Buy-to-Let in the UK: Is It Still Profitable After Section 24?

The allure of UK property investment remains strong, often headlined by tempting gross rental yields that suggest a healthy, passive income. Potential landlords see figures north of 6% and envision a straightforward path to financial freedom. This initial calculation, however, is where the first and most expensive mistake is made. The landscape has been fundamentally reshaped by tax changes, most notably Section 24, which has rendered simple yield calculations dangerously misleading for many investors.

The common advice often pivots to simple solutions, like moving a portfolio into a limited company, as if it were a universal panacea. While a valid strategy for some, it comes with its own set of costs and complexities, including higher mortgage rates and significant upfront transfer taxes. This superficial guidance often overlooks the intricate web of other financial pressures, from tenant-related risks like rent arrears to the spiralling costs of regulatory compliance with EPC ratings and the critical details of inheritance tax planning.

But what if the key to profitability isn’t found in chasing the highest gross yield, but in meticulously managing the dozens of small, hidden costs that erode it? The truth is that modern buy-to-let success is a game of marginal gains. It’s about understanding the precise impact of tax on your personal circumstances, stress-testing your financing against rate hikes, and leveraging every legal allowance available. Profit is no longer a given; it’s engineered through financial diligence.

This article will provide a realistic, consultant-led breakdown of the true costs and opportunities in the post-Section 24 environment. We will dissect the illusion of high yields, provide advanced strategies for mitigating risk, and explore the structural decisions that separate profitable landlords from those subsidising their tenants’ housing.

Why a 6% yield might actually be a loss after tax and maintenance?

The headline figure that attracts many to buy-to-let is the gross rental yield. With data showing average UK buy-to-let gross rental yields reaching around 6.9% in 2024, the investment appears robust. However, this figure is a dangerous illusion. It fails to account for the single biggest factor affecting profitability for many landlords today: Section 24 of the Finance Act 2015. This legislation fundamentally changed how rental income is taxed for individuals, and its impact can be severe enough to wipe out all profit on a leveraged property.

Before Section 24, landlords could deduct all their finance costs, including mortgage interest, from their rental income before calculating their tax bill. Now, this deduction has been replaced by a 20% tax credit on mortgage interest payments. For a basic-rate taxpayer, the change is neutral. But for a higher-rate (40%) or additional-rate (45%) taxpayer, it’s a financial bombshell. You are now taxed on your rental income *before* accounting for mortgage interest, pushing many into a higher tax bracket and creating a tax liability that can exceed the actual cash profit.

Consider a practical example. A higher-rate taxpayer owns a property generating £24,000 in annual rent with £12,000 in mortgage interest. Post-Section 24, their tax bill can be thousands of pounds higher than before, as the relief is capped at the 20% basic rate. This “profit illusion” means that a seemingly healthy 6% gross yield can quickly become a negative net yield once realistic maintenance costs (typically 1-2% of property value annually), letting agent fees, insurance, and the true tax burden are factored in. The investment is no longer about the income it generates, but the tax it creates.

How to vet tenants to avoid 6 months of unpaid rent?

Beyond tax and finance, the single greatest operational risk to a landlord’s cash flow is a non-paying tenant. A period of rent arrears doesn’t just mean a loss of income; it triggers a cascade of costs, including legal fees for eviction (a process that can take over six months) and potential damage to the property. With recent data showing the average rent arrears claim reaching £2,597, and rising, tenant vetting is not an administrative task—it is a critical form of financial risk management.

Standard referencing, which often stops at a simple credit score and employer letter, is no longer sufficient. A sophisticated approach is needed to identify red flags that predict future financial distress. This means going beyond the surface-level checks to build a complete picture of a prospective tenant’s financial stability and rental history. True diligence lies in analysing the details of their credit report, conducting forensic-level checks with previous landlords, and cross-verifying information through digital channels.

An effective vetting process acts as a firewall, protecting your investment from predictable losses. It requires a more investigative mindset, focusing on patterns of behaviour rather than single data points. This deeper level of scrutiny is the most cost-effective insurance a landlord can have against the significant financial and emotional drain of rent arrears and eviction proceedings.

Interest Only: Is it a cash flow hack or a debt trap?

For decades, the interest-only (IO) mortgage was the default choice for buy-to-let investors, prized for its ability to maximise monthly cash flow. By only servicing the interest, landlords could keep their outgoings low and report a healthy monthly profit. However, in the current economic climate of higher interest rates and the Section 24 tax regime, the IO mortgage has transformed from a cash flow tool into a potential capital structure trap. The strategy’s high sensitivity to rate changes can rapidly erode profitability, and the fact that no capital is repaid leaves the investor fully exposed to property market downturns.

The market is already reacting to this heightened risk. UK Finance reports an 18.5% decline in the number of outstanding IO mortgages in just one year, as both lenders and savvy investors move towards more stable capital repayment models. While a repayment mortgage results in a lower monthly cash flow on paper, it builds equity, systematically de-risks the investment over time, and is less volatile in the face of interest rate hikes. An IO mortgage offers no such safety net; the entire £200,000 loan on a £200,000 mortgage will still be outstanding after 25 years.

