In short both. A Level 3 Survey (often referred to as a “Building Survey”) can be carried out on houses and flats. The key difference isn’t the property type—it’s the level of detail and the type of risk you want the survey to address.
RICS describes a Level 3 survey as the most thorough home survey option, covering the materials used in each part of the building, identifying defects, setting out remedial options, and commenting on future maintenance.
What changes between a house and a flat is what can realistically be inspected and where responsibility for repairs sits (individual owner vs freeholder/managing agent).
What a Level 3 Survey is designed to do (in plain English)
A Level 3 Survey is intended for situations where you need deeper clarity, for example because:
- the building is older, altered, unusual, or in poorer condition
- you want detailed guidance on defects and repair approach
- you’re planning major works or need stronger reassurance
RICS explains that Level 3 is more detailed than other survey levels and covers defect identification, remedial options, and future maintenance considerations.
Level 3 Surveys for houses: what your surveyor will focus on
With a house, the surveyor can usually inspect a wider range of elements within the same ownership boundary, so the report often gives you a very strong “whole building” picture.
A Level 3 Survey on a house typically places a lot of emphasis on:
1) The structure and building fabric
- roof coverings, chimneys, flashings and high-level details (from safe vantage points)
- external walls (brickwork/render/cladding), pointing, cracking and weathering
- internal walls/ceilings/floors for movement indicators, damp symptoms and distortion
2) Higher-risk concealed areas (where accessible)
RICS notes that concealed areas normally opened or used by occupants are inspected if it’s safe to do so.
In practice, this often means more attention to places like:
- roof spaces/lofts
- cellars/basements (where present)
- accessible hatches and voids that are part of normal occupation
3) Services in “normal operation” (not specialist tested)
RICS is clear that services aren’t formally tested, but they are observed in normal operation.
So you may see more commentary about what was observed during typical use (without it becoming an electrical or gas safety inspection).
4) Repair options and maintenance planning
This is a big reason people choose Level 3: it doesn’t just say “there’s an issue”, it’s geared toward explaining what it means, what your options are, and how it may affect future upkeep.
Level 3 Surveys for flats: yes—but the scope works differently
A Level 3 Survey can be extremely valuable for flats, but you need to understand the reality of leasehold ownership:
- You “own” the internal demise (and sometimes limited externals like a balcony).
- The structure and many externals are often the freeholder’s responsibility.
- Access to communal areas and roof spaces may be limited.
Even so, a Level 3 Survey can be particularly useful for flats where the risk profile is higher—such as period conversions, altered layouts, or signs of damp/movement.
What the surveyor will look at in a flat
A Level 3 Survey of a flat will still provide detailed commentary on the flat itself (internal condition, visible defects, ventilation/condensation risk, signs of movement, window condition where accessible), and it may include observations of relevant shared parts where accessible and within the scope of inspection.
RICS’ Level 3 description also notes that external wall systems are not inspected, and if the surveyor has concerns, further investigation should be recommended before you become legally committed to purchase.
That’s especially important for buyers of flats because the “big-ticket” building risks can sit in the wider envelope and communal responsibilities.
Services and common systems: what to expect
RICS’ Level 3 description indicates the surveyor can inspect certain building systems (within the identifiable boundary relevant to the subject property) but does not carry out specialist tests beyond normal operation.
In real-world terms, your report may still advise that you obtain:
- managing agent/freeholder documentation,
- maintenance history,
- and specialist inspections where risk is suspected.
When a Level 3 Survey makes most sense for a flat
A Level 3 Survey is often the best choice for a flat if:
The flat is a conversion or a period building
Conversion flats can hide structural changes, historic movement, and moisture issues that benefit from a more detailed survey approach.
The flat (or building) has been significantly altered
Knock-throughs, removed chimney breasts, reconfigured layouts, or loft-style conversions can increase uncertainty.
You’ve noticed red flags
Such as:
- damp staining/mould/musty odours
- cracking that looks more than cosmetic
- sloping floors or sticking doors/windows
- poor maintenance signs in communal areas
You’re planning major works
If you’re planning refurbishment, Level 3’s emphasis on defects, implications and maintenance can help you plan with fewer surprises.
When Level 2 may be enough (house or flat)
If the property is modern, conventional, and appears to be in reasonable condition, many buyers find Level 2 gives the right balance of detail and cost. The main reason to step up to Level 3 is when complexity or risk increases—because the extra detail becomes genuinely useful rather than just “more pages”.
The takeaway
- Level 3 Surveys are for both houses and flats.
- They’re most valuable where the property is older, altered, unusual, or showing warning signs.
- For flats, the scope has practical limits (especially around external wall systems), so a good Level 3 will also guide you toward the right follow-up enquiries and investigations before you commit.
Want help choosing the right survey for your purchase?
Email mail@howorth.uk or call 07794 400 212 and tell us whether you’re buying a flat or a house, the approximate age, and any concerns you’ve noticed (damp, cracking, roof condition, alterations). We’ll advise whether Level 2 is likely to be sufficient or whether Level 3 is the smarter choice.