H1.2 Treated Framing

What the H1.2 mark does - and does not - tell you

MBIE's framing-treatment material and CodeHub resources should be read with the current consent documents and producer information. Public summaries explain the framework; they do not reproduce every requirement of a cited standard.

Receiving H1.2 framing on site

1. Compare species, H1.2 identification, structural grade, dimensions and lengths with the purchase order.
2. Keep packet labels and photograph representative end or face brands before timber is distributed.
3. Separate damaged, excessively distorted or incorrectly marked pieces.
4. Store packs level, supported off the ground and protected while allowing appropriate ventilation.
5. Check moisture and close-in requirements under the project's current documents before lining.

Cuts, holes and substitutions need a record

Service holes, notches and cut ends can affect both treatment envelope and structural performance. Follow producer guidance and the framing design. A brush-on end-seal product is not a universal repair for an incorrectly treated member, and a carpenter should not invent a structural notch because the timber is treated.

If a merchant proposes H1.2 timber of another species, grade, size or preservative system, treat each changed attribute as a separate substitution. Obtain designer or building professional review where it affects the consented design.

Where H1.2 stops

H1.2 framing is for protected applications, not decks, exterior pergolas, ground-contact posts or retaining walls. Temporary wetting during construction also does not turn an interior product into an exterior one. Manage exposure and drying rather than relying on the treatment label as insurance.

• Deck framing commonly moves into H3.2 above-ground treatment and still needs structural design.
• Fence posts embedded in soil are commonly purchased as H4 products.
• Severe retaining applications may call for H5 product within an engineered system.
• Untreated or differently treated framing may be acceptable only where the current compliance pathway explicitly permits it.

Moisture is a construction-stage decision

H1.2 treatment does not set the moisture content at which framing may be lined. Rain exposure, pack storage, building enclosure and drying conditions influence the reading. Follow the consent documents, producer requirements and the building professional responsible for close-in. Test representative locations with an appropriate calibrated meter and record results where the project requires them.

Wet framing can move as it dries, and enclosing excess moisture can affect linings, insulation and indoor conditions. Do not use a dry-looking surface as proof. Conversely, do not reject treatment simply because timber arrived with moisture from the production process; verify the product and manage it under the project programme.

• Keep packs off soil and standing water.
• Cover the top while permitting ventilation appropriate to the product.
• Do not wrap wet timber so tightly that drying is prevented.
• Recheck after plumbing leaks or prolonged weather exposure.

Common site disputes resolved by documentation

Photograph labels before packs are broken. Link those images to the delivery docket and lot where possible. This small record is much easier to use than trying to identify unmarked framing after walls are closed.