Up and down the streets of every neighborhood in Seattle, new construction is a familiar sight. But in one driveway in Ballard, the details and angles on a structure being built defy the typically boxy nature of the city’s new wave of homes and apartment buildings.

For fans of the Harry Potter book and film series, the project should be instantly recognizable.

Jon Chambers, a Seattle tech veteran with time on his hands after stepping away from his most recent job, has built a sizable recreation of Diagon Alley, the London shopping area for wizards that is accessible through a secret brick wall located behind a pub.

“I’ve always wanted to do something massive for Halloween or Christmas,” Chambers said during a break in construction this week. “I was born the day before Halloween, and October is like my power month. So I decided to quit my job and focus on this crazy thing.”

Chambers, who turns 46 on Monday, had previously worked as creative director at the Seattle mobile app company Ubermind, which was acquired by Deloitte in 2012. He was most recently director of design and a developer at OpenCar, the Seattle startup that was acquired by INRIX, the Kirkland, Wash.-based traffic analytics company.

“My 18 months was up. We were leaving things in a good place for INRIX to take over and continue the work that we were doing,” Chambers said. “Really what I love to do is build products in that startup environment. So this is kind of a creative refresh project for me before I start my new thing.”

Chambers and his wife Jennifer, the director of Fund Administration and Operations at Madrona Venture Group, have lived in their house across from Ballard’s Whittier Heights Elementary School for 20 years. The single-story brick structure, which Chambers remodeled himself over the years, looks like other houses on the block — with the exception of what’s going on in the driveway these days. The couple has two daughters — Avery, 7, and Haley, 11,

“Obviously I loved the movies when they came out, and when they came out the girls weren’t born yet, I don’t think,” Chambers said. “It seems like there’s a resurgence of Harry Potter. For two years now the girls have been obsessing over Harry Potter. Everybody’s having Harry Potter birthdays and there’s Diagon Alley in London and Universal Studios [The Wizarding World].”

So about four to six months ago, Chambers started thinking about creating the Alley.

He’s got a background in illustration and in his 20s he did construction framing for his uncle. He’s done random general contracting and trade jobs, including painting in high school for three summers.

He loves to sketch and draw and his tech work as a designer has tapped into those passions. But in the garage behind the house he has assembled an impressive wood shop. It’s here that he goes to have fun.

“Design is a very logical process that you go through to solve the design problem, whereas I go to my shop, I think of something crazy to do and throw it together,” Chambers said. “Usually it’s something fun for the kids.”

While the Harry Potter Wiki lists about 30 various storefronts that make up the cobblestone Diagon Alley, Chambers has managed to squeeze six into his driveway: Eeylops Owl Emporium, Ollivanders wand shop, Quality Quidditch Supplies, Magical Menagerie, Flourish and Blotts bookshop and Madam Malkin’s Robes for All Occasions.

I was born the day before Halloween, and October is like my power month. So I decided to quit my job and focus on this crazy thing.

If there’s time before Halloween on Tuesday, he may add a seventh, with Gringotts Wizarding Bank at the end of the driveway in front of the garage, calling the potentially 20-foot-tall structure the “coup de’grace.”

It’s a furious construction pace that only got under way two weekends ago, when an army of volunteers showed up to make the big panels that serve as the main support for the detailed facades. As he’s posted pictures on social media, more people have stopped by to donate random pieces of wood or buckets of paint.

“It’s taken on a life of its own!” Jennifer Chambers said of the thing that’s parked where her car used to be. “I’ve been blown away at how many people have stopped by to help and donate. I had no idea it would be this big.”

The Chambers’ neighbor, Bill Dunnell, works from home as a financial planner, so when the markets close, he wanders next door with his tool belt on. He’s been doing all the roof work on the project and has donated shingles and other stuff lying around his backyard. At one point during GeekWire’s visit, Dunnell left and came back with an old cedar gutter.

“I think it’s crazy. I love it,” Dunnell said. “He posted the notice on Facebook. I felt like saying, ‘This is a waste of money and time and effort … when do we get started?!’

Additional touches will help the Alley truly come to life for Halloween visitors.

He posted the notice on Facebook. I felt like saying, ‘This is a waste of money and time and effort … when do we get started?!’

Chambers is doing digital paintings for each shop window showing a different perspective within. He’s taking the individual squares, laminating them, putting them on and putting muntins over the top. He’s also making props on his own 3D printer, such as corbels and lanterns which will hold candles.

Friends who have worked in Hollywood and produced shows will also be coming by to help dress the set and deal with lighting. And then there are the actors.

“We’ll have actors here on Halloween, that are going to keep things alive a little bit,” Chambers said. He plans on being Hagrid, the half-giant Keeper of Keys and Grounds at Hogwarts. One of his daughters is going to be Ginny Weasley and the other is going to be a random witch. One friend is going to be Snape, and another friend is “just a dead ringer for Harry Potter.”

The Chambers are also hoping that visitors who are inclined to stop by and see the temporary Diagon Alley (the plan is to leave it up through Christmas) are attracted to a more long-lasting cause. Matt Bencke, the co-founder of Mighty AI, died on Oct. 18. He was the first CEO at Madrona Venture Labs, the startup incubator, and met the family over time through those Madrona connections.

“The girls were really touched by his story, and they were really curious about this disease, pancreatic cancer that he had, and why can’t it be cured,” Chambers said about his daughters. “That was their choice for the cause, to donate any proceeds that we get.” (Visit this page to donate.)

That notion of giving plays in well with Chambers’ belief that “that’s been the really cool part of this” — bringing the community together.

As for when and where Chambers will head back to a regular day job, he said he’ll be on the lookout for another startup opportunity that fits his skill set and that he’s excited about.

He said he’s going to keep doing his creative thing until then. And the wheels are definitely turning as he looks past Diagon Alley and toward his house.

“I’ve thought it would be cool to do a Millennium Falcon. On the roof.”