How To Look At A House

McGarry and Madsen's home inspection blog for buyers of  

site-built, mobile/manufactured and modular homes

How do you determine when the house was built?

Sunday, July 22, 2018

Checking the year listed by the county property appraiser is how the age of a house is usually found. But things can get complicated. There are two dates listed: actual year built and effective year built. The first, “actual year built” is when the initial construction was completed. If the house was significantly changed later, then the “effective year built” reflects the updated condition of the house after a remodeling or addition occurred.

    For very old houses, the property appraiser’s date  is nothing more than the earliest record of it appearing on the modern tax rolls--which may not even be remotely close to the year built. Sometimes an old house will be moved, and the property appraiser’s information shows only when it arrived at the new location. And, once in a while, the official year built is obviously just wrong. So there are multiple  other ways that a determined sleuth can find the approximate age of the home:

•• The Sanborn Fire Insurance Company created detailed maps of cities around the United States beginning in 1852, showing the outline of each home in each block of a neighborhood, and updated every few years. They were created to help insurance agents assess the degree of fire hazard for each location. Over 130 Florida cities and towns were mapped, with the earliest depicting Cedar