This paragraph introduces the table below, which breaks down the stark financial differences. As you can see, a 1% rate rise has a disproportionately larger impact on the monthly payments of an IO mortgage, demonstrating its inherent cash flow volatility.

Choosing an IO mortgage today requires a robust and tested exit strategy. Without a clear plan to repay the capital, the landlord is simply gambling on long-term house price inflation to clear the debt. For a risk-averse investor, the predictability and forced-savings nature of a capital repayment mortgage is often the more prudent, if less cash-flow-rich, choice.

As this image suggests, financial modelling is key. The decision should not be based on today’s cash flow but on a stress-tested forecast that accounts for future interest rate scenarios. This careful analysis is fundamental to avoiding a long-term debt trap.

The EPC error that could make your property illegal to rent

Beyond taxes and finance, a significant and growing cost for landlords is “regulatory drag”—the financial burden of complying with ever-tightening government rules. The most pressing of these relates to the Energy Performance Certificate (EPC). Currently, a property in England and Wales must have a minimum EPC rating of ‘E’ to be legally let to new tenants or renew an existing tenancy. Failing to meet this standard doesn’t just result in a fine; it renders the property illegal to rent, cutting off income entirely.

The government has confirmed that this requirement will become even stricter, with all private rental properties needing to achieve an EPC rating of ‘C’ by 2030. For landlords with older, less efficient housing stock, this represents a major capital expenditure. While there is a cost cap on the improvements a landlord is required to make, under current MEES regulations, this stands at £3,500 per property. However, for the upcoming ‘C’ rating requirement, the estimated cost cap is expected to rise to £10,000.

Many landlords are unaware that an EPC rating can be challenged. If an assessor has overlooked recent improvements, such as a new boiler, insulation, or double-glazed windows (with FENSA certificates as proof), a formal reassessment can be requested. Furthermore, if the cost of necessary improvements exceeds the cap, landlords can register for an exemption. This requires diligent record-keeping, including obtaining three independent contractor quotes to prove the high cost and documenting any refusal of consent from freeholders or planning authorities. Without this paperwork, you have no defence and are liable for the full cost of upgrades and potential fines. This is a ticking financial time bomb in many portfolios.

When to move your portfolio into a Limited Company?

In response to the Section 24 tax changes, incorporation has become the primary strategy for landlords seeking to mitigate their tax burden. By holding properties within a limited company (often a Special Purpose Vehicle or SPV), the restrictive 20% tax credit rule is bypassed. The company can deduct 100% of its finance costs as a business expense before being subject to Corporation Tax, which is typically lower than personal higher-rate income tax. The trend is undeniable, with research showing a 332% increase in the number of buy-to-let companies since 2016.

However, incorporation is not a one-size-fits-all solution and can be a costly mistake if not carefully considered. The two main drawbacks are financing and transfer costs. Mortgages for limited companies are often more expensive, with higher interest rates and arrangement fees than personal buy-to-let products. More significantly, transferring an existing, personally-owned portfolio into a company is treated as a sale and purchase. This can trigger a substantial bill for both Capital Gains Tax (CGT) on the growth in value and Stamp Duty Land Tax (SDLT) on the market value of the properties being transferred. These upfront costs can be prohibitive, often wiping out the potential long-term tax savings.

The table below highlights the key differences between personal and limited company ownership, illustrating the trade-offs involved.

Generally, incorporation is most viable for landlords with larger portfolios (often six properties or more) who are higher-rate taxpayers and are looking to acquire new properties directly into the company structure. For an investor with one or two properties, the administrative and financing costs of running an SPV often outweigh the tax benefits. The decision requires a detailed financial projection from a qualified tax advisor.

How to legally use a spouse’s tax allowance to reduce household bills?

One of the most effective and underutilised tax planning strategies for landlords who co-own property with a spouse or civil partner is the reallocation of rental income. By default, HMRC assumes that any income from a jointly-owned property is split 50:50 between the owners, regardless of who contributed what to the purchase. However, if one partner is a basic-rate taxpayer and the other is a higher-rate taxpayer, this default split is highly inefficient, pulling more of the profit into the higher tax bracket.

It is perfectly legal to change this. By using a legal document called a Declaration of Trust and submitting a Form 17 to HMRC, you can declare an unequal split of the beneficial interest in the property. This allows you to allocate a larger portion of the rental income (e.g., 90%) to the lower-earning partner, thereby utilising their basic-rate tax band more effectively and reducing the household’s overall tax liability. This strategy requires changing the property ownership from ‘Joint Tenants’ (where ownership automatically passes to the survivor) to ‘Tenants in Common’ (where each partner owns a distinct share).

