes. If you have a mortgage on the property you want to let, you should get permission from the lender before renting it out.
The first £1,000 of rental income can fall within the property allowance. Above that, the reporting route depends on the level of income and expenses, and many landlords will need to tell HMRC or file through Self Assessment.
No. Standard investment buy-to-let is generally outside the FCA's regulated mortgage perimeter, but consumer buy-to-let cases are handled differently and firms carrying on that business should appear on the FCA register.