The business was running out of space to store parts, now had a branch dealing in motor glass, and wanted space for staff to work out of the weather.
The large shed was just the start of an upgrade that would move right through the large section during the next few years, she said.
Autoparts 2000 sends parts all over New Zealand, often communicating with customers by a membership-based internet system. Mrs McDonald said her husband's experience with current cars was the core strength of the business.
"Chris has that knowledge embedded in him.
"He has been working in the field for 25-30 years."
She said the vehicles staff mostly dealt with were Japanese and aged from the 1990s on, the type most common on New Zealand roads.
The ones they stripped for parts were unwanted or had been in accidents.
The vehicles were given or bought for up to $1000.
Then they were dismantled, the useful pieces stored and the rest taken away and sold for scrap.
The high price of used steel was making that easy, Mrs McDonald said, and it was keeping their yard much tidier.
"Once upon a time you would have to pay someone to come and take scrap away. Now they pay you."
Their parts customers include mechanics, insurers and other parts companies.
Some cars had faults the staff came to know well, she said - for example, a line of Falcons with faulty door handles. Others were so well made that they were difficult to take apart.
The McDonalds employ four full-time staff. Mr McDonald does most of the selling, with his wife part-time on accounts. Staff in the yard dismantle cars and do a small amount of repair work.
The yard runs back behind the Somme Parade shop front almost to London St, with ordered collections of cars, windscreens, bumpers, wipers and all the rest.
Mr McDonald's history with car parts began when he was 18 and started working for Kevin Stevens in the Aramoho auto wrecking business of the time.
After more than a decade, he and his wife started Autoparts 2000 in the former Burgess Matting building in Duncan St, Wanganui East. When they were offered the opportunity to buy the Aramoho business, they took it.
The McDonalds eventually bought a house next door in Somme Parade, then a house on the other side for Mr McDonald's mother, Val Waters. When their business partners shifted overseas, the McDonalds bought them out.
The family now love being so close to the Whanganui River and to their business.
Mrs McDonald said she and her husband often "walk the bridges".
