TIMBER TREATMENT SPECIFICATION OPTIONS
The treatment requirements for Stratlam products are specified in AS/NZS 1604.5 “Specification for preservative treatment. Part 5: Glued laminated timber products.”
In order to meet the Services Classes outlined above, depending on where the Glulam structure is to be used, specifiers will need to select timber treatment levels based on the following:
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Hazard Class
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Service Class
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Exposure
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Specific Service Conditions
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Biological Hazard
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Typical uses
|
|
H1
|
1
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Inside, above ground
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Completely protected from the weather, well ventilated and protected from termites.
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Lyctid borers
|
Interior beams, staircases
|
|
H2
|
2
|
Inside, above ground
|
Protected from wetting. Nil leaching
|
Borers and termites
|
Interior beams, framing, staircases
|
|
H3
|
3
|
Outside, above ground
|
Subject to periodic moderate wetting and leaching.
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Moderate decay, borers and termites.
|
Exterior beams, posts
|
|
H4
|
3
|
Outside, in ground
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Subject to severe wetting and leaching.
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Severe decay, borers and termites
|
Light standards, building columns
|
Timber treatment options can be either CCA treatment (the requirement for H5 or H6 is rare and specific situations should be discussed with the manufacturer) or LOSP (up to H3). LOSP is an envelope treatment, and because of this, care must be taken when cutting or drilling post-treatment that the affected area is recoated with a suitable protective coating.
Specifiers should note that the Hazard Class definitions for New Zealand differ slightly to those listed above. Please refer to NZS 3640 “Chemical preservation of round and sawn timber” for further details.
Where treated Stratalam products are to be used in New Zealand the product must be treated to the retention requirements of the New Zealand Hazard Class and the penetration requirements of AS/NZS 1604.5.
