Timber posts/handrails/balusters are rotten
Listed under: timber and wood-based, timber, Section, barriers and balustrades, handrails, moisture, durability, rot
Cause
Inadequately treated timber
Repair
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remove affected timber, cutting well back from the area of visible rot. It is often better to replace entire handrails/balusters/posts rather than trying to cut out rotted sections. Where a joint is made in a handrail, it should be made over a support (see drawing)
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replacement handrails, balusters etc. (pinus radiata timber exposed to the exterior but not in ground contact) should be H3.2-treated. Timber should be at least SG8 (structural grade 8 for wet-in-service conditions) and SG6 for infill members
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handrails should be a minimum 90 x 45 mm, fixed with 4/ 100 x 3.75 nails to each structural post
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top and bottom rails should be a minimum 90 x 45 mm, fixed with 4/100 × 3.75 nails between or to inner or outer faces of structural posts
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nails should be hot-dipped galvanized steel at the minimum, and stainless steel with annular grooves in exposure zone D (i.e. coastal areas with salt in the atmosphere). Fixings should also be stainless steel where timber is treated with Copper Azole or Alkaline Copper Quaternary preservatives
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posts in ground contact must be H5-treated
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this is a good opportunity to bring the barrier up to meet current requirements if it does not. Barriers for residential decks must:
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be continuous where the fall height is over 1.0 m
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be at least 1.0 m high
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have openings that prevent a 100 mm diameter sphere passing through
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have less than 15 mm gaps in infill panels
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have the top of the barrier at least 760 mm above a fixed seat
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have no sharp edges or projections.