The Jarrettsville Volunteer Fire Company was alerted for a reported dwelling fire in the 1400 block of Knopp Road. Chief 7 arrived minutes after dispatch at the scene of a two-story single-family dwelling with heavy fire showing from the Alpha side on all levels. Engine 714 soon arrived and advanced a 2 1/2" hand line to knock down the bulk of the fire. A water supply was established at a nearby stream to provide water for the fire scene. Upon investigation, crews determined the first floor had suffered severe structural damage and withdrew from an interior attack until conditions improved. Once it was safe, crews were able to advance hand lines into the dwelling and extinguish the remaining flames. Crews remained on-scene for an extended period of time due to the amount of overhaul required. The Maryland State Fire Marshal is investigating the cause of the blaze.