It started 22 years ago in a small room above a solicitor's office. And September marks the end of one era and the start of another for the Bradford-based building society with green credentials.

The Ecology Building Society is moving to its ultra environmentally friendly new headquarters in Silsden at the end of the month. With its own solar electricity plant, water recycling system, grass roof and reclaimed building materials the building captures the society's ethos of green building.

The 16-strong staff are getting ready to move to the £750,000 building at Belton Road. But one employee who will not be joining them is Pat Pettit.

A stalwart of the society, she is retiring after being with the group since 1982. But Pat has given the new building her seal of approval.

"I was a bit unsure about it at first but we had a site visit a couple of weeks ago and I must admit I liked it," she said.

"It is different but it does portray the Ecology Building Society with all the different types of wood, the grass roof and the reclaimed stone."

Pat is well placed to judge the new HQ. In 1985 she helped transform a former flower shop in Cross Hills into new offices for the society.

"We transported all that belonged to the society to the flower shop," she said.

"We scrubbed it all out and decorated it. We weren't averse to doing a bit of hard graft!"

Paul Ellis, chief executive, paid tribute to Pat's commitment. "Because she has been with us from the beginning she has seen the way we have grown and has taken a lot of personal pride in that," he said. "She has always been someone who you can rely on." Mr Ellis said he was pleased that Pat liked the building, but said it may not be possible to fulfil her request to name it Pettit House. "It's the first time we've had a purpose built building and it marks the progress the society has made," he said.

"We've had very strong growth rates year on year and that's reflected that we can move on to this next stage and have a solid base for the next 20 years."

Pat is now looking forward to retirement and hopes to take up keep fit classes as well as part-time work in a charity shop. While she is pleased to leave the world of work behind, she said she will always have happy memories of her time at the society.

"It's such a proud thing to have been part of," she said. "We hoped it would grow and fortunately with good management it has. It has really been worthwhile and I am proud I have seen it through to this particular stage. Paul Ellis and Pat Pettit are pictured at the firm's new site.