Here we explain in detail how to fit roof slates using the nail and rivet fixing method. If you are fitting a roof at a pitch lower than 15 degrees, use the hook fixing method, which is recommended for our Birkdale low pitch slates.
Before fitting roof slates, consideration should of course be given to the dimensions and headlap, as well as the specification of underlay and battens.
Nail and rivet fixing method for fibre cement roof slates
All slates should be fixed in accordance with BS 5534 and BS 8000-6
Slates should be laid broken bond using slate-and-a-half width slates in alternate courses, formed from double width slates at verges, hips, valleys and abutments.
Double or slate-and-a-half slates must be fixed with 3 No. jagged copper nails (30mm x 2.65mm) and 2 No. copper disc rivets (19mm x 2mm stem, 19mm dia. x 0.5mm thick base).
Any full slates are centre nailed with 2 No. nails and restrained at the bottom edge with a rivet.
A maximum 5mm gap should be left between adjacent slates to allow for disc rivet shanks. 3-4mm is optimum.
You should nail slates firmly but do not drive them too tight to the surface of the slate.
For full details of the headlap and rafter lengths suitable for hook fixing, please refer to page 5 of our slate fixing guide.
1. Setting out of battens
Care must be taken when setting out to avoid the need for rectangular-cut slates less than half the normal width, as these may be difficult to fix.
Roofs should be set out with battens to the appropriate gauge. Calculating the gauge using the formula on page 10 of our fibre cement slate fixing guide.
gauge = length of slate - lap required / 2
Allow for the eaves courses of slates to overhang the fascia or tilting fillet so that the tails align with the centre of the gutter (approx. 50mm).
A vertical or raking batten is advisable at the verge and at intersections.
Allow the eaves slates to overhang into the gutter by approximately 50mm. The verge overhang should be restricted to a maximum of 50mm.
2. Under-eaves battens and first under-eaves slate course
Set out both under-eaves battens to accommodate the two lengths of under-eaves slates allowing for correct lap and gauge. See Table 6, page 26 of our fibre cement fixing guide. Cut the under-eaves slates from a standard slate and drill 2 no. 4mm diameter holes approximately 10-15mm in from the top cut edge and head nail the first under-eaves course along the eaves.
3. Second under-eaves course
Cut and nail fix the second under-eaves course to the lower eaves batten with slate-and-a-half widths at the verge. Ensure a copper disc rivet is fitted centrally between adjacent slates (5mm gap) to align the pin with the hole in the front edge of the first course of full length slates.
4. First full course
At the verge, a second hole (4mm dia.) is required to allow for the copper disc rivet for the next course. This is drilled 50mm from the outside edge of the slate and 25mm plus gauge from the bottom edge, or tail.
Continue to lay the first course of full length slates, twice nailing each slate, and inserting a copper disc rivet between adjacent slates aligned with the hole in the front edge of the slate above.
When the next course of slates is laid above, the rivet shank is passed through the hole in the front edge of the slate and the rivet shank bent 90° so that it faces down the roof slope to secure the tail of the slate.
5. Correct riveting
Disc rivets are bent downwards to hold the tail of the slate to protect against wind uplift. To achieve the correct bend in the rivet shank, it is best to tap it twice with a hammer, once at about 45° to the pin, and then finally onto the surface of the slate.
At the verge, a second hole (4mm dia.) should be drilled 50mm distance from the outside edge of the slate, and 25mm plus the gauge distance from the tail, to allow the disc rivet pin to be inserted for the next course above.
6. Riveting at verges and abutments
At verges and abutments, lay the first full length slate-and-a-half slate, ensuring that 3 no. 4mm dia. holes are drilled on the batten line with 2 no. additional holes for the copper disc rivets.
For remaining courses, where single and slate-and-a-half slates are used, a third disc rivet hole is needed to allow for the rivet pin for the next single width verge slate (at point C:
This is drilled half the single slate width from the side of the slate and 25mm plus the gauge distance from the tail.
7. Slate the rest of the roof
Continue diagonally up the roof with standard size slates, trimming to verges, hips, valleys and ridges as required.
Slate-and-a-half widths should be used if the half slate is less than 150mm wide.
At valleys and hips where slates need to be cut on the rake, wide slates must be used to maintain an adequate width and sidelap at the head or tail.
8. Roof apex or top abutment
At the roof apex or top abutment, an additional top course batten is fitted directly above the last full length slate batten. The last full length roof slates / short courses are cut to length so that their top edges rest on the lower batten and are centre nailed as normal.
The top course slates should be cut to length and head nailed as per the under-eaves course slates with a disc rivet fitted to the tail.
Note: To ensure the top course slates lay neatly, a thicker batten can be used to compensate for the thickness of the slate course below.
Full instructions, along with installation guides to roofing accessories and trims, can be found by downloading our guide to fixing fibre cement slates.
Video instructions on how to achieve a low pitch fibre cement roof are also available.
If you have any questions or difficulties with the installation of Marley Eternit fibre cement slates, please contact the Technical Advisory Service