Yellowknife (Nov 17/04) - They'll keep hammering all winter long.

Allan Shortt, site superintendent for the new federal building under construction in downtown Yellowknife, said once the temperature goes below -35C, workers go outside to work for 20 minutes, followed by 10 minutes indoors to warm up.

If the temperature gets down around -50C, that's when the work will stop.

"That's kind of where skin starts to freeze," said Shortt.

The building is slated to be finished in June 2005 but Shortt said he expects it to be completely enclosed by mid-January. The last concrete roof slab will be laid this week. The area under the slab has to be closed in with tarps and heated, so the concrete will set properly. Two staircases will also be poured this winter.

Shortt said the project is on schedule.

"We're starting to insulate the walls," he said. "We'll start putting in the windows and doors this week."

The building will be green, with light produced by photovolterics -- a solar panel wall in the atrium.

Windows will open, so air conditioning won't be necessary. Toilets will use water from snowmelt to decrease the amount of chlorine going back into the water cycle.

That environmental consciousness actually began in the construction phase.

"All the formwork was shipped back to Edmonton to be used on another PCL project there," said Shortt.

Steel, electrical wire and metal pipes are saved and shipped south for recycling.

Wood is re-used closer to home.

"All our scrap wood goes to the dump to the recycling area for people to use as firewood," said Shortt.

Recycled materials are also being used in the project. For example, the concrete contains 20 per cent fly ash, a by-product of burning coal.