Roof Slate Headlap

Two layers 30 felt 19 overlap.

Roof slate headlap.

30 felt or comparable evaluation report required. If there is no headlap the roof will leak. Generally speaking 20degrees is the lowest advisable pitch for a slate roof depending on the size of the slates and how much that the roof is exposed to moderate weather conditions. Minimum recommended headlap mm unit 15 16 airfield approach business park flookburgh grange over sands cumbria la11 7ng england tel.

2 to less. 3 12 to less than 4 12. Headlap is essen tially what renders the roof water tight. When the head of a slate is overlapped by the slate two courses above it that s called headlap that s the critical overlap on a slate roof figure 2.

If there is no headlap the roof will leak. Headlap is what keeps the water from penetrating through the roof. Slates must overlap 3 inches on the side which is called sidelap and must overlap on the top which is called headlap. The primary aspects to be considered are.

Bs 5534 2014 is the code of practice for slating and tiling. Underlayments are installed on the roof deck prior to the installation of the slate roofing shingles. Lap ends 6 irc 4 2 horizontal. When slating with a shallow pitch a wide slate is highly recommended for maximum side lap or lateral lap side overlaps.

Headlap is what renders the roof water tight. A slate roof can last for a century and it is one of the major reasons that people choose this material over others. When the head of a slate is overlapped by the slate two courses above it that s called headlap that s the critical overlap on a slate roof figure 2. The steeper the slope the less water migration there will be.

In slate roofing water migration is controlled primarily by the angle of the roof s slope. Minimum headlap for fixing slates with nails or hooks the installation of a slate roof involves a number of aspects that must be considered in the design process. Type 90 mineral surfaced underlayment. Tile roof institute guidelines.

It describes not only the means of installing slates nailing or hook fixings but also the headlaps or lap required to ensure that the roof remains watertight even at pitches as low as 20 degrees. First calculate your roof pitch and then determine the inches required for sidelap and headlap. Most significant is the environment with the two main factors being exposure to wind and rain.