Find out how to determine your home's age. Knowing when your home was built is useful information, because it can help you be aware of problems common to homes built in that era. Get tips on how to play detective and figure out the age of your home using public records and gathering clues from building materials.
LESLIE: Well, as long as there have been homes, there have been home repairs. But if you know the age of your house , however, problems common to homes built in that era can sometimes be avoided.
TOM: Or at least you’ll know what to expect. Kevin O’Connor  is a guy who has seen more than his fair share of the secrets old homes can share. He is the host of TV’s This Old House  and is here with some tips on how to figure out the age of your own home.
KEVIN: It’s great to be here. Thank you for having me.
TOM: You know, Kevin, after spending 20 years as a professional home inspector, I got pretty good at knowing what might be wrong with a house before I even sort of walked in the door. And that wasn’t because I had mystic abilities but more because I had seen the same defects in houses of the same age time and time again. I’m sure that you have seen much of the same. So what are your favorite ways to kind of date a house  before you tear into all of those fantastic renovations?
KEVIN: Well, my favorite way is to show up with Tom Silva.
TOM: That’s your secret weapon, right?
KEVIN: That’s my secret weapon because that guy, like you – I mean if you do it for 20, 30 years – he’s seen it all and he’s just got an eye for these things. If you don’t have that magic eye, I would say one of the first things you want to do in compiling a history of the house is just identify the era in which the structure was built.
And you can do that, oftentimes, with the help of an architectural book or two. Most homeowners are probably going to be able to narrow their house down to a core style that’s common to their area. And that’ll give you a pretty broad range of the timeframe when it was built.
TOM: So you can get it narrowed down to the era. And also, of the area of the homes that you’re in, a lot of times you find that – what we think of as a modern development today of a bunch of two-story Colonials, back then it was a bunch of Victorians, right?
KEVIN: Yeah, it’s amazing. We did a project in Brooklyn and these guys had all these brownstones that we loved that we think are historic houses . These were done by developers. This was just track housing for the workers in Manhattan. They’d buy a block, build eight of them at a time and then repeat the process.
So, yes, you’re right. You can actually see clumps of these houses being built from one period to the next and it can really narrow it down.
TOM: Now, what about public records? There are a fair amount of records that are out there if you know where to look.
KEVIN: Well, there’s a lot out there and they can actually tell you a lot about your house. So, think about visiting your local building department, maybe your tax assessor or the Register of Deeds Office. And there you’re going to find things like deeds or maps, plot plans or even building permits. And they can tell you a lot about your house. Each one of those things is a piece of paper and has probably got some history on your home.
I’ve heard about insurance companies, that they actually have maps that go back to, say, the mid-1800s that they’ve kept to catalog buildings in your area. If you can get your hands on those, you’re probably going to find a wealth of information just there.
TOM: Yeah. And that building-permit tip is a really good one because it’s amazing when you get your hands on that file – and it’s all public record, so you can ask for anyone’s building permits  that you’d like. And it could be your neighbor’s, whatever. And you can see the history of that house through those permits and see what additions were made and get the dates and all of the work that was done. There’s just a lot of information there that’s literally at your fingertips if you just go dig up the files.
KEVIN: Yeah, it’s one, big, long chronology of your house, oftentimes.
TOM: Now, let’s talk about some of the ways that you can date your house  based on what’s in the house. Certain improvements, certain wiring techniques, plumbing techniques are tied into certain dates, right?
KEVIN: Yeah, this is great and this is why I love having a guy like Tom Silva by my side. Because when we dig into these houses, we find these things, right? Knob-and-tube wiring. We talk about these things all of the time and what you have to do to replace them or fix them. You’ve got steel plumbing pipes.
But the reality is is that these things were materials used in very specific periods. So knob-and-tubing or steel plumbing pipes, they’re generally dated to the 1900s to the 1940s. Those small, fuse-type electrical systems or …
TOM: The ones that people always put coins behind?
KEVIN: Exactly. Or plaster-and-lath, right? You ever dig into one of those things? Or have you ever seen vermiculite insulation? Well, those things, well, they were common in 1940 to 1960, so they’ll tell you a little about your house.
And hey, remember avocado appliances?
TOM: Ah, who can forget?
KEVIN: Right? Yep. That’s 1960s or 1970s, the dark era of design. They’ll tell you something, too.
TOM: Absolutely. Now, there are actually places in your house where dates are physically recorded. I think this is always really fun. You can look inside of toilets and see when the toilet was manufactured. And you can look under sinks. And sometimes, the dates are actually cast right into it.
KEVIN: Stamped there by the manufacturer. It’s like an archeological dig. It’s going back to Pompeii and saying, "Hey, look at this toilet. It was actually made in 1915." That information is there if you know where to look.
TOM: And you know what? It was done right before it was installed in the house because they didn’t stockpile those plumbing fixtures back then.
KEVIN: No, probably not.
TOM: They made them and installed them. So if you’ve got a date that it came off the assembly line, you can bet your home was built pretty close to that time.
Kevin O’Connor, the host of TV’s This Old House, that’s a really fun topic. Thanks so much for stopping by The Money Pit and sharing a little house history with us.
KEVIN: My pleasure.
TOM: And This Old House and Ask This Old House are brought to you by State Farm. Like a good neighbor, State Farm is there.