Planning Your Next Property Purchase: SDLT Implications

The 5% Additional Dwelling Surcharge

Finance Act 2003 Schedule 4ZA introduced the higher rates for additional dwellings in April 2016. As of October 2024, the surcharge is 5 percentage points above the standard residential rates on every band. This means that instead of paying 0%/2%/5%/10%/12%, a buyer of an additional dwelling pays 5%/7%/10%/15%/17% across the same bands.

The surcharge is assessed at the effective date (completion date) by reference to whether the buyer owns — or has a major interest in — any other residential property at that point. SDLTM09750 provides HMRC's detailed guidance on what counts as "additional dwelling" ownership. Our second home complete guide covers all aspects of the surcharge in detail.

Replacement Main Residence Exception

Schedule 4ZA paragraph 3 provides the most important exception to the additional dwelling surcharge: the replacement of a main residence. If, at completion, you are replacing your only or main residence — meaning you are selling the previous main residence as part of the same transaction or have already sold it — the surcharge does not apply.

The exception works because the test in Sch 4ZA is not simply "how many properties do you own?" but rather "are you purchasing an additional dwelling?". A buyer who sells their existing home on the same day as buying a new one, and who does not own any other residential property, does not become an additional dwelling buyer.

See our detailed guide on replacement main residence rules for full eligibility criteria, including what happens with shared ownership and part-ownership scenarios. SDLTM09770 covers the exception in the HMRC manual.

The 36-Month Refund Window

In many transactions, the buyer completes on their new property before completing the sale of their previous main residence — for example, to secure a new property in a competitive market or to avoid being in a chain. In these cases, the additional dwelling surcharge is payable upfront at the higher rates, since the buyer technically owns two residential properties at the moment of purchase.

However, FA 2003 Sch 4ZA para 3(6) provides a refund mechanism: if the previous main residence is sold within 36 months of the new purchase completing, the buyer can claim back the surcharge using SDLT60. The full surcharge is refunded — not merely the difference between rates.

The refund claim is made on SDLT60 and must be submitted to HMRC within 12 months of the disposal of the previous main residence (i.e., within 12 months of selling the old home, provided that sale was within the 36-month window).

Buying a Second Home

If you purchase a property while retaining your existing home (and neither sale nor replacement main residence exception applies), the 5% surcharge applies to the entire purchase. This is the straightforward "second home" scenario that applies to holiday homes, rental properties, and properties for family members.

The surcharge applies regardless of the purpose of the additional property — HMRC does not distinguish between a holiday cottage and a buy-to-let investment. The key question is simply whether you own (or have a major interest in) another residential property at the completion date.

Use our second home calculator to calculate the exact SDLT liability including the surcharge for any property price.

Expanding a Property Portfolio

Landlords and property investors face the additional dwelling surcharge on every residential property purchase, without exception (unless a specific relief applies). There is no portfolio relief or landlord exception — the surcharge applies from the first additional property onwards.

This significantly affects the economics of portfolio expansion. A landlord purchasing a £250,000 rental property pays £11,250 in SDLT at additional dwelling rates (5% on the full £250,000), compared to £2,500 at standard rates. Over a 10-property portfolio expansion, the additional cost could exceed £85,000.

SDLTM09780 and SDLTM09790 provide HMRC's guidance on the calculation of the additional dwelling surcharge for linked transactions and portfolio purchases.

Company Purchases

Companies and other non-natural persons (trusts, partnerships in certain cases) face a flat 17% SDLT rate on residential property purchases above £500,000 under FA 2003 s55 and Schedule 4A (the Annual Tax on Enveloped Dwellings regime). This flat rate applies to the entire purchase price — there is no progressive rate structure.

For properties below £500,000, companies pay the standard residential rates plus the 5% additional dwelling surcharge (since a corporate body does not occupy a main residence). In most cases this makes corporate acquisition significantly more expensive than personal purchase.

The 17% flat rate makes corporate purchase financially disadvantageous for most residential property in England. Company structures may make sense for very high-value portfolios where other tax efficiencies (income tax, inheritance tax, business rates) outweigh the higher acquisition cost. Always obtain specialist advice before structuring property purchases through a company.

Timing Strategies

The timing of sale and purchase relative to each other is the most powerful tool for managing SDLT on a move. Key strategies include:

Worked Examples

Example 1: Buying before selling (£450,000 new home)

Example 2: Portfolio investor buying a third property (£300,000)

Common Traps

Frequently Asked Questions