Standards & compliance
The NZ standards behind every dry-out
Structural drying isn't just running fans — it's returning a build to a documented, code-compliant dry state. Here are the standards we work to, and exactly what each one means for your build.
NZ moisture-content targets
The numbers materials must hit before lining, flooring or coating. We dry to these and document the result.
| Material | Target | Standard |
|---|---|---|
| Timber wall framing (radiata pine)Maximum at the time linings are fixed. Wetted framing must be dried back below this before any plasterboard goes on. | ≤ 18% MC | NZS 3604:2011 |
| Floor joists & bottom plates | ≤ 18% MC | NZS 3604:2011 |
| Roof framing | ≤ 18% MC | NZS 3604:2011 |
| Engineered timber (LVL) | ≤ 16% MC | NZS 3604:2011 |
| Plasterboard (GIB) liningNo elevated readings behind the board before stopping & painting. | Surface-dry / at equilibrium | Manufacturer + industry |
| Concrete slab (before floor coverings)Confirm the number against the specific floor-covering manufacturer — it varies by product. | In-situ RH per flooring datasheet | ASTM F2170 / product spec |
| Ambient relative humidity (drying zone) | < 50% RH | NZBC E3 / industry |
Standards, codes & legislation
Timber-framed buildings
The primary standard for timber framing in NZ residential construction. Sets the maximum moisture content for framing at the time linings are fixed — ≤ 18% MC for sawn pine, ≤ 16% for LVL.
What it means for you: This is the headline pass/fail on your build. Lining over framing above 18% MC is a Building Code breach and a weathertightness liability. We dry framing back to spec and document it before your lining trade starts.
External moisture
Buildings must keep external moisture — rain, groundwater — out of the structure. Where water has got in, remediation must restore E2 compliance.
What it means for you: Relevant after a storm, wrap failure or wind-driven rain on an open build. We dry the affected envelope and give you the readings to show the structure was returned to a compliant, dry state.
Internal moisture
Buildings must prevent moisture from internal sources — condensation, plumbing, wet trades — causing undue dampness or damage. The dried structure must meet E3 before reinstatement.
What it means for you: Wet trades (plaster, screed, paint) and slab water load the build with internal moisture. We drive the drying zone below ~50% RH so the next trade isn't working into damp.
Durability
Building elements must stay functional for set minimum periods — 15 years structural, 5 years non-structural. Moisture left in materials shortens that life.
What it means for you: Closing damp framing or laying over a wet slab compromises B2. Documented drying protects the durability you're signing off — and your liability tail.
Hazardous building materials
Governs materials that can harm health, including asbestos disturbed during work. Suspect materials must be identified before work proceeds.
What it means for you: On pre-1990 renovations, water can disturb asbestos-containing linings, textured ceilings and floor tiles. We stop and flag suspect ACM rather than disturb it — see asbestos below.
Residential property inspection
An inspection standard referenced in moisture assessment. Defines acceptable moisture benchmarks used by inspectors and assessors; readings above them trigger remediation.
What it means for you: The benchmark inspectors and BCAs use when assessing moisture. Our reporting speaks the same language, so sign-off is straightforward.
Professional water damage restoration
The global technical standard for structural drying methodology — assessment, extraction, dehumidification, monitoring and verification.
What it means for you: Our technicians work to S500 — the best-practice method NZ insurers and BCAs expect. It's why our drying is fast and our documentation holds up.
Professional mould remediation
The standard for assessing and remediating mould. Significant growth (generally > 1m²) requires containment and specialist remediation before drying continues.
What it means for you: If a renovation opens up established mould, we contain and address it to S520 before drying — not paint over it.
Health & Safety at Work Act
As a PCBU we must eliminate or minimise risk so far as reasonably practicable — electrical isolation in wet areas, slip management, confined-space procedure for cavity/subfloor work, safe manual handling.
What it means for you: We isolate circuits before entry, run all gear through RCDs, and follow confined-space procedure for subfloor and cavity drying — so our work doesn't create a hazard on your site.
HSW (Asbestos) Regulations
Pre-1990 buildings commonly contain asbestos. Before disturbing suspect materials a survey by a licensed assessor is required; removal needs a licensed (Class A/B) removalist.
What it means for you: On older renovations we don't disturb suspect ACM. We flag it, recommend a licensed survey, and dry around it — keeping you on the right side of WorkSafe.
Building Research Association of NZ
NZ's building research body. Its Good Practice Guides cover moisture management, ventilation and drying — the technical backbone behind our methods.
What it means for you: Our methods and target thresholds are BRANZ-aligned, which is the credibility your BCA and your client expect to see.
Our compliance checklist
What we tick off on every Christchurch drying job.
- Electrical isolation before entry to wet areasMandatoryHSWA 2015
- Asbestos check on pre-1990 buildings before disturbanceMandatoryAsbestos Regs 2016
- Moisture mapping before drying startsBest practiceIICRC S500
- Timber framing dried to ≤ 18% MC before liningMandatoryNZS 3604:2011
- Daily moisture & ambient monitoring logsBest practiceIICRC S500
- Mould PPE & containment where mould is presentMandatoryWorkSafe / HSWA
- Completion report before reinstatementBest practiceIICRC S500
See the gear behind it on our equipment & capability page, or read the drying guides.
FAQ
Standards & compliance FAQs
What moisture content does timber framing need to be before lining?
Under NZS 3604:2011, sawn pine framing must be at or below 18% moisture content when linings are fixed (16% for LVL). Lining over wetter framing is a Building Code breach and a weathertightness risk. We take pin-meter readings at marked locations and issue a signed report before your lining trade starts.
Which Building Code clauses apply to structural drying?
E2 (external moisture) and E3 (internal moisture) govern keeping water out and managing internal dampness; B2 (durability) is compromised if materials are closed up wet; F2 covers hazardous materials such as asbestos. Our drying and reporting are built around returning the structure to E2/E3 compliance and protecting B2 durability.
Are your methods BRANZ and IICRC aligned?
Yes. Our technicians work to IICRC S500 (the global structural-drying standard) and our target thresholds are BRANZ-aligned. That's the methodology and credibility your BCA, QS and insurer expect to see.
What about asbestos on older renovations?
Buildings before 1990 commonly contain asbestos in linings, textured ceilings and floor tiles. We don't disturb suspect material — we flag it and recommend a licensed survey under the Asbestos Regulations 2016, then dry around it. Disturbing ACM without a survey is a serious WorkSafe breach.
Do you provide documentation for insurers and the council?
Every job comes with moisture mapping, dated daily logs and a completion report confirming the structure reached target moisture before reinstatement — the evidence insurers, EQC and BCAs require, and what protects a claim from being reduced for failure to mitigate.
Got a build that needs drying?
Talk to the only Christchurch drying crew that quotes on your programme, not against it.