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April 7, 2020 in Code and Construction, Roof, Siding & Windows

Shingles: Drainage Gap Required

If you’re thinking of a new build or a renovation where shingles are in the mix for the siding, here’s a bit of information you need to know.

In this part of the world, National Building Code mandates a 1cm gap between the shingles and the housewrap of the exterior wall.

In all areas of Charlotte and southern York County, a shingle backer of some nature, such as this purpose-built material, is required.

The intent of this gap (called a capillary break) is that there is sufficient room for water to travel down the housewrap, or vent via evaporation should water get behind the shingles. Failure to install shingles this way may result in moisture build-up between the shingles and the wall, resulting in early decay of the shingles or water penetration into the exterior wall.

There are several ways to achieve this capillary break. One way is to use a manufactured “shingle backer.” One variety looks like a really big pot scrubber – see the included image.

Another way is to line the wall with garden lattice before applying the shingles.

Questions? Give us a call at 466-7369.



Southwest New Brunswick Service Commission

SNBSC is an independent organization, enacted by provincial legislation that provides regional services to municipalities and the rural district. The organization is governed by a Board of Directors comprised of the mayors of all the municipalities within the region and a representative of the rural district.

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