This wood filler from Ronseal has been specially designed for re-building rotten wood and for major repairs deeper than 5mm on window frames sills doors and door frames around the internal & external areas of your home. It provides tough and durable repairs to any wood it's used on. It's best applied with a filling knife or spreader and can be drilled screwed or planed once dried. It's sandable heat resistant and drip resistant too.