A handy little guide to help make fixing fibre cement slates as easy as 1, 2, 3…
One of the areas most affected by the changes to BS 5534:2014 was fixing. As this is such a central part of the new Standard it’s important to get it right, especially on eaves and verges. With that in mind the team at Cembrit have supplied this handy little guide to ensuring your fibre cement slates are fixed to perfection.
Use a tilting fillet to make sure the underlay is supported behind the fascia so it doesn’t sag between the rafter feet. The underlays finish by hanging into the gutter, so that any moisture on the underlay drains into the gutter. Eaves should not be sprocketed, as this will affect fitting of the disc rivet at the tail of the eaves’ course.
You need three courses of slates at the eaves. The first under eaves course is cut and drilled and head nailed to the length of the batten gauge. Eave overhangs should be 50-55mm for 100mm gutters. Locate the centre point of the eaves and centre the first under eaves slate. Lay the first full slate over the top of this under eaves slate and cut the slates on both verges to the same width. Work towards both verges with the remaining under eaves slates.
Cut the second under eaves course from the same slate as the first course. Its length is the batten gauge, plus the slate headlap. This second under eaves slate provides the double lap for the next but one full course of slates. Install it to cover half the width of the first under eaves slate, allowing the shank of the tail rivet for the first full course of slates to pass between adjacent second slates, which oversails the fascia 50-55mm.
Nail the first full course of slates to the second batten so that the tail rivet passes between the two second under eaves slates and protrudes through the hole in the tail of the full slate. Ensure the first full course of slates oversails the gutter by 50-55mm. The tails of all three courses of slate should align and overhang the gutter.
To provide the correct bond, make sure the verge slate on alternate courses is a slate and a half width cut from a double slate. These verge slates need pre-drilled holes for three nail and two rivet fixings, and an extra hole to allow the tail rivet for the course above to pass through the slate and a half. The next single verge slate requires an additional hole for the tail rivet of the subsequent slate and a half. Tail rivets should pass between two adjacent slates and through a hole in the tail of the slate they are holding. The protruding shank of the rivet is bent down the slope.
And there you have it…five simple steps to make sure your fibre cement slates are fixed exactly as they should be. Thanks Cembrit!