Missing timber weatherboard(s)

Causes

Unfinished maintenance or renovation work, lack of maintenance

Boards rotted or split and have fallen out

Listed under: Exterior, finishes, timber and wood-based, paint, timber, cladding, walls, durability, rot, wall cladding, painted timber weatherboards

Cause

Unfinished maintenance or renovation work, lack of maintenance

Repair

  • check that the support framing is sound and dry. Where there is extensive moisture or mould inside a wall, this will need to be addressed first. Consult a registered building surveyor if necessary

  • source matching weatherboards – where the exact profile is not commercially available it can be ordered as a one-off. Radiata pine weatherboards should be treated to a minimum H3.1 if they are to be paint finished on all surfaces or minimum H3.2 if stained or clear-finished

  • measure replacement boards to ensure that butt joints are located at studs and staggered so that running joints do not occur one above the other

  • if necessary, make clean and straight ends to existing fixed boards with an electric multi-tool to allow a tight repair. After cutting existing or replacement boards, apply primer to all cut ends and the backs and edges of all replacement boards

  • check existing wall underlay and replace if necessary by inserting new underlay under the existing underlay at the top and lapping over the existing at the bottom. Underlay provides an important drainage path for water that gets behind the cladding. Ensure existing and new underlay is not damaged during the work

  • start from the highest board and work down. Insert wedges or spacers under weatherboards that will overlap the board(s) being repaired (see drawing)

  • where installing new rustic profile boards, ensure 2 mm expansion gaps between the horizontal edges of the laps of successive boards. Plane the top edge of new boards as required, treating with a timber preservative

  • when replacing small sections, apply two-part epoxy adhesive to the edges of the existing and new sections, slip the new section of weatherboard into position and fix with a single nail into the stud. Ensure you stay within the open or working time of the epoxy

  • paint with at least two coats of good quality acrylic paint

  • there are further details in the BRANZ book Good Repair Guide Horizontal timber weatherboards

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Cause

Boards rotted or split and have fallen out

Repair

  • the guidance in the first repair generally applies, but where rot is present the source of moisture causing the rot must be fully understood and addressed as part of the work. Consult a registered building surveyor if necessary

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