Why SDLT matters for developers
Stamp Duty Land Tax (SDLT) on your site purchase is a significant upfront cost that directly affects your development appraisal. Getting the classification right — residential vs non-residential vs mixed-use — can save tens of thousands of pounds. Getting it wrong can result in unexpected tax bills or HMRC enquiries.
Non-residential rates (development land)
Pure development land — greenfield sites, brownfield sites without existing dwellings, and commercial buildings — attracts non-residential SDLT rates:
- 0% on the first £150,000
- 2% on £150,001–£250,000
- 5% above £250,000
On a £500,000 site, non-residential SDLT is approximately £14,500. The 3% surcharge for additional dwellings does not apply to non-residential purchases, even when purchased through an SPV.
Residential rates
If the development site includes an existing dwelling (even if you plan to demolish it), the purchase may be classified as residential for SDLT purposes. Residential rates are higher, and the 3% surcharge applies for SPV/company purchases.
On a £500,000 residential purchase through an SPV: approximately £27,500+ (including the 3% surcharge).
Mixed-use — potential savings
Properties with both residential and non-residential elements (e.g., shop with flat above, pub with accommodation, commercial unit with caretaker's flat) may qualify for mixed-use SDLT rates, which are the lower non-residential rates. This can save significant amounts on purchases that might otherwise be classified as residential.
Warning: HMRC has increased scrutiny of mixed-use claims. The non-residential element must be genuine and substantive — a token shed or garage used for storage may not qualify. Take specialist SDLT advice before claiming mixed-use treatment.
Impact on development finance
SDLT is a day-one cost that must be included in your development appraisal. Most development finance lenders expect the borrower to fund SDLT from equity (it's not typically included in the loan facility). A £15,000–£30,000 SDLT bill on top of your equity contribution can be significant — so get the classification right and budget accurately.
When you submit on Assesr, include the correct SDLT figure in your total project costs. The AI credit paper factors this into the financial appraisal and LTC calculation.