Buy-to-Let Landlord Summer Checklist 2026: 5 Financial Tasks for July–August

Quick answer

July and August are quiet months for tenants, but for landlords they should be financially active ones. Two deadlines and three strategic reviews deserve attention. Tackle them now rather than in January when everything lands at once.

Task 1: Pay your Self Assessment instalment by 31 July

If your 2024/25 Self Assessment tax bill (rental income plus any other SA sources) was over £1,000 and PAYE didn't cover 80% of your total tax, you owe a second payment on account on 31 July 2026.

The amount is 50% of your 2024/25 SA income tax — the same as the first instalment you paid in January.

Example: You had rental profits of £18,000 and salary of £35,000 in 2024/25. Your SA tax bill (higher-rate tax on rental income above your remaining basic-rate band) was £6,000. Your second payment on account is £3,000 due 31 July.

If you can't pay: Call HMRC Self Assessment helpline (0300 200 3310) before 31 July to set up Time to Pay. Do not wait until August — interest at 7.5% starts from 1 August, and the 5% surcharge adds 30 days after.

If 2025/26 rental income is lower (a void period, reduced rents, increased deductible costs): apply to reduce the payment via SA303 (online via Government Gateway or paper form). Reducing too aggressively triggers interest on the shortfall, but getting a ballpark right is perfectly reasonable.

Task 2: Stress-test your mortgage at 7%

Interest rates may be falling from their 2023–24 peaks, but your buy-to-let mortgage could still be expensive when you remortgage. Now is the time to run the numbers before your current deal ends.

BTL lender stress test:

Most lenders require rental income to cover 125–145% of the mortgage payment calculated at a notional rate of 5.5–7%, even if the actual product rate is lower. This is to ensure the property still stacks up if rates rise.

Example: £200,000 BTL mortgage

If your rental income is below the stress-test threshold, you may not be able to remortgage at the same loan-to-value when your current fix ends. Options:

• Reduce the mortgage balance (overpay before the fix ends, if allowed).
• Accept a higher product rate (lenders offering lower LTV products may use less stringent ICRs).
• Raise the rent if the market permits.

Task 3: Gas Safety Certificate

This is non-negotiable. Under the Gas Safety (Installation and Use) Regulations 1998, every landlord with a gas supply in a rented property must:

1. Have the gas installation checked by a Gas Safe registered engineer at least every 12 months.
2. Keep a record of each check for at least 2 years.
3. Give tenants a copy of the certificate within 28 days of the check.

Check when your current certificate expires. If it lapses, you cannot legally let the property until a new one is obtained. Failure to have a valid certificate is a criminal offence, with fines and imprisonment in serious cases.

Book the check in June–July when engineers are less busy and before the annual autumn rush. Typical cost: £60–£120 depending on the number of appliances.

Note: the same annual requirement applies to oil-fired heating (using an OFTEC-registered engineer). Electric-only properties are exempt.

Task 4: Plan your Section 24 position for 2025/26

Your 2025/26 Self Assessment return is due 31 January 2027. That might seem distant, but Section 24 planning should start now if your tax bill is significant.

How Section 24 works in practice

Section 24 (Clause 24 of the Finance Act 2015, fully effective from April 2020) means that for individually-owned residential rental properties:

• You cannot deduct mortgage interest from rental income.
• Instead, you get a 20% tax credit on the total finance costs.

Example: Higher-rate landlord with £1,200/month mortgage interest

Section 24 effectively doubles the tax bill for this landlord compared with the pre-2020 rules. The gross rental yield looks fine; the post-tax cashflow is the problem.

What you can deduct (not affected by Section 24)

• Letting agent fees.
• Property maintenance and repairs (not improvements).
• Buildings and contents insurance.
• Ground rent and service charges.
• Accountancy fees attributable to the rental.
• Council tax and utilities when paid by the landlord.

Reducing the Section 24 impact

Options available now before the 2025/26 return:

• Salary sacrifice to bring salary below the higher-rate threshold (making rental income attract only 20% tax).
• Pension contributions to reduce adjusted net income.
• Transfer property to spouse if they are a basic-rate taxpayer (capital gains tax on transfer at market value unless a main home, consider IHT implications).
• Incorporate to a limited company (see Task 5).

Task 5: Consider limited company incorporation (if profit >£25,000)

The Section 24 restriction does not apply to corporate landlords. A limited company pays Corporation Tax (19–25% depending on profits) on net rental income after mortgage interest. For a higher-rate individual landlord paying 40% on the same income, the CT saving is significant.

When incorporation is likely to pay off:

• Rental profits above approximately £25,000/year (below this, accountancy and compliance costs often eat the saving).
• You reinvest rental profits rather than needing them as personal income immediately.
• You are building a portfolio (buying through the company avoids future S24 exposure entirely).
• You are prepared to pay professional costs: accounting, legal, incorporation, potential CGT/SDLT on transfer.

The transfer problem:

Moving an existing personally-owned property into a limited company is a disposal for CGT and SDLT purposes:

• CGT: market value minus acquisition cost × 18%/24% rate (or with BADR if applicable).
• SDLT: market value × standard SDLT rates + 5% surcharge.

For most landlords with modest portfolios, the transfer costs make retroactive incorporation unattractive. It works best when building a new portfolio via the company from scratch.

New purchases via a company also carry the 5% SDLT surcharge (increased from 3% in April 2025) — but this applies equally to individual purchasers, so it is a level playing field on new acquisitions.

SDLT reminder: 5% surcharge from April 2025

The Stamp Duty Land Tax additional homes surcharge increased from 3% to 5% with effect from 31 October 2024 (England and Northern Ireland). Scotland has its own Additional Dwelling Supplement (ADS) at 8%.

This affects the economics of expanding a portfolio. On a £250,000 BTL purchase:

Under the old 3% surcharge, total SDLT would have been £10,000. The increase of £5,000 per £250,000 property needs to factor into yield calculations.

Additional summer tasks (quick hits)

• Renew contents or buildings insurance — check your landlord policy covers void periods and accidental damage by tenants.
• Check EPC rating — minimum EPC E is required for new tenancies; proposed regulations may raise this to C in coming years. An early improvement avoids rushed upgrades later.
• Review your rent — if the tenancy is periodic, a Section 13 notice can raise rent with 2 months' notice. Check local market comparables.
• Check deposit protection — if a tenancy renewed or rolled onto a statutory periodic, the deposit must still be protected in a government-approved scheme.

Sources

• HMRC: Restricting finance cost relief for landlords (Section 24)
• HMRC: Self Assessment payments on account
• HSE: Gas Safety obligations for landlords
• gov.uk: Stamp Duty Land Tax on additional residential properties