North Yorkshire Fire crews were called to reports of a roof fire at a house on St Winifreds Road, Harrogate at around 8.15pm on November 4.
Engines from Harrogate, Knaresborough and Boroughbridge were mobilised to the scene, but before they arrived the occupier had already extinguished the blaze with a garden hose.
North Yorkshire Fire and Rescue said a 'stray firework' had started the blaze, by landing on an extension to the house which was under construction.
In its incident summary for the evening, NYFRS said: "This was a house extension under construction ignited by firework. This was out on arrival as occupier extinguished using a garden hose prior to fire service arrival."