Oversized Bolt Holes a Problem?

In Mark Clement’s article (“Time-Saving Guardrails”) in the July issue, my eyes locked on to the size of the hole compared with the bolt. He oversizes the bolt holes by 1/4 inch (3/4-inch hole for 1/2-inch bolts). I used to oversize holes for bolts by 1/8 inch to 1/4 inch until the deck-ledger testing conducted at Virginia Tech was published in the March 2004 issue of your sister publication, JLC (jlconline.com). In the study, they oversized holes for 1/2-inch through-bolts by 1/16 inch to 9/16 inch and noted the importance of not oversizing holes.

(Editor’s note: According to the JLC article, the National Design Specification for Wood Construction requires bolt holes in wood to be a minimum of 1/32 inch to a maximum of 1/16 inch larger than the bolt diameter.)

I checked with some local engineers as well as a couple of wood gurus at building conferences I attended. Many told me that oversizing holes reduces the holding strength of connections, both in shear and tension. The maximum oversize mentioned by most engineers I queried is 1/16 inch. Several wanted precisely sized holes in wood and allowed only slight oversizing in steel.

Mike Guertin

East Greenwich, R.I. Mark Clement replies: When I build decks in which the post is surface-mounted to the band joist, I drill holes the way Mike suggests. My experience with the system I wrote about in PDB, however, has been that drilling holes the same size as the bolt (or within 1/16 inch) makes plumbing the post nearly impossible. By combining blocking, shims, and construction adhesive, I get posts dead plumb while maintaining rock-solid mechanical connections and maintaining production.

Contractor Reward Program

I was disappointed that you didn’t mention Azek Deck, a widely recognized brand in the industry, in Jefferson Kolle’s article on contractor reward programs in the July issue. We have a successful Contractor Referral program, with 3 million Web site hits per month. Of those, 30 percent click on our “Where to Buy” link.

In order to participate in the Azek Deck Contractor Referral Program, a contractor must

• install an Azek deck,

• fill out the contact information form, which is available at this link: azek.com/BuildAZEKDeck (case sensitive),

• sign a hold harmless form.

Plus, an Azek territory sales manager must visit at least one Azek deck built by the contractor. When contractors are signed up, they will receive

• a welcome letter with local rep support information,

• an Azek Deck Contractor Box containing marketing materials, brochures, color samples, and actual deck samples,

• an additional box of Azek Deck samples,

• Azek Deck leads,

• 50 deck brochures.

Maureen Murray

Azek Building Products