Abstract: A method is provided which permanently embeds a fire retardant such as diammonium phsophate into wood shingles, wood framing members or other wood members by means of blasting a special slurry of the fire retardant into the body of the wood with an airless spray gun, or alternatively soaking or dipping the wood in a softening solution and then emersing it in the fire retardant slurry which is subsequently pressurized to over 100 pounds per square inch, in either case the diammonium phosphate granules being embedded into the wood where they are protected from being leached at by rainfall and the like by a nonsoluable, nonvolatile carrier liquid.