Derek Bridger – Princeton Zoning Officer

Mark Freda: Derek, thanks for joining us today.

Derek Bridger: My pleasure, Mark.

Mark Freda: Alright, first question, what is an ADU?

Derek Bridger: Right, an ADU. I’m gonna kind of go off the definition here. It’s a group of interrelated rooms that constitutes an entirely self-contained portion of a principal residence or a one family dwelling. Or it could be located in an accessory building on the lot as a principal dwelling. It contains housekeeping for one family. Doesn’t have any cooking or food prep facilities or sanitary facilities, or enclosed space in common with any other part of the building in which it’s located. So it’s gotta be separate in their own building on a lot, or they could be part of the main house. They could be in the basement, they could be in a wing of the house. But it’s gotta be separate as far as the kitchen and bath and housekeeping stuff. But you could have common air conditioners and heating equipment. Or if it’s in the same house, you could have the garage could be part of it too. But once it becomes separate, the garage becomes an issue because they can be sold separately. So it would contribute towards the size of the ADU, which we’ll get to that size a little bit later on here.

Mark Freda: When did Princeton put the ordinance allowing ADUs in place? How long has that been around?

Derek Bridger: It’s been in since June of 2020. Both communities had similar ordinances before, but I would say they were more restrictive. The township had what was called a flat ordinance where you could have a flat inside of a house, but it had to be contained in the principal dwelling, so it couldn’t be a detached dwelling. The borough had secondary residences, which required a little bit larger lot area, like 25% larger lot area than the prescribed lot area for his zone, and it only allowed two habitable rooms, which is basically a living room or a bedroom. Kitchen’s not a habitable room. Laundry rooms are not habitable, hallways, that type of stuff. So they kind of opened it up and they’ve been fairly popular. There’s been quite a few applications.

Mark Freda: What were the hope for outcomes by putting this ordinance in place?

Derek Bridger: I think there was a couple of objectives. One was to just provide people with more housing sources. I think to try to hit the missing middle, which is an elusive thing in a place like Princeton where your land values are so high. It also allows people to age in place so they could get the rental income from that apartment. They could sell the apartment. They could just get money to stay in town and pay their taxes and living expenses. It does create kind of a middle space of properties in town. The prices continue to go up here. I’ve seen them go as high as eight or nine hundred thousand dollars. But I think between five and eight and there’s just not a lot of other stuff in that range. Because anything that’s seven, eight, or nine hundred thousand dollars with a small house is gonna be torn down and redeveloped into a larger house probably. The maximum is the minimum as far as the size of houses goes.

Mark Freda: It’s kind of crazy what’s been happening. Do you have an idea of about how many ADUs have been constructed since this ordinance came into place?

Derek Bridger: It’s been around 40. Some have been in houses, some are outside. Some were five or six older ones that had been approved in the old code and they were kind of grandfathered. Some haven’t been built. Some people think it’s a great idea, but it still adds up. A kitchen is 50, 60, or 70 thousand dollars. Your bathrooms and you have to have certain finishes. You can’t cheap it out. Or you can, but you’re spending money on an asset like that, it just costs a lot of money to build anywhere. And especially with the environmental impacts of like storm water control and that type of stuff. It adds up. A lot goes into it.

Mark Freda: Okay, so here I wanna spend a little time on this question because, and I know in your answer to the first question you kind of hit on this, but I really wanna narrow in on it because people keep asking me this. Can an ADU be connected to an existing home, or does it need to be separated from the existing home?

Derek Bridger: It can be connected to the existing home. There’s some rules. You can’t have a door on an ADU that faces the same way that the door of the main house does. So typically the principal dwelling door will face the main street. So the ADU door would have to face a different direction. Because they didn’t want two doors facing the front.

Mark Freda: So the main entrance of the ADU has to, that doorway should be like on the side, so to speak?

Derek Bridger: Exactly. So they can be part of the house. They could be in a basement. I’ve seen people cordon off a portion of the house with a separate entrance to put them in there. And then they can be separate structures on a lot. I mean, the minimum setback is five feet for a one and a half story, 20 foot high ADU. The majority seem to be separate, detached units.

Mark Freda: Okay. So it can be either one, and it just depends. Obviously they work those details out when they come to visit you probably.

Derek Bridger: Yeah. And if they’re in the basement, then you gotta have egress windows and that type of stuff. So it’s a little bit of work involved, but that’s a cheaper alternative for somebody who wants to get some income is to put it in your house, but then there’s less privacy. You have somebody else living in different effects than that detached one.

