GILFORD, N.H. (AP) – The deck on a vacation house collapsed Sunday night with about 40 people on it – an accident the town building inspector blamed on the builder’s failure to bolt the deck to the house.

Eleven people were injured, most with cuts, bruises and ankle injuries, according to Jim Hayes, deputy fire chief. All were treated and released.

The deck fell during a birthday party for a woman who turned 80, and she was among those treated at a hospital. Hayes said all were treated and released.

“It was just so quick. It came out underneath you,” said John Kwiecinski, son-in-law of Muriel Arbidson, who was celebrating her birthday. “People were sliding onto each other.”

Hayes said nearly 40 people were on the deck when it collapsed without warning at about 8:45 p.m. and dropped people to the ground. No one was jumping or moving excessively at the time, he said.

David Andrade, Gilford building inspector, said the deck was nailed instead of bolted to the house, a violation of building codes. “When wood ages, you lose adhesion to the nail,” he said.

The deck was built by property owner William Conaton, who rented out the building. Conaton will be required to rebuild the deck to code but will not be fined unless he fails to do so, Andrade said.

Andrade inspected the deck Monday and said it was strong enough to hold the weight of the people on it. But the nails attaching it to the back of the house worked loose and ultimately tore out, he said.

The deck was built two years ago.

, was supported by steel columns instead of wood posts, which was fortunate, he said. As the deck pulled away from the house, it slid down at an angle rather than breaking, he said. “It didn’t come crashing down,” he explained. This likely resulted in fewer serious injuries, he said.

The deck was about seven feet off the ground, he said. It was roughly 10 feet wide and about 80 feet long and attached to the back of the main house of a rental complex of cottages on Lake Winnipesaukee.

The cottage was rented by Arbidson’s extended family, which had been coming to Lake Winnipesaukee on vacation for more than 25 years, Kwiecinski said.

Relatives and friends of Arbidson had come from New York, New Jersey, Connecticut, Massachusetts and Virginia for the celebration. Arbidson is from Long Island, N.Y.

AP-ES-08-11-03 1657EDT