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Inspiration2 min

How Fire-Rated OSB Outperforms FRT Plywood

Both fire-rated OSB and Fire Retardant Treated (FRT) plywood are commonly used in fire-rated wall sheathing and roof deck applications. Because these materials are always evolving, it’s good for architects and builders to know how they compare to each other.

An engineered wood product like LP® FlameBlock® Fire-Rated Sheathing combines a layer of ignition-resistant, cementitious coating with a layer of OSB. It carries an Exposure 1 classification, which means it can withstand normal exposure to moisture during construction. In contrast, some fire-retardant treatments are applied after the plywood is manufactured – and the treatment is sometimes water-soluble, requiring it to be protected from moisture during construction. 

A fire-rated OSB product like LP FlameBlock offers both flame-spread resistance and burn-through resistance in the same panel, as verified in tests like the 30-minute Class A Flame Spread Rating (ASTM E84, UL723) and 15-minute Thermal Barrier Protection test (UBC 26-2).  FRT plywood has a flame spread rating, but no rating for burn-through resistance. 

Fire-rated OSB sheathing has load/span and shear design values that are superior to FRT plywood at the same thickness. In addition, engineered wood sheathing reduces dead load and wall thickness versus FRT plywood. This gives architects more flexibility in designing wall openings, plus more options in framing and bracing to meet structural requirements.

When architects specify fire-rated OSB sheathing, it’s important for builders and subcontractors to “respect the spec” and stick with a material like LP FlameBlock that has so many advantages over FRT plywood.

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Industry Trends3 min

Answer Demand for Urban Living: Best Practices for Tall and Skinny Housing Builds

Many U.S. cities are experiencing population booms, and their new residents are demanding to live closer to the city’s core. This home building trend is encouraging “tall and skinny” construction, which is helping builders maximize the constraints of building on tight urban lots.

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News & Stories2 min
LP's COVID-19 Response

To Our Valued Customers, At LP, our first priority – now and always – is the safety and wellbeing of our employees, our customers, and the communities in which we serve.

News & Stories3 min
Watch: LP on Making It with Amy Poehler & Nick Offerman

It’s no secret there is an increasing trend of sheds being transformed into alternative uses such as backyard getaways, hobby hideouts and virtually any unique purpose one can dream up. That means it is more important than ever to have tips to creating these in-demand aspirational sheds in your back pocket.

Business Advice3 min
Remodeling Historic Homes: Best Practices for Earning More Leads

If you’re interested in historic home renovation and want to improve the flow of profitable leads, consider aligning and working more closely with your local historic landmark commission.