Mark Freda: And that’s an important comment on the windows, right? Because most basements have tiny little windows and nobody’s getting out through those windows. And your history in the fire department, it’s an important thing. You gotta get people out of a basement in the event of a fire. All right, so here’s another one that I get asked a lot. How big can an ADU be or what decides how big an ADU can be?

Derek Bridger: Okay, so the basic size, the maximum size, is 800 square feet or 25% of the floor area ratio of the house. So if your house is 5,000 square feet, you could have a 1,250 square foot ADU. But it’s limited to three habitable rooms. The common design we see is there’ll be like a great room on the first floor with a kitchen and a dining room area and a living room area. We consider that living room area one habitable room, and then they could have two bedrooms in addition to that. That would be their three habitable rooms. But a kitchen’s not a habitable room, hallways are not, laundry rooms are not. Those are the parameters, but you can get some pretty big great rooms. I think we haven’t seen many over a thousand square feet. Most of them are 800, that seems to be the sweet spot. And it just has to fit into the zoning of the property too. So your floor area ratio, which is basically the measurement of the area of a house, that’s a percentage of the lot area. If your FAR is 25% and you’re in a 10,000 square foot lot, you have 2,500 square feet of building on your property. So the ADU still has to fit into that parameter. So if you have a house that’s already at 25%, then you’ve maxed out, you can’t get an ADU.

Mark Freda: So it’s not like every property with a house is eligible to add an ADU, right?

Derek Bridger: In that case you’d have to do it inside the house, but you can’t add another one. So that’s the issue there.

Mark Freda: People really should make sure they investigate enough beforehand. Sounds like an informal discussion with your office makes sense.

Derek Bridger: Yeah, and we’ve got a lot of professionals in town, architects who kind of specialize in this, and they’re very knowledgeable. We get a lot of inquiries. It’s been a pretty active program since it was opened up.

Mark Freda: And I guess the intent is for somebody that owns a property in town now and needs income to help cover taxes or whatever expenses to stay in town. That’s a great tool to use.

Derek Bridger: It is. My daughter lives in California, so I’m out there quite a bit in Los Angeles. And the ADUs are everywhere out there. They have similar situations, they have a worse housing crisis than we do because it’s even more expensive. But you get used to them. I think people were a little shocked. Anytime anything changes, they’re concerned. But I think they’re accepted out there and it’s a nice niche housing tool to address the town’s need for housing. We have a shortage. We’re getting a lot of affordable housing with market rate housing too, but it’s not cheap housing. The market rate housing is thousands of dollars a month. This kind of fills a gap in the affordability of the town.

Mark Freda: My personal perspective is that it works better when it’s someone that says, “I’m gonna stay in my house, or I’m gonna move into the ADU I build and rent out my house,” as opposed to someone who buys a property and says, “I’m now building a newer, bigger house and an ADU and I’m just doing this for the profit.”

Derek Bridger: Right. Anytime there’s somebody who owns the unit on site, there’s just a little more control, but they have been sold separately, so you can do that too. That’s just kind of a challenge from our end, just to make sure that we approve it so that when it does get sold, it’s still legal and hasn’t been expanded. Enforcing it is always a challenge.

Mark Freda: Let’s talk a little bit more about the zoning setbacks for the ADU. I know you kind of mentioned that, but I just wanna hone in on that a little bit more because I know I’ve had people come to me and say, “Jesus, this thing got built. It’s awful darn close to my property line.”

Derek Bridger: I get those calls too. They can be pretty close to a side or rear property line. They’re allowed in your side or rear yard. They’re not allowed in the front yard setback in the borough, but you could be in what looks like a front yard, but it’s not the front yard setback. As far as the side and rear yard where they’re permitted, you could be as close as five feet and 20 feet tall, but it’s limited to a story and a half. If you get larger than that, if you become two stories, then you have to go with the setbacks of the main house, which in the township is typically 15 foot side yard setback. In the borough, it ranges from a minimum of eight to like 10, or there’s combined side yards there. But it can be close and it can be shocking when somebody starts to build one. I always advise neighbors would make my job and probably the elected officials’ job a lot easier if they talk to their neighbors before they build a project. Even a new house. It just gets people like, change is hard when you live right next to it, so you’re gonna experience it for four to six months.

Mark Freda: So when somebody goes to add an ADU on their property, do they have to do the notice to everybody within the 200 feet of the edge of the property line or not because it’s allowable, it’s an as-of-right application?

