Invasive species due diligence for commercial property in 2026
Acquisitions, refinancing and portfolio audits — when to commission a Phase 1 invasive species survey and what it costs.
Commercial property due diligence has caught up with the residential market on invasive species. By 2026 it is unusual to see an acquisition over £2m close without a Phase 1 invasive species survey on the data room.
When to commission
- At heads of terms — to inform price negotiation.
- Pre-exchange — most common timing, often as a condition of the lender drawdown.
- Portfolio refinancing — bulk survey across all secured assets.
- Post-acquisition asset management — to inform CAPEX planning.
What it covers
Whole-site walkover, mapping of every Schedule 9 and IAS-Order species, photographic record, written report with risk classification and indicative remediation cost. Phase 2 (intrusive investigation and management plan) follows where species are identified.
Indicative 2026 pricing
- Single industrial unit (≤2 acres): from £850 + VAT.
- Mid-size site (2–10 acres): £1,400–£3,500 + VAT.
- Portfolio audit (20–50 assets): £18,000–£42,000 + VAT.
Reviewed by
The survey team
PCA-certificated surveyors, Japanese Knotweed Elimination
PA1 / PA6A certificated surveyors who carry out the site visits, write the management plans and sign off the reports issued to lenders and solicitors.
Reviews the technical, legal and lender statements in this article.
What this page can't tell you
- Guidance is general. Identification, treatment choice and timescales can only be confirmed by a site visit — photographs alone are indicative.
- Lender and insurer requirements vary by institution and change over time. We state what is typically accepted, not what any named lender will accept on your case.
- Guarantee (IBG) eligibility depends on the plan chosen, the survey findings and the underwriter's acceptance. It is not automatic.
- Legal points summarise published law and guidance current at the review date. They are not legal advice.
Last reviewed · Questions on anything stated here: 07582 869979
Think you've found knotweed? Send us a photo.
Free written identification from a PCA-certificated surveyor — no obligation.
Free identification