Get more from your slate investment.

Get more from your slate investment.

Improves ventilation

With SlateSpacer™, roofing slates do more than shed water: they become an important contributor to roof ventilation.

Improved ventilation reduces condensation and speeds drying of internal surfaces. This maximizes the service life of battens, boards, decking, rafters and other roof elements, as well as that of the slate.

Less than 1.2 mm (less than 1/16") thick, SlateSpacer™ enhances ventilation while preserving the water-shedding function of the roof system. Like louvers in a shutter or gable vent, each course of slate is spaced from its neighbor. Unlike louvers, slates are double-lapped, close-fitting and well supported.

On all types of roof

Condensation occurs wherever warm air meets cold surfaces. (Review condensation on slate.) It happens in all types of roof construction, closed or open, with or without an underlay.

It happens in the small, damp cavities beneath slates on closed roofs, which are common in Scotland and the US. It happens above the underlay in the batten space that is standard in much of the UK.* And it happens in the attic itself, in the case of open roofs installed without underlays, as is customary in many parts of France.

A louvered vent

Another louvered vent:
When slates are held apart, air passes (blue), allowing each course to function as a louver.

Better than "collar-and-cuffs"

To ventilate the attic or rafter space, many roofs rely on a "collar-and-cuffs" (ridge and eaves) approach. Collar-and-cuffs ventilation is useful. But on roofs with no underlay (France), or with an underlay that allows air to pass (sometimes at the seams, and gradually through the underlay's pores), the more thorough approach adds ventilation through the "fabric" (the broad surfaces) of the roof.

Small spaces add up. Twenty courses of standard-thickness spaced slate can double the aperture that dedicated eave or ridge vents typically provide. The entire surface breathes because each slate becomes a vent.

Roofing slate can be more than a cover. With SlateSpacer™, slate becomes a ventilation solution.

*Vapour Permeable Underlays concentrate vapour in the batten cavity

Ventilation of the batten cavity to keep the timber battens dry has always been important, but now with Vapour Permeable Underlays it is even more important.

As vapour passes through the underlay, it concentrates in the batten cavity. Some of this vapour will condense on the underside of the slates, and some will be absorbed by the timber battens. The more air tight the roof covering, the longer the batten cavity will remain wet. The more natural ventilation that exists between the slates, the quicker the batten cavity will dry, and the longer the battens (and slates) will last.

The flow of vapour up through the building fabric, insulation and underlay, should not stop (or nearly stop) in the batten cavity. Spacing slates encourages the flow to continue out of the building.