Derek Bridger: Exactly. It could just pop up and as a neighbor you’d have no idea until they’re building something. You see the bulldozer in there and they start excavating. So it’d be nice to your neighbors and let them know ahead of time.

Mark Freda: Let me just change direction here a little bit. Derek, how long have you been the town’s zoning officer?

Derek Bridger: I started in former Princeton Borough in 2001 and I was the assistant zoning officer, assistant historic preservation officer, assistant affordable housing officer. And then Frank Sleegers retired in 2007 and I was appointed the zoning officer then. The town merged and I’ve been here luckily ever since. It’s been a great town, it’s been a great experience. If you work in municipal government, it’s a great place to be.

Mark Freda: We’re very lucky to have had you here. Luckily there’s still a lot of diversity in town and people from all over the world and all kinds of backgrounds are here. It’s really a fantastic place. So, okay, you’re in eighth grade, did you say, “Gee, someday I wanna be a zoning officer?” How did this happen?

Derek Bridger: Well, I had gone to college, got a business degree and I was working in commercial lending and residential lending. It was during the eighties when the financial crisis hit. I can remember sitting in my office when that 1987 stock market crashed. From then on I was just kind of at a bank for a year and then they went out of business. I got sick of that and I started doing real estate appraising, commercial and residential. I did that for a while, but I had also gotten my tax assessor’s certification and I worked with Carol Caskey, the former tax assessor in the borough and the township. I was looking to get into that and the zoning officer job or assistant came available and I was just looking for a career change. I wanted some stability. The appraisal business is just, you work 24 hours a day and nobody’s ever happy, you’re never high enough for the value. It just worked out and Frank Sleegers was a great mentor. It’s been a great ride. I’m very happy.

Mark Freda: I remember Frank and Carol. We’ve had a lot of good people come through the two former towns in the current town. Where’d you grow up? Did you grow up in this area?

Derek Bridger: I was born in the Midwest and we moved here. My dad was a chemist for Mobil Oil. I was born in Ames, Iowa. He was at the University of Iowa getting his PhD. He got transferred to Mobil when he got out of college and we lived in Yardley for a year. Then we moved to Hopewell when I was about five. I lived there till I went away to school. I went to school in Virginia, George Mason, then I moved back here in the late eighties.

Mark Freda: You’ve been here long enough to be a local. You have mentioned former borough, former township a few times, and I guess for people listening, the new Princeton, the 12-year-old Princeton hasn’t fully taken the former ordinances from the two former towns and created a new combined set of ordinances. So when you do your job and when people are looking to build an ADU, they have to be very cognizant because the rules are different.

Derek Bridger: That’s correct. It’s a challenge. The code will be harmonized someday. It’s an enormous task and I think we’re leaning towards a consultant to do it. It shouldn’t be something you nip around the edges, it should be a new code. We should look at the master plan suggestions, which was the most robust master plan examination we’ve ever had. Justin Lesko did a great job and the town did a great job. They had a lot of support from elected officials and it’s been a great thing. Follow that plan as the roadmap. But it is confusing for people. There are two R2s. There’s an R2B borough and an R2T township, and the R2B borough is a 10,000 square foot lot area and R2T township is like an acre and a half. So they’re different. I get guys who wanna do it themselves and don’t wanna hire an architect or an engineer. They come in with an application for the former R1 zone in the borough, which is a 20,000 square foot lot area, but the property was in the township and it was like a two acre requirement. It is a headache for people and staff.

Mark Freda: I guess the good news is the town is getting close to putting an RFP out to people that are qualified to come in and create your new zoning code. You almost need a fresh set of eyes to go through it and look at zones. If you have a cluster of a tenth of an acre lots in a half an acre zone, maybe that area should be rezoned to something that fits those lots.

Derek Bridger: Exactly. When the town was consolidated, it was just harmonized—don’t change. But that’s not gonna work. If you have mistakes, let’s fix them. It may take a year or two to do it, but it’ll be done right. Eventually the town will be able to grow in a more smooth pattern and have less confusion with development.

Mark Freda: In the long term everyone will benefit from it, it just could be a little painful going through it. Let me get back to ADUs. Can an ADU be built anywhere in town, any residential zone?

Derek Bridger: Yes, and it’s only if you have a single family house. A lot of people have a two family and they wanna do an ADU or a three family, but it’s only permitted as an accessory use to a single family. They can be built anywhere in town subject to the zoning on the lot. You need to meet the impervious coverage and the FAR. Obviously these are different setbacks for the ADUs that are a little more lenient than for the main house.

