YOU’VE got that new table saw. And a hammer. A bag of nails. Some wood. All you need to build that extension onto the house, right?

Not so fast. Will your project be safe and meet local building codes? For virtually all construction projects, excluding things like small sheds and low stone walls, you’re also going to need a building permit. It’s municipal bureaucracy at its best, but the permits also ensure that your construction meets building and safety standards.

"Getting a building permit approved is either a treasure hunt or an obstacle course," said Donna Matichuk, a freelance permit seeker.

We asked several people for advice about how best to obtain building permits. All of them said the key is careful preparation, plus patience. It can’t be rushed.

Honolulu’s Department of Planning and Permitting has an online presence that not only provides information, but also gets the builder started, whether it’s an owner/builder job or a contractor doing the work. The interactive "Permit Pal" guide helps with determining which permits are needed, if any.

"Builders always take different routes, but it always starts out with permits," said Mike Horack of Custom Homes Real Estate Development.

Next, "the most important thing is doing an online application first," said John Meyers of Innovative Housing Solutions. "It generates a number you need at the one-stop permitting office at the Fasi Municipal Building downtown."

You can make an online appointment to have your plans reviewed at the same time "so you don’t have to sit and wait," said Wayne Inouye, chief building inspector for the city. (The building has security checkpoints, so bring identification.)

The plans are all-important, and buildings need engineering stress-analysis documents as well as blueprints.

"Know what you’re up against and ask questions beforehand," said Matichuk.

Her husband is an architect, and she started running plans for him to the permit office, becoming so familiar with the process that she runs permits as a part-time occupation.

"The biggest problem is when people don’t have adequate plans — that will slow you down a lot," said Matichuk. "It’s best to have a professional draw up your plans for most things because they know what is required."

The thing that slows down permit approval most is "incomplete plans," said Inouye. "I recommend using the online checklists. They give you a good heads-up what is needed in the drawings and a guide what to bring in."

"Easements can be a big problem," said Matichuk. "It’s best to get the architect’s or engineer’s eyes on the actual site so they can spot easement issues. Some people start construction, then get a building permit, and it might not be legal if there’s an easement problem. Do your research and don’t start without a permit."

"You can get a builder’s permit as ‘owner/builder’ to build almost anything, but not if you’re building a home for resale," said Meyers. "You have to own and occupy it for at least a year. But even owner/builders also need licensed electricians and plumbers as contractors. These parts of the construction are inspected separately."

Building permits can also be expensive.

"The building permit fee is based on a formula using square footage and projected value. An average two-story home will have a building permit costing about $4,000 or more," said Meyers.

In Meyers’ experience, "generally, it takes about seven to 10 days to get a permit approved." But your experience might vary.

"The fastest I had a plan approved was one day. The slowest was a year and a half," said Matichuk.

"It’s not instantaneous," said Horack. "It helps to have contact with someone who’s familiar with the process so they can prepare you, someone who knows their way around the building department. Even with everything prepared properly it can take several days."

The actual screening of plans is done behind the scenes, not at the permit counter. That’s why it takes a while. "Every once in a while they might overlook something at the counter. They don’t check everything; they’re just looking for certain things," said Matichuk.

Any tips based on their experiences?

"Yes! Watch out for Furlough Fridays, because the Thursday before and the Monday after are crazy," said Matichuk. Also, "the receptionists are very helpful," said Meyers.

"Seriously, be nice to the clerks. It’s a hard job, time-consuming and nitpicky, and it doesn’t help if you’re impatient and tick people off. It’s like a little community in there," said Matichuk.

"It’s true. The receptionists have a wealth of knowledge, and you can always email the department with questions," said Inouye.