Fence rails warped/twisted

Cause

Timber movement

Repair

  • where the twisting is minor and the timber rails can be straightened out with force, install extra fixings at the posts. As a minimum protection, use hot-dip galvanized nails, or stainless steel in very corrosive environments (close to the sea or in a geothermal area). Nails with an annular grooved shank will have better holding power. Where nails are close, stagger the position to reduce the risk of timber splitting
  • another option is to use hot-dip galvanized or stainless steel bolts or ‘tek’ screws to fasten rails to posts. Use a G or F clamp to adjust palings and rails so they are flat against the rail or post, then screw tight. Using a nail or screw to pull the board back is not likely to be successful – a clamp gives better control when straightening and flattening timber. Screws/bolts should then be applied to hold the timber in the now flat position
  • where rails cannot be straightened with pressure and the appearance is visually unacceptable, replace them. H3.2-treated radiata pine rails are readily available. As a minimum protection, fix with hot-dip galvanized nails with an annular grooved shank, or stainless steel in very corrosive environments (close to the sea or in a geothermal area)
  • dark-coloured finishes on timber attract heat from the sun and resulting temperature extremes can cause unwanted changes in timber shape over time. Using lighter-coloured finishes (or no finish at all) will reduce the risk of movement

Cause

Insufficient support

Repair

  • for minor twisting, follow repair above
  • where the posts are too far apart, install intermediate posts or replace existing posts with new at more effective distances. For a strong fence, posts should be no more than 1800 mm apart. For fences up to 1800 mmm high, ensure the holes are at least 750 mm deep and set in concrete