The overlaps should be 150mm minimum and the only fixings should be a few copper nails under the overlaps.
How to build a lead roof valley.
The roofing nails are fine so long as the lead of the roof valley is intact but once it starts to crack or fracture due to water pressure corrosion or other damage the nail provides a space for water to run into the home.
But it doesn t have to be.
The three methods to shingle a roof valley.
A roof valley is basically a gutter set between two meeting pitched roofs.
This should be laid in two 1500mm lengths with a third length at the top.
Installation procedures differ depending on the roof type and materials used.
In these circumstances it may be possible to just leave the existing valley base in place and replace only the cement.
450mm wide code 4 lead should be used turned back at the edges.
Check the entire roof valley carefully to locate the source of these problems.
Framing a complex roof is one of the trickiest parts of home building.
Roof valleys are a frequent source of leaks in older houses.
This recommendation includes iko s premium shingles.
When deciding how to shingle a roof valley you will need to consider your materials the climate and the desired look of the roof.
Iko recommends that you install architectural shingles with the open valley method for the best roof performance.
To replace a 4metre long zinc or swept valley on a slated or tiled roof with a nice new lead one.
If you begin with accurate as built measurements and use a construction calculator to do the math you can cut all of the rafters for most roofs on the ground in just one shot.
It is therefore worth asking the valley manufacturer for guidance on this.
Preformed grp valleys in many ways the roof construction for a pre formed grp valley is the same as that for a lead lined valley.
There are occasions when a roof valley is in good condition but the cement holding the tiles in place has washed out or crumbled.