Buy-to-Let Remortgage

How BTL Remortgaging Differs From Residential

On a residential remortgage, a lender mainly looks at your salary, outgoings and credit file. On a buy-to-let remortgage, the property itself has to "pay" for the mortgage through the rent it generates. Lenders run a rental stress test — your expected rent must cover the mortgage payment by a specific margin, typically between 125% and 145%, stress-tested at a notional rate of 5.5% or higher.

Other key differences include:

• Higher deposits — BTL deals usually require at least 25% equity; the best rates start at 40% equity (60% LTV).
• Higher rates and fees — BTL mortgages typically cost 0.5%-1.5% more than residential deals of the same LTV, with arrangement fees often 1.5%-3% of the loan.
• Minimum income rules — most BTL lenders still want to see £25,000 gross personal income outside of rental profits.
• Regulation — most BTL lending is unregulated by the FCA, unless it's a "consumer buy-to-let" (where you previously lived in the property or inherited it).

The takeaway for landlords: the playbook you used for your home remortgage will not work here. You need a broker who understands rental cover, ICR tiering and the differences between high-street BTL lenders and specialist portfolio lenders.

Understanding ICR and the Rental Stress Test

The Interest Coverage Ratio (ICR) is the single most important number in a BTL remortgage. It determines how much you can borrow against a given rent.

The formula is straightforward: Monthly rent / (Loan amount × stress rate / 12) × 100 = ICR %. The ICR percentage your property achieves must be at least as high as your lender's minimum, usually 125% for basic-rate taxpayers and 145% for higher-rate taxpayers or limited companies.

Borrower type	Typical ICR required	Typical stress rate
Basic-rate taxpayer, 5-yr fix	125%	Pay rate or 5.5%
Higher-rate taxpayer, 2-yr fix	145%	5.5%-7%
Limited company SPV	125%	Pay rate + 1% or 5.5%
HMO / multi-unit	145%-170%	5.5%-7%

Top tip: five-year fixes often benefit from relaxed stress tests (using the pay rate rather than a 5.5% notional rate), which can materially increase how much you can borrow. If your property is rent-restricted, switching to a five-year deal is often the difference between a remortgage that works and one that doesn't.

Specialist BTL Lenders You Should Know

Unlike the residential market, the BTL landscape is dominated by specialist lenders that rarely advertise to the public. Many are only accessible through intermediaries. The lenders that will accept your case depend on the property type, ownership structure and portfolio size.

Mainstream BTL lenders — The Mortgage Works (part of Nationwide), BM Solutions (Lloyds Banking Group), Accord Buy-to-Let (Yorkshire Building Society), Barclays BTL and NatWest BTL. These tend to offer the sharpest rates but have the strictest criteria on income, credit and portfolio size.

Specialist BTL lenders — Paragon, Precise Mortgages, Kent Reliance, Landbay, Foundation Home Loans, Fleet Mortgages, Aldermore, Shawbrook and Molo. These are the go-to names for portfolio landlords, limited company SPVs, HMOs and multi-unit blocks. Rates are higher but criteria are far more flexible.

Private and challenger banks — InterBay, Together, LendInvest, Hampshire Trust, Cambridge & Counties. Useful for complex situations: expats, non-standard construction, large portfolios (20+ properties) or landlords with recent adverse credit.

No single lender suits every case. A property that's rejected by Paragon might be approved by Landbay the same day. This is why using a whole-of-market BTL broker is typically non-negotiable — they place cases with the right lender first time.

Personal Name vs Limited Company (SPV) Remortgaging

Since the phased introduction of Section 24 between 2017 and 2020, higher-rate taxpayers holding BTL properties in their personal name can no longer deduct mortgage interest from rental income for tax purposes. Instead, they receive a 20% basic-rate tax credit. For higher-rate (40%) and additional-rate (45%) taxpayers, this can turn a previously profitable rental into a loss-making one.

Many landlords have moved, or are considering moving, to a limited company structure (usually a Special Purpose Vehicle, or SPV, with SIC codes 68100, 68209, 68320 or 68201). Inside a limited company:

• Mortgage interest is a fully deductible expense against rental profits.
• Profits are taxed at corporation tax rates (currently 19%-25%) rather than personal income tax rates.
• Profits can be retained in the company to fund further purchases, reducing personal tax leakage.

