Aerial view of a UK commercial industrial estate

Research · Paper 01 · August 2026

What a structural survey establishes

The phrase carries no protected meaning in the United Kingdom. Anyone may use it, and it is used to describe several different pieces of work that answer materially different questions. This paper sets out what each one establishes, what it does not, and how to specify an appraisal when load is being added to a roof.

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Phrase in common use across the industry. “Structural survey” is not a protected term and carries no single defined scope.

Distinct pieces of work commonly described by that one phrase, each answering a different question about a building.

Question that matters when load is added: can the existing structure carry it, and on what basis is that concluded?

01 · The problem

One phrase, several different pieces of work

A buyer asking for a structural survey and a supplier quoting for one are frequently describing different work. Neither party is being dishonest. The phrase simply has no fixed meaning, and the market has attached it to at least four distinct products.

What is protected, and what is notIndividual professional titles are protected. Chartered status is regulated by the relevant institution, and the RICS designations are held by members of that body. The phrase “structural survey” is not protected, is not defined in statute, and may be used by anyone to describe anything.

The consequence is a specification failure, not a competence failure

Most disputes we see over the adequacy of a survey are not about whether the work was carried out properly. They are about whether the work carried out was the work the buyer believed they had commissioned. A visual condition inspection performed correctly is still the wrong instrument for establishing whether a roof can carry an additional load, and a report that answers the first question cannot be criticised for failing to answer the second if the second was never asked.

It surfaces at the point of reliance

The gap is rarely noticed at instruction. It is noticed when a third party — a lender, an insurer, a certification body or a purchaser’s adviser — asks the report to support a conclusion it was never scoped to reach. At that point the building has usually already been committed to.

Figure 1

Only one of these answers the load question

Schematic, not data. The distinction is one of scope rather than rigour. A condition inspection carried out impeccably still does not produce a load capacity, because producing one was never within what it was commissioned to do.

02 · The test

Only one of these answers the load question

Several different pieces of work travel under the same phrase. They are not interchangeable, and the difference is not a matter of quality or diligence. It is a matter of what each is scoped to establish. Where load is being added to a roof, there is one question that has to be answered, and most of these are not built to answer it.

Table 1. Work commonly described as a structural survey, tested against the question that matters when load is added.
Form of work	The question it answers	Does it establish whether the roof can carry a new load?
Condition inspection	What is the present visible condition of the fabric, and what maintenance does it need?	No. It records what is there. It performs no calculation
Building survey Home Survey Level 3 and equivalents	What is the condition in detail, and what caused it?	No. It is a condition instrument, and it is scoped to a dwelling rather than to added load on a commercial roof
Roof condition assessment	What is the condition of the covering, fixings, flashings, rooflights and drainage, and how long has it left?	No, and it is not scoped to. It answers the other half of the question — how long the covering lasts under whatever is put on it
Structural appraisal for added load	Can this structure carry this defined new load, under the governing combination of actions?	Yes. It is the only one of these that does, and it is the work of a structural engineer

A condition instrument records. An appraisal calculates against a defined load case and reaches a conclusion that can be relied upon. That is not a ranking of rigour — a condition inspection carried out impeccably still does not produce a load capacity, because producing one was never within its scope.

03 · What a roof taking new load actually needs

Two questions, and both have to be answered

Adding load to an existing roof raises two separate enquiries. They are frequently confused, and answering one is routinely mistaken for answering both.

Can the structure carry it?

A structural appraisal against a defined load case, with actions combined under BS EN 1990 and the governing case identified. This is calculation, and it concludes. It is carried out by a structural engineer because that is who is qualified to reach and sign the conclusion.

How long will the covering last underneath it?

A roof condition assessment establishing the state of the covering, its fixings and its drainage, and what remains of its service life. This matters because whatever is mounted on a roof usually outlives the covering beneath it, and replacing a covering with an array or plant sitting on it is a different and far more expensive exercise than replacing it beforehand. Across our dataset, 82% of roofs assessed carried defects capable of affecting long-term waterproofing performance.

A roof can pass the first and fail the second

That is the case a single instrument will always miss. A structure with ample capacity under a covering with five years left is a scheme that works on paper and creates a problem in year five. Both questions have to be put, and putting only the structural one is the more common error because it is the one a certification process is more likely to prompt.

Which is why we carry out both

Solar Surveys undertakes on-site structural surveys and roof condition assessments, individually or in a single attendance. The structural arrangement is recorded from below and the covering from above, by the same engineering team, so the two answers are produced against the same building on the same day rather than assembled from two exercises that never met.

04 · Requirements

What an appraisal for added load has to contain

Where load is being added to an existing roof — an array, plant, screening, a safety system, a mezzanine — four things have to be present for the conclusion to be capable of being relied upon.

1. The structural arrangement, recorded rather than assumed

Member sizes, spans, support centres and the fixings, taken from the building as it stands. On a large share of commercial stock there is no original design information, and where drawings exist they frequently predate decades of alteration. An appraisal that assumes an arrangement is assessing a building that may not exist.