Mark Freda: Does my property have to be a minimum size to do it?

Derek Bridger: No. As long as the ADU complies with the bulk requirements and the FAR and the impervious coverage on the lot, you’re allowed to build it. Impervious coverage is a hot topic with climate change and the flooding we’ve had in the last 10 years. If you add more than 400 square feet of net new impervious coverage, then you have to institute a stormwater management system, which is typically a rain garden. That’s another added cost. But sometimes people have an existing garage. They tear that down and you get credit for the existing impervious because it’s net new.

Mark Freda: It makes sense to have a professional help you figure this out.

Derek Bridger: It does. It pays to hire a professional architect and an engineer because the height is based on the average grade. The height for a one and a half story with a five foot setback is 20 feet, and that’s measured to the peak. Then it’s 25 feet for a two story ADU, and that has to be within the setbacks of the main house. The 25 foot structure cannot be right up against the property line.

Mark Freda: What just so people understand, what do we mean by a one and a half story structure?

Derek Bridger: A one and a half story would be where the floor area of that half structure is 50% of the floor below. There’s an attic definition, which is basically area that’s higher than five feet as measured from floor to rafter. If in excess of one third of the floor below, it becomes FAR. If you have a third of the attic area that’s five feet or higher, but it’s less than a third of the floor below, it’s exempt from FAR. That’s how you see some ADUs that look bigger than 800 square feet because of the attic credit.

Mark Freda: And I guess there are always people that wanna push the envelope and find a way to tweak things.

Derek Bridger: It’s like water. It’ll find the cracks.

Mark Freda: Can an ADU have a basement?

Derek Bridger: It can have a basement. If you have an egress window, I’m gonna count the basement as a habitable room. It doesn’t count as FAR, but if you have egress windows, I have to assume it’s for a reason. If you don’t have a basement, if you have a slab, then you get a couple bonuses. They give you up to a hundred square feet for a utility room on the first floor and 48 square feet for a storage area accessible from the outside. We want to encourage crawl spaces and slabs because basements have a tendency to increase the water table.

Mark Freda: What about parking with an ADU?

Derek Bridger: They’re exempt from parking up to two habitable rooms. But if you have three, then you have to have one parking space. It would be the same setbacks as the main house. It’s gotta be 25 feet back from the front property line or behind the house whichever is less. It can be ingress and egress independently from the main house so you’re not just throwing your car in the existing driveway.

Mark Freda: If I have a garage, how does that impact what I may or may not be able to do with that ADU?

Derek Bridger: People look at garages because it’s an already built structure and you could expand it to make it an ADU to save money. However, I do require that it meet the setback because it’s a garage now with cars going in and out, but once it has a family in it, it’s a different use. You do need a variance for that. Anytime you apply for a variance, I would recommend that people talk to their neighbors first.

Mark Freda: Let’s say that I live in a neighborhood that has a lot of small properties like John Witherspoon where houses are fairly close. How does that impact building an ADU?

Derek Bridger: We’ve seen a few creative ones in the John Witherspoon neighborhood where the average lot size is 30 feet. There are exemptions built into the floor area ratio. For example, you get up to 200 square feet for open porches and a 300 square foot exemption for accessory structures. I’ve seen a few where they built less than 300 square feet so it becomes exempt from FAR. It fills a niche in the rental market for either students or elderly people. It also provides the owner the opportunity to live in the ADU and rent the main house out to stay in town. The small ones are a nice addition to the menu of housing in town.

Mark Freda: Earlier you mentioned rain gardens. Can you explain what a rain garden is and what it’s supposed to do?

Derek Bridger: It’s a method to collect stormwater. It’s a depressed area filled with bio-retention material that has water resistant plants. It’s designed to take the drainage from the house and accept the amount of runoff on the site. The idea is that the rainwater goes into this depressed area, infiltrates back into the ground, and cleans the water at the same time as it hopefully stops the overflow onto neighbor’s properties. We’ve had storms like you couldn’t imagine like Ida and the one in 2018. It’s an important thing. We don’t allow dry wells like we used to because they get clogged up with material and silt. Rain gardens are a better option.

Mark Freda: Well, I think I’m out of questions. Derek, thanks for joining us, this has been great.

Derek Bridger: Thank you. It’s been a real pleasure, Mayor. I really appreciate it.