Get more from your slate investment.


Get more from your slate investment.

Reduces breakage

A slim, controlled separation between slates does not create breakage problems. In fact, it reduces a leading cause of breakage.

Walk testing

Walk testing* shows that SlateSpacer™ does not introduce breakage, even under challenging conditions:

  • Workman's weight: 91Kg (200 pounds)
  • Weight placement: concentrated on one foot on the slate's exposed end (including the corners)
  • Slate thickness 4 mm (less than 3/16")

Furthermore, SlateSpacer™ reduces breakage from improper nailing.

Proud nail heads on a starter slate.

SlateSpacer™ gaps are thinner than existing gaps.

Inherent, natural variances in slate thickness create widespread, intermittent gapping in virtually all slate roofs. Even sorting does not eliminate gapping. When a thin slate is beside a thicker slate, half the overlying slate projects, unsupported, over the thinner slate. Thickness variances commonly present 2 mm (slightly less than 1/8") gaps; in some markets, these gaps are considerably larger. The gaps that SlateSpacer™ present are approximately half those that occur naturally (1.2 mm (less than 1/16")).

SlateSpacer™ supports slates where they most need it.

SlateSpacer™ sits under the slate's exposed end, the part that receives the most direct loading.

SlateSpacer™ reduces breakage from proud nail heads (fig. 1).

Proud nail heads are one of the leading causes of slate failure. They can result from inattention or from a wish to avoid over-driving nails. Sometimes countersinks are insufficient to permit nails from being driven flush with the slate's surface (fig. 2). By separating slates, SlateSpacer™ has the effect of providing generous countersinks, increasing the margin for error (fig 3).

Spacers provide 30X more effective support than nail heads. Nail heads can break slates; SlateSpacer™ does not.

nail head breaking through slate proud nail head when the countersink is shallow SlateSpacer provides generous countersinks and does not break slates

fig. 1

fig. 3

fig. 3




*The usual precautions apply
In many markets, installers are cautioned to avoid walking directly on slates. They are taught to spread foot loads by walking on planks or ladders laid across the slates. SlateSpacer™ does not change this advice. With or without spacers, walking on slate involves risk. Slates can be slippery. Unbeknownst to the roof walker, slates may be cracked and ready to give way. Decks (support surfaces) may be uneven, and nails may be significantly over or under-driven, predisposing slates to break.


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