NEWMARKET, Ont. -- A joint funeral service will be held this afternoon at a church in Newmarket, Ont., for four family members killed in a house fire last Friday.

The fire in the town of East Gwillimbury, north of Toronto, claimed the lives of 55-year-old lawyer Kevin Dunsmuir, his 51-year-old wife Jennifer and two of their sons -- 16-year-old Cameron and 19-year-old Robert.

A third son, David, was away at university and in his obituary tribute to his family, he wrote that his parents and brothers were larger and more impactful than could ever be described.

Fire officials say there was no smoke detector on the on the main floor and the one serving the upstairs was wired through the main floor laundry room where the blaze broke out.

Firefighters arrived to a home fully engulfed in flames and the four victims in a second-floor bedroom.

Their escape route was blocked.