The short answer
Surface sampling takes a clear tape lift or a swab from a stain, a dusty contents item or a suspect surface and sends it to a laboratory for microscopy. It answers questions an air test can’t: is this discolouration mould, is it actively growing, and has a room’s contents been dusted with spores?
Who books this
- Stains that might be mould, dirt, soot or tannin bleed
- Contents, furniture and stock after a leak or flood
- Checking surfaces before and after works
Methods used
- Tape lift
- Swab
- Bulk material sample
- Direct microscopy
Growth versus settled spores
A surface can carry two very different things. Active growth means hyphae — the threadlike body of the mould — are present and the surface has had enough moisture to support it. Settled spores mean spores have landed from the air, which is normal at low levels and becomes significant when it is heavy or of a water-damage type. The ANSI/IICRC S520 standard, which many Australian contractors work to, draws a similar line between settled spores and actual growth.
Which method for which surface
Tape lift
Best on smooth, dry surfaces — painted walls, timber, furniture. Fast, and shows the structures under the microscope intact.
Swab
For rough, wet or textured surfaces where tape won’t hold, and for inside ducts and joinery.
Bulk sample
A small piece of material, such as a section of carpet underlay or plasterboard paper. Only taken with the owner’s permission.
Why surface results can’t be the whole story
A surface sample tells you about the square centimetre it came from. It does not measure what is in the air or behind the wall, and a clean tape lift from one wall says nothing about the next room. Surface results are reported against the location map from the inspection, so it is clear exactly what was sampled and what was not.
Questions people ask
Can you tell me what type of mould it is?
Laboratory microscopy generally identifies mould to genus level, such as Aspergillus/Penicillium-like, Cladosporium or Stachybotrys. Identification to species needs culturing, which is rarely needed to make a decision about a building.
Is black mould always Stachybotrys?
No. Many common moulds are dark in colour. Only laboratory examination can identify the genus, which is one of the main reasons to take a surface sample.
References
- [1]ANSI/IICRC S520 Standard for Professional Mold Remediation (4th ed., 2024) — Institute of Inspection, Cleaning and Restoration Certification
- [2]Mould after a disaster fact sheet — Queensland Health
Checked against these references on 2 November 2026.