This image of a couple planning together perfectly captures the collaborative nature of this strategy. To implement it correctly, you must follow a clear legal process:

1. Convert to ‘Tenants in Common’: A solicitor must be engaged to legally change the property’s ownership structure, which is the prerequisite for allocating unequal shares.
2. Prepare a Declaration of Trust (Form 17): This legal document outlines the agreed-upon beneficial interest split (e.g., 90:10). This split should ideally reflect the actual contributions each partner has made to the property.
3. Gather Evidence: Collect property deeds, mortgage statements, and bank records showing each party’s financial contributions to support the declared split in case of an HMRC enquiry.
4. File Form 17 with HMRC: The form must be submitted to HMRC within 60 days of being signed to officially recognise the new income split for tax purposes.
5. Model CGT Implications: Be aware that this split will also apply to any Capital Gains Tax liability when the property is sold. This must be factored into the long-term planning.

The paperwork oversight that costs heirs £175,000 in allowances

For many landlords, their property portfolio represents the largest part of their estate. Yet a simple paperwork oversight can lead to a significant and entirely avoidable Inheritance Tax (IHT) bill for their heirs. The key issue revolves around a valuable tax allowance known as the Residence Nil-Rate Band (RNRB). This provides an additional IHT-free allowance of £175,000 per person (for a total of £350,000 for a married couple) when a main residence is passed to direct descendants like children or grandchildren.

However, a critical mistake many landlords make is assuming their buy-to-let portfolio will automatically benefit. Many wills are structured using discretionary trusts to manage assets, but this can inadvertently cause the RNRB allowance to be forfeited. The rules are strict: the property must be “closely inherited,” meaning it passes directly to lineal descendants. Complex trust structures can break this direct link, resulting in the loss of the allowance. Furthermore, it’s a common misconception that a buy-to-let portfolio qualifies for Business Property Relief (BPR), which offers 100% IHT exemption. In reality, standard buy-to-let businesses are treated as investments by HMRC and almost never qualify for BPR.

Another crucial error is related to property ownership. Most couples own their home as ‘Joint Tenants,’ meaning the property automatically passes to the surviving partner upon death. While simple, this can be inefficient for IHT planning. Changing ownership to ‘Tenants in Common’ allows each partner’s share to be passed on via their will, enabling the use of both partners’ IHT allowances and the RNRB more effectively. Failing to address these structural points in your will and property deeds is a common form of “allowance forfeiture” that can cost a family hundreds of thousands in tax.

• Ensure your will explicitly passes property to direct descendants to secure the £175,000 RNRB.
• Convert joint ownership to ‘Tenants in Common’ to enable more flexible IHT planning.
• Do not assume your portfolio qualifies for Business Property Relief; it is highly unlikely.
• Have your will reviewed by an IHT specialist to ensure trust structures do not inadvertently block the RNRB.

Commercial Property or Residential: Which Yields More for £200k?

Faced with the increasing tax and regulatory pressures of residential buy-to-let, many investors with a £200,000 budget are now considering commercial property as an alternative. At first glance, commercial property appears attractive. Yields are often higher, and leases are typically longer and on a “Full Repairing and Insuring” (FRI) basis, meaning the tenant is responsible for all costs of maintenance, repairs, and insurance. This creates a seemingly more passive and predictable income stream compared to the hands-on management required for residential tenancies.

However, the risks are different in nature and can be more severe. While residential property has a constant underlying demand, the demand for a specific type of commercial unit (e.g., a high street shop or a small office) can be highly sensitive to economic cycles. A vacant commercial unit can remain empty for a year or more, resulting in zero income and the landlord becoming liable for 100% of the business rates after an initial three-month exemption period. This contrasts with residential property, where void periods are typically much shorter.

With a £200,000 investment, a residential investor might buy a single flat or small house. A commercial investor might acquire a small retail unit, a workshop, or a garage. The residential asset benefits from a more liquid market and greater potential for capital appreciation driven by the national housing shortage. Commercial property values are more closely tied to the strength of the lease (the “covenant strength” of the tenant) and the prevailing yield in that specific sector. A strong tenant like a Post Office or a national pharmacy chain offers security, but securing such an asset for £200k is challenging. More likely, an investor at this level will be dealing with a small independent business, which carries a higher risk of default.

Ultimately, the choice depends on the investor’s risk appetite. Residential property offers lower but more stable yields and stronger capital growth prospects, albeit with higher management and tax burdens. Commercial property offers the potential for higher, more passive income, but with greater risk from extended void periods and a market more vulnerable to economic shocks.

Profitability in UK buy-to-let is no longer an accident of a rising market; it is the result of deliberate and informed financial strategy. Success demands a shift in mindset—away from the simplistic gross yield and towards a detailed, post-tax net return analysis. As we have seen, this means stress-testing your mortgage structure, proactively managing regulatory costs, and structuring your ownership to maximise every available tax allowance. For a potential landlord debating the viability of this investment, the logical next step is to move from general principles to specific numbers. An analysis of your personal financial situation by a qualified professional is essential to build a realistic forecast and determine if property investment can truly meet your goals.