Fire-Retardant Treated Plywood

Fire-retardant treated plywood is used where the Ontario Building code requires this type of plywood as part of a rated assembly for fire separation in construction.  

Hanford Lumber stocks sheathing grade plywood treated with Dricon® fire retardant. Dricon® is the recognized leader in fire-retardant protection and has been specified by architects and engineers for decades. The Dricon® process utilizes hygroscopic salt compounds which are pressure treated into the plywood to provide fire resistance in buildings as part of ULC and Factory Mutual tested and rated assemblies. A continuous roller stamp on one face indicating that the material has been treated with Dricon® is assurance for both you and the building inspector that the material is fire-retardant treated.

As Dricon® fire retardant is a water-borne process, material treated with Dricon® can only be used in interior applications or where there is little to no possibility of the material getting wet.

Common questions about fire-retardant treated plywood:

  1. Fire-retardant plywood on its own does NOT have an hourly resistance rating. The approved, rated ULC or Factory Mutual assemblies, which may contain fire-retardant plywood as a component, would have the hourly resistance rating.
  2. We often get requests for plywood which is BOTH fire-retardant treated as well as being treated with regular pressure-treated preservative. This is NOT possible as fire-retardant preservative is for indoor use only and the treatment processes are dissimilar and NOT compatible with each other.

Hanford Lumber always encourages our customers to check with the local building officials for the correct use and application of these products.

Dricon®-treated sheathing available

ThicknessWidth x Length
1/2”4’x8′
5/8”4’x8′
3/4”4’x8′

Other plywood, including other sheathing thicknesses and good 1 side plywood can be obtained on a special-order basis. Please enquire with one of our sales associates. Minimum order quantities may apply.

For any further sizing and or grades not listed please reach out to our sales desk for a special order inquiry.