Although we try to avoid the surprise of it with due diligence, one of the biggest changes in scope during a roof replacement job is discovering that the roof deck does not have OSB (Oriented Strand Board). Instead, it features 1x Decking boards original to the house framing.

Nowadays (think 1980ish – present), it’s the industry standard for homes to be built with OSB as the roof deck – at least 7/16” width. This gives the roofing materials a smoother, more solid surface to attach to, which means an overall more secure roof.

How does 1x decking affect the roofing process? Original 1x decking boards can have gaps, or knotholes that have fallen out over time. Most importantly, the exposed part of the shingle plus the nail flange (nailing strip) is not quite 6”, and a 1×6 (the most common 1x deck board on roofs) measures 5 ½”, meaning that there’s a high chance that your roofing nails are going to hit the gaps in between the boards and be more prone to blow off and leaks. So, by installing on 1x decking, roofing nails, and, more importantly, water can find its way into the gaps and holes, creating the potential for leaks down the road.

1x decking   1x decking

So – what are your options if you find yourself in a home that doesn’t have OSB on the roof deck:

  1. Our recommendation would be to sheet the roof deck during installation. Yes, it’s an added cost, but it’s the only way to maintain product and labor warranty and give you the best possible roof. If the roof replacement is part of an insurance claim and you have a code upgrade on your insurance, there is a potential that insurance would cover the sheeting if photos are submitted showing the gaps and holes in the existing roof deck.
  2. You can choose not to sheet the roof deck. Maybe your 1x boards are butted up perfectly close together and you haven’t had any leaking issues during the time you’ve lived in the home. We understand that it’s a big cost, and as long as we’ve done our job informing you that we can’t guarantee product and labor warranty by not installing the sheeting, we will proceed with the route of not sheeting if that’s what you’d like to do.

Finding out that your roof deck doesn’t have OSB on it isn’t fun, but JB Roofing & Gutters is here to talk you through the process of ensuring you’ve got the best roof solution for your home!

Joe Burkhart
About the Author

Joe Burkhart, the driving force behind JB Roofing, has been a trusted roofing expert in Ankeny, IA, since 2006. Joe’s passion for quality craftsmanship and personalized service comes from over 20 years of hands-on experience, starting his journey in the roofing industry back in the early 1990s. JB Roofing is more than just a business to Joe—it’s a reflection of his commitment to providing reliable, long-lasting roofs that protect homes and families across Iowa.