Is a one quarter inch nail penetration through roof deck a roofing defect? I would think it’s just a less than professional job only. Just curious.
Erol…with 7/16" osb being used as sheating I’m suprised when i don’t see a few coming through…jim
They’re coming through but they’re short. I’m wondering if there’s a minimum exposure requirement. It’s a $1 million dollar home.
No my way of thinking, in this area and climate, OSB roof decking is the defect. They cut it and do not waterproof the edges.
Just my never to be humble opinion :mrgreen:
I’ve always been under the impression that OSB is fine as decking material if kept dry by a careful roofing job. Is this incorrect?
Standard for most material around here is through all materials and a minimum 3/4" penetration into deck or through materials and deck if less than 3/4" deck material is used.
This is different in wind storm or seismic regions as I recall
They cut it and do not waterproof the edges (as the APA requires). Water gets into the edges and that is all she wrote.
One good thing about OSB roof decking. It blackens real easy when there is a roof failure and gives the client (if they check the attic, annually) a good indication of roof failure.
Again, just my opinion.
Roofing Nails
Your roofing nails should be long enough to penetrate your roof deck 3/4" or they should go all the way through your deck if it’s less than 3/4". For instance, if you have 1/2" plywood for a roof deck, your roofing nails should go all the way through and poke out in the attic. Please be advised that it can be difficult to find roofing nails longer than 1-3/4" in length.
Up here, typically use 5/8" roof deck with H-clips or T&G. Nothing less.
Nail length for new roof, would be 1&1/4".
Marcel:) 
Yes, 1 1/4" is what we used on a new roof. They penetrate the correct amount and were easy to shuck from a handful to between the index and middle finger for the first blow.
Here is the page from asphaltroofing.org otherwise known as ARMA
http://www.asphaltroofing.org/pdf/tb_221.pdf
Ed
Thanks Ed. Got the information I needed to make sure 1/4 ‘’ visible nail penertration viewed from attic was acceptable. 
**9.26.2.2. Nails
(1) **Nails used for roofing shall be corrosion-resistant roofing or shingle nails conforming to CSA B111, “Wire Nails,
Spikes and Staples”.
**(2) **Nails shall have sufficient length to penetrate through or 12 mm into roof sheathing.
**(3) **Nails used with asphalt roofing shall have a head diameter of not less than 9.5 mm and a shank thickness of not less
than 2.95 mm.
**(4) **Nails used with wood shingles or shakes shall have a head diameter of not less than 4.8 mm and a shank thickness of
not less than 2.0 mm and shall be stainless steel, aluminum or hot-dipped galvanized.