Consultants advising on commercial property - sustainability leads, building surveyors, M&E engineers, transaction advisers - increasingly field questions about rooftop solar. The client wants a view before capital is committed: Is this roof worth pursuing? Answering that question credibly requires more than a napkin calculation. It requires irradiance, financials, and engineering screening on wind, structure, grid, and planning.
Stage1Energy provides that analysis as a fixed-fee site assessment report - an independent solar feasibility assessment rather than an installer-led proposal. This article explains how consultants use it, what the four engineering flags deliver, and how feasibility fits your advisory workflow.
The question consultants are asked
Landlords and asset managers typically want to know:
- Will solar pay back within their investment horizon?
- Can the roof physically host an array without reinforcement or mounting problems?
- Will the grid accept the export, and how long will connection take?
- Does planning require a full application or permitted development?
- What is the verdict - pursue, pursue with conditions, or deprioritise?
Installer quotes answer cost and capacity but rarely provide independent financial modelling, sourced workings, or structured engineering screening. Spreadsheet models built in-house lack consistency across sites and portfolios. Consultants need a repeatable, defensible output they can present without overclaiming.
Commercial solar feasibility fills that gap: a 29-page report per site, reviewed before release, with a written verdict and four engineering flags.
What the report gives advisers
Each site assessment includes:
- Verdict - clear pursue / conditional / deprioritise recommendation with rationale.
- Layout - panel zones on the actual roof from satellite geometry.
- Generation - annual and monthly profile with loss assumptions stated.
- Financials - 25-year cashflow, NPV, IRR, payback, and scenario optimisation.
- Four engineering flags - wind, structural, DNO, planning - with risk levels and named next steps.
- Sourced workings - formula, result, and source for material figures in the PDF.
The example report is a real assessment published so you can judge depth before engaging. Our methodology explains our approach; every assumption is recorded in the report.
For a first pass, join the waiting list to register interest for the same full report standard - financials and engineering flags included. Useful for portfolio triage before committing further sites.
Engineering flags - what consultants can rely on
The four flags are the engineering section that technical reviewers and investment committees expect:
| Flag | Basis | Typical next step |
|---|---|---|
| Wind uplift | Uplift screening - P90 wind speed, height, roof zone | Get mounting supplier calculation before you budget |
| Structural load | Indicative dead-load triage - excludes structure self-weight, wind, snow | Structural engineer confirmation before design |
| DNO | Preliminary G98/G99 route by capacity | Confirm phase, export limiting and fuse rating with DNO |
| Planning | TCP(GPDO) 2015 Class A/J - indicative | Verify with local planning authority |
Each flag is screening, not sign-off. The report names what to verify and when - it does not replace structural engineers, DNOs, or planning authorities. That distinction protects advisers from overclaiming.
Deep dives: engineering flags overview, G98/G99, structural screening, wind loading, permitted development, DNO application.
Workflow for portfolio advisers
Consultants screening multiple sites - landlord portfolios, transaction due diligence, sustainability roadmaps - benefit from consistent sequencing:
- Triage - join the waiting list for one building per request.
- Deep dive - full report on shortlisted roofs once capacity opens.
- Board paper - report verdict and flags feed the investment case; workings support technical appendix.
- Handoff - named next steps on each flag guide survey commissioning: structural engineer, DNO application, planning verification.
- Installer tender - layout and capacity from the report inform RFP scope.
This sequence matters: a structural survey costs £2,000–£5,000 whether the roof works or not. Screening first means that spend only lands where it can pay back - and avoids commissioning surveys on roofs that fail on DNO or financial grounds. It also avoids presenting financial-only analysis that collapses when engineering blockers surface.
Liability and limits - stating them clearly
Consultants rightly worry about liability on solar advice. Stage1Energy reports are early-stage feasibility:
- Modelled generation has been compared against twelve months of metered output from operating commercial rooftop PV.
- Engineering flags name next steps; they do not certify compliance.
- Not design, not procurement, not construction documents.
- Engagement terms and the report Important Notice section state limits explicitly.
Your client still needs structural engineer sign-off, DNO approval, and planning confirmation where required. The report tells them whether those steps are worth ordering - which is a different and earlier question.
White-label and partner use
Firms advising at volume - portfolio landlords, sustainability consultancies, M&E practices - can enquire about partner and white-label arrangements via for partners. The underlying analysis, flags, and workings remain consistent; delivery can align with your client reporting standards.
Whether branded Stage1Energy or white-label, the output standard is the same: board-ready, sourced, reviewed before release.
When to recommend feasibility vs other routes
Recommend a feasibility report when:
- The client needs an independent view before installer engagement.
- Multiple sites require consistent screening and ranking.
- A board or investment committee expects sourced financial and engineering analysis.
- The adviser needs defensible output without building solar models in-house.
A full structural assessment or DNO application comes after feasibility confirms the roof is worth pursuing - not before.
Pricing and turnaround
- Waiting-list assessment - register interest for a verdict with layout and monthly generation when capacity opens.
- Full site assessment - report with four flags, financials, workings; five working days from confirmed inputs once booked.
- Portfolios - same standard per site; batches scheduled accordingly.
See waiting list for detail. Every report is reviewed before release; if it does not meet the stated standard - a clear pursue, pursue with conditions, or park recommendation with evidence and named next steps - it is reworked free.
For advisers packaging the answer
Your client does not need another generic solar brochure. They need a clear verdict on their roof - with engineering flags that name what to verify, financials that stack up under scrutiny, and workings that survive technical review.
That is what commercial solar feasibility delivers. Start with the example report, then join the waiting list.