2. A defined load case, not a weight

The added load is rarely the governing consideration. Actions are combined under BS EN 1990, with imposed actions to BS EN 1991-1-1, snow to BS EN 1991-1-3, and wind to BS EN 1991-1-4 with the UK National Annex. For a rooftop array, uplift derived using BRE Digest 489 frequently governs rather than dead load — which is why a calculation based on panel weight alone answers the wrong question.

3. A conclusion, stated plainly

Adequate, adequate subject to defined changes, or not adequate — and where not adequate, what would be required to make it so. A report that describes without concluding transfers the decision back to a party who is not qualified to make it.

4. A named signatory and a date

Signed by a qualified structural engineer, dated, and identifying what was and was not inspected. Reliance depends on somebody having taken responsibility for the conclusion. An unsigned report is a document, not an appraisal.

Interior structural arrangement of a UK commercial roof recorded during survey

05 · Specifying it

How to ask for the right thing

Because the phrase is not defined, the instruction has to carry the definition. Four lines are sufficient, and they remove almost all of the ambiguity that causes disputes later.

State the load being added. Its nature, its magnitude, and where on the roof it will sit. An appraisal cannot be carried out against an undefined load.

State the standards required. The Eurocodes and their UK National Annexes, and where applicable BRE Digest 489 for array uplift.

State who must sign it. A qualified structural engineer, named, with the report dated.

State who will rely on it. If a lender, insurer, certification body or purchaser will read the report, say so at instruction rather than after issue.

A specification of four lines converts an ambiguous phrase into a defined piece of work, and it costs nothing.

06 · Where certification schemes sit

A scheme requirement is a floor, not a definition

Certification schemes prescribe requirements within their own scope. They do not define what a structural survey is, and their scope is narrower than the range of situations in which load is added to a roof.

The scope boundary is the point most often missed

Within the Microgeneration Certification Scheme, MIS 3002 sets requirements for solar photovoltaic installations and its scope stops at 50kWp DC. Above that threshold the scheme does not apply. Building Regulations continue to apply to the alteration, as they would to any alteration, but no scheme-level prescribed check applies. The engineering question is unchanged either side of the boundary; only the prescribed process changes.

And the same applies to loads that are not photovoltaic at all

Plant, condensers, screening, mansafe systems, green roofs, signage and mezzanines all add load to structures that were not designed for them, and none of them falls within a solar certification scheme. The appraisal required is the same appraisal. Only the reason for it differs.

How Solar Surveys approaches this

We are engaged to answer the load question, not to describe the roof

Everything above is the reason Solar Surveys exists in the form it does. The market is full of work that records a roof accurately and then stops short of the one thing a client adding load actually needs: a conclusion. We were set up to produce the conclusion.

We calculate, and then we conclude

Our reports do not hand back a description and leave the decision with somebody not qualified to take it. Actions are combined under BS EN 1990, the governing case is identified, and the report states whether the structure can carry the proposed load. That is the deliverable.

Both questions, in one attendance

The structural arrangement is recorded from below and the covering from above, on the same visit, by the same engineering team. Two answers about the same building on the same day, rather than two exercises that never met.

Signed by a structural engineer, every time

Every roof we assess is reviewed and signed by a qualified structural engineer. That is our own standard. We hold it whether or not a certification scheme asks for it, because the alternative is a conclusion nobody is qualified to stand behind.

A description tells you what the roof looks like. An appraisal tells you what it can carry. Only one of those lets you commit to a layout.

On-Site Structural Surveys How to Specify One

Solar Surveys Ltd · structural surveys and roof condition assessments for commercial solar PV across the UK · £5m professional indemnity cover in force.

07 · Basis and limitations

How this paper was prepared

Basis: This paper is an analysis of published standards, professional practice and the terms in common commercial use. It is not derived from survey data and reports no statistics.
Standards referenced: BS EN 1990; BS EN 1991-1-1; BS EN 1991-1-3; BS EN 1991-1-4 with the UK National Annex; BRE Digest 489; MCS MIS 3002 Issue 6.0.
Scope: Commercial and industrial buildings in the United Kingdom where load is being added to an existing roof structure.

What this paper is not: It is not legal advice, and it is not a statement of any professional body’s position. Where a scheme, insurer or regulator sets a specific requirement, that requirement governs.
Scopes vary: Table 1 describes forms of work as commonly encountered. Any practice may scope its work differently, and any of these instruments may be extended by agreement.
No comparative claim: Nothing here is a statement about the competence of any individual or firm. The subject is the specification of work, not the people who carry it out.

08 · Citation

Cite this paper

Suggested citation

Raihan, S. (2026) What a Structural Survey Establishes, and What It Does Not. Solar Surveys Research, Paper 01. Solar Surveys Ltd. Available at: https://solarsurveys.co.uk/research/what-a-structural-survey-establishes

© 2026 Solar Surveys Ltd. All rights reserved. Journalists, researchers, industry bodies and educators may quote from this paper with attribution and a link, and no permission is needed to do so. Republication in full, adaptation, redistribution or any commercial use requires written permission — ask, and it is normally given. Writing about this and want something clarified, or a breakdown we have not published? Ask. We would rather it was reported correctly than quickly.

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