It’s best to call a professional to fix a leaking roof. Too many people sustain lifelong injuries from falling off a roof.

If you’re the gung-ho sort who’ll go up there anyway, there are a few basic rules to observe.

  • Always wear well-fitting shoes with a good grip and go up there only in dry weather.
  • Follow ladder safety (see ‘Ladder safety’ under ‘Using tools correctly’ in the Contents List of this website).
  • If it’s an iron roof, walk along the rows of nails. This is where the purlins are (wooden or steel supports under the iron). If you walk in the gaps between, you’ll dent and damage the corrugations.
  • If it’s a tiled roof, walk on the overlap of the tiles where there is most support.

Iron

On a corrugated iron roof all the nails are lined up on the top of the corrugations. This is where they are least likely to cause leaks, as the water runs down the roof in the base of the corrugations. If you hammer a nail in anywhere other than along the lines where the purlins are, you’ll hammer into air and cause a leak. Roofing nails are specially designed to seal around the hole they create. Never use an ordinary nail on an iron roof.

Check for nails that have popped up. They tend to do this sometimes in very hot weather and, when it rains, will allow water to track down their shafts into the rafters. Sometimes the nail causing the problem will be quite distant from the spot in the ceiling where you noticed the leak. This is because the water has tracked down and along the woodwork in the roof cavity. Check all nails. Hammer them in place. If necessary apply some UV-resistant silicone under or around the nail to aid the seal.

If you need to pull a nail out to replace it, always pull it straight upwards. If you pull it sideways you could tear the iron, which will make it hard to seal over the wide hole with a new nail. If the head has pulled from the nail (which often happens with very old lead-head nails) you can hammer a new nail in bang up against the old nail. The new head should cover the shaft of the old nail and create a seal. Silicone under the nail head can help with this.

Tiles

You might be able to repair a cracked tile with a special filler from your plumbers’ supplier, but if you need to find a new tile be careful as there are all sorts of patterns and some are shorter or longer than others. Make sure you attempt a job like this on a fine, windless day when you can cover the hole with a piece of weighted plastic and spend the morning searching for the right tile.