Reporting rental income to HM Revenue & Customs requires completing supplementary schedule SA105 as part of your annual Self Assessment. Property taxation in the UK is governed by Part 3 of the Income Tax (Trading and Other Income) Act 2005 (ITTOIA 2005), as substantially amended by Section 24 of the Finance (No. 2) Act 2015.
Managing a property business requires strict adherence to statutory accounting boundaries, particularly regarding mortgage finance, repairs, and capital enhancements.
The Section 24 Finance Cost Restriction Explained
The single most impactful statutory rule affecting individual residential landlords is Section 24 (enacted in Section 24 of the Finance (No. 2) Act 2015, codified in sections 272A and 274A of ITTOIA 2005).
How Section 24 Works in Practice:
- Zero deduction from profit: You can no longer deduct mortgage interest, mortgage arrangement fees, or loan interest from gross rental receipts when calculating taxable rental profit.
- Artificial profit inflation: Your taxable income is calculated before finance costs. This can artificially push your total adjusted net income into the 40% Higher Rate band, trigger the loss of your Personal Allowance (over £100,000), or trigger the High Income Child Benefit Charge (over £60,000).
- The 20% Tax Reduction: In place of a deduction, HMRC provides a tax credit equal to 20% of the lowest of:
- Your total finance costs for the year.
- The property business profits for the tax year.
- Your total adjusted net income that exceeds the Personal Allowance.
Note: Section 24 applies strictly to individual and partnership landlords owning residential properties. It does not apply to commercial properties or properties held within Limited Companies (SPVs).
Allowable Repairs vs. Disallowed Capital Improvements
Under Section 272 ITTOIA 2005, deductions for property expenditure follow statutory trading expense principles. The boundary between revenue repairs and capital improvements is heavily audited by HMRC:
| Category | Statutory Tax Treatment | Examples |
|---|---|---|
| Revenue Repairs | Deductible 100% against current year rental profits | Replacing damaged roof tiles, interior redecorating, servicing boilers, replacing rotten floorboards |
| Technological Updates | Allowable as revenue repairs under HMRC concession | Replacing single-glazed windows with standard modern double-glazed units (acknowledged as like-for-like modern equivalent) |
| Capital Enhancements | Disallowed against income tax; added to CGT base cost | Adding an extension, loft conversion, conservatory, changing room layouts |
| Replacement of Domestic Items | Deductible under s311A ITTOIA 2005 (RDIR) | Replacing an old sofa, washing machine, or fridge with a modern equivalent for the tenant |
The "Initial Repair" Rule
Under established case law (Law Shipping Co Ltd v CIR and Odeon Associated Theatres Ltd v Jones), if you acquire a dilapidated property and undertake major renovations to make it tenantable, those initial costs are treated as capital expenditure rather than deductible revenue repairs.
Property Business Pooling & The £1,000 Property Allowance
Under UK statute, all UK residential properties owned by the same individual constitute a single composite UK Property Business.
- Profits and losses from multiple properties pool together automatically.
- A loss on one property offsets profits on another in the same tax year.
- Remaining net property business losses cannot be set against employment or trading income; they must be carried forward to offset future UK property business profits.
The £1,000 Property Allowance
Under Section 783B ITTOIA 2005, if your gross rental receipts are £1,000 or less, you are completely exempt from tax and reporting. If receipts exceed £1,000, you can elect to deduct the flat £1,000 property allowance instead of calculating actual expenses.
Abolition of the Furnished Holiday Lettings (FHL) Regime
From April 2025, the historic statutory distinction between standard Buy-to-Let (BTL) and Furnished Holiday Lettings (FHL) was abolished. Short-term holiday lets no longer qualify for:
- Full deduction of mortgage interest.
- Capital allowances on furniture and fixtures.
- Business Asset Disposal Relief (BADR) upon property sale.
All residential accommodation now falls under the unified SA105 statutory regime.
How ac-co Simplifies SA105 Landlord Filing
Managing landlord receipts, mortgage statements, and tenancy expenses through ac-co eliminates compliance friction:
- Separates capital improvements from allowable revenue repairs automatically.
- Computes the exact Section 24 20% tax reduction and carries forward unused finance costs.
- Aggregates income across single let, HMO, and multi-unit portfolios into a compliant SA105 schedule.
- Files seamlessly with HMRC alongside your SA100 with full digital audit evidence.