Alumaz Roofs

A slate roof will never have to be painted and is virtually maintenance free, though in the rare case where repairs are needed, tiles are easily cut to the required shape, unlike roof tiles which are not easily matched.  Slate is the most versatile roofing material, since it can be easily guillotined on site by hand and can therefore be used on all roof shapes and designs, making way for spectacular roof features, like dormer and eyebrow windows, as well as several different roofing systems, from the Conventional double overlap in which the minimum pitch is 30 degrees, to the single overlap system (Alu-maz) with a pitch of as little as 12 degrees.  Two choices of hips and ridges are also available - Mitred or Boston style (saddled) to the slate roof owner, which can provide that additional, individual finish to the elegant slate roof.

Alumaz Slate Roof Installation

  • Minimum Pitch - 17°
  • Weight per Roofing m2 - 43kgs
  • Available Colours - Multicolour, West Country, Silver/ Blue
  • Slates centre nailed
  • Length of nails to be at least twice the slate thickness
  1. The roofing slates are available in various sizes but all vary in thickness from 9-15mm. These slates when delivered to site require to be sorted and are generally graded in six categories, according to thickness.
  2. All timber-work and gutters must be completed before slating can commence.
  3. The timber battens must be "marked out" to indicate the position of all the vertical joints.
  4. The Slates are then loaded onto the roof. Ladders & Labourers may be used for moving the slates onto the roof up to  a maximum height of two storeys, there-after a mechanical hoist, usually supplied by the builder, will be required.
  5. The roof is laid in such a manner that the thicker grades are utilised from the bottom up, i.e. thicker slates at the eaves, thinner slates at the ridges.
  6. When commencing slating, a bituminous roofing felt strip is laid horizontally on the first batten above the facia board at the gutter.
  7. An aluminium foil strip 225mm wide is then laid horizontally to the first batten covering the lower section of the roofing felt. The aluminium serves to cover the roofing where exposed by the vertical joints.
  8. The slates are now laid horizontally on top the roofing fall in straight lines. This process is then repeated, with a layer of roofing felt plus a layer of slate nailed to each batten.
  9. If the battens are well laid, horizontally, the batten edge of the roofing felt will form a straight line which can be used as a guide to keep the slates straight. Care must be taken to ensure that the slates are laid in straight lines, horizontally, with the joints vertical from the eaves to the ridge. The slates abut against each other to form the vertical joints.
  10. Slates are normally 280mm long with varying widths (top nailed) and the roofing felt is normally 450mm wide and 30m long. This means that the roofing felt is always nailed one batten (190mm) higher than the slate on every row of slates laid. Consequently, the roofing felt forms a double layer under every course of slate.
  11. Hip Slates (i.e. , slates which are similar to those used throughout the roof but not necessarily the same width, and not drilled) should be used when hips, valleys, ridges, etc. are to be slates.
  12. When calculating slate requirements for an roof, the conversion from roofing square metres to flat square metres is approximately 1,5.