BCAB #956 - Aluminum T-Nails, Articles 9.27.2.2. & Article 9.27.2.3.

November 25, 1987

BCAB #956

Re: Aluminum T-Nails, Articles 9.27.2.2. & Article 9.27.2.3.

With reference to your letter of September 28, 1987, regarding the use of aluminum T-nails for cedar shakes and shingles.

Appeal No. 468 accepted the use of aluminum nails to CSA B111-74,which deals with nails generally, and includes reference to aluminum alloy as a material. The standard does not include dimensions for T-nails but we accepted the principle of their use.

Subsequently an opinion was requested from the Building Standards Branch on the acceptance of a specific type of nail. Their opinion, based on a draft CSA standard, 0.118.1M was that these nails contravened the draft standard, which was the only guide available. This opinion did not really relate to Appeal No. 468.

Article 9.27.2.2. requires nails for wood shakes and shingles to have a head diameter of not less than 4.8 mm. Article 9.27.2.3. permits staples for wood shingles, if the staple crown is not less than 9.5 mm. The latest draft of CSA 0118.1 "Western Red Cedar Shingles and Shakes" has increased its recommended crown size for T-nails from 9.5 mm to 11.0 mm.

The tests listed with your submission do not support acceptance of a 6.95 mm crown T-nail as being fully equivalent in performance to the nails required in the Code, although it may well be that they are adequate for the purpose. Further, the 6.95 mm is far smaller than the 11.0 mm which will be recommended in the new standard.

Under the circumstances we are unable to accept the 6.95 mm crown T-nail under the B.C. Building Code, for fixing wood shakes and shingles.

J.C. Currie, Chair