However, transferring an existing personally-held property into a company is a disposal for Capital Gains Tax (CGT) and usually triggers Stamp Duty Land Tax (SDLT) at the higher (3% surcharge) rate. It rarely makes sense for a single property, but for portfolio landlords or those buying more property it often does. Always consult an accountant before restructuring — and be aware that some lenders (e.g. The Mortgage Works, Paragon, Kent Reliance, Foundation) actively compete on limited company BTL remortgage rates.

Documents You'll Need for a BTL Remortgage

BTL underwriting is more document-heavy than residential. Getting paperwork ready upfront can save two or three weeks of application drag.

For all BTL remortgages:

• Current mortgage statement and redemption figure.
• Assured Shorthold Tenancy (AST) agreement for the property.
• Last three months of bank statements showing rent receipts.
• Gas safety certificate, EPC (min. rating E, usually C expected by 2028 under proposed MEES rules) and EICR.
• Buildings insurance schedule.
• Last two years' SA302s and tax year overviews (if self-employed).
• Three months' personal payslips (if employed) to prove the £25,000 minimum income.

Additional documents for limited company BTL:

• Companies House print-out showing SIC codes and directorships.
• Last two years of filed company accounts.
• Personal guarantees from all directors (standard for SPV lending).

For portfolio landlords (4+ mortgaged BTLs): a full portfolio schedule listing every property, along with an asset and liability statement and a business plan. The PRA requires portfolio landlords to be stress-tested across their entire portfolio, not just the subject property.

Common Pitfalls to Avoid

We see the same handful of mistakes trip up BTL landlords when remortgaging. Most are avoidable with good advance planning.

Leaving it too late — Your current fix ending? Start six months early. BTL cases regularly take 10-12 weeks to complete due to ICR calculations, portfolio reviews and, for limited companies, personal guarantee paperwork. Landlords who wait until the last month often end up on the lender's standard variable rate for several weeks — an expensive mistake when SVRs commonly exceed 7%-9%.

Under-declaring rent — Be honest about actual rent received. Lenders compare to the surveyor's estimated market rent and to HMRC records on file — inflating rent to pass the ICR test is mortgage fraud. Equally, don't under-declare: if your rent is below market, raise it at the next renewal cycle before remortgaging.

Forgetting the minimum income rule — If your personal (non-rental) income has dropped below £25,000, certain lenders (e.g. BM Solutions, The Mortgage Works) will decline the case. Specialist lenders like Landbay, Paragon and Kent Reliance have "no minimum income" products you should look at.

Ignoring EPC rules — From 2025/2028 (rules still being finalised), new tenancies may require an EPC rating of C or above. Some lenders already refuse to lend on F/G-rated properties and offer rate discounts on EPC-C or better. Plan any EPC upgrade works well ahead of applying.

Top-slicing confusion — If the rent doesn't quite hit the ICR, some lenders (Aldermore, Foundation, Precise) allow "top-slicing" — using surplus personal income to bridge the gap. Not every broker knows which lenders offer this.

Mixing unregulated and regulated BTLs — If you're remortgaging a property you used to live in (a "consumer BTL"), it falls under FCA rules and requires a specific authorisation from your broker. Many specialist lenders don't offer consumer BTL products, so getting clarity early avoids dead-end applications.

When Is the Right Time to Remortgage?

The optimal remortgage window depends on your current product and the wider rate cycle. For most landlords, the golden rules are:

• Start six months before your deal ends. Most BTL lenders let you secure a rate up to six months in advance of completion, and many allow a switch to a lower rate if one emerges before completion.
• Don't break expensive ERCs without modelling the net gain. A 3% ERC on a £200,000 loan is £6,000 — only sensible to break if the new rate saves materially more over the fix period.
• Act fast when you're on SVR. A typical SVR of 8% on a £150,000 interest-only BTL costs £1,000 per month. Remortgaging to a 5% fix saves £375 per month — £4,500 per year of recovered cashflow.
• Watch the 5-year swap rate. When 5-year swaps dip below 4%, mortgage rates follow 4-8 weeks later. Tracking swaps can help you time a rate lock.

If your circumstances have improved (higher credit score, lower portfolio LTV, EPC upgrades completed) since your last remortgage, you may qualify for materially better pricing tiers this time. A mid-cycle broker review, even without a deal ending, can reveal £1,000-£3,000 of annual savings per property.