Rusty nail fixings on exterior walls

Cause

Heads of fixings are not protected by putty where punched and stopped 

Repair

  • remove corrosion by sanding or brushing with a stiff bristle brush. Apply a proprietary rust killer then punch nails at least 5 mm into the timber cladding. Prime punch holes and when dry, stop with putty or exterior grade filler. Sand and repaint with at least 2 coats of quality acrylic paint

  • where nails stand proud of the timber surface, try to extract them and replace with stainless steel annular grooved nails or hot dip galvanized nails. Punch and finish as above

  • where nails are badly corroded or broken, punch them completely through the weatherboard. Drive stainless steel annular grooved nails or hot dip galvanized nails through the same hole but slanting upwards. Punch and finish as above

Cause

Incorrect fixing type used for environmental conditions, cladding type or finish 

Repair

  • replace existing fixings with suitable fixings for the conditions: select hot-dip galvanised, annular grooved stainless steel or silicone bronze. The key factor is the type of exposure the fixings will face – fixings in seaspray and geothermal areas need to be more durable, for example stainless steel 

Cause

Rust was not cleaned off fixings before re-stopping/repainting

Repair

  • remove corrosion by sanding or brushing with a stiff bristle brush. Apply a proprietary rust killer then punch nails at least 5 mm into the timber cladding. Prime punch holes and when dry, stop with putty or exterior grade filler. Sand and repaint with at least 2 coats of quality acrylic paint

Cause

Inadequate paint finish to provide protection

Repair

  • remove corrosion by sanding or brushing with a stiff bristle brush. Apply a proprietary rust killer then punch nails at least 5 mm into the timber cladding. Prime punch holes and when dry, stop with putty or exterior grade filler. Sand and repaint with at least 2 coats of quality acrylic paint

Cause

Acidic leachate from cedar or H4-treated timber (containing copper-based preservatives)

Repair

  • galvanized steel nails should not be used in these circumstances. Instead, use annular grooved stainless steel or silicon bronze nails

Cause

Corrosion protection of fixings (such as zinc) was damaged during installation

Repair

  • remove corrosion by sanding or brushing with a stiff bristle brush. Apply a proprietary rust killer then punch nails at least 5 mm into the timber cladding. Prime punch holes and when dry, stop with putty or exterior grade filler. Sand and repaint with at least 2 coats of quality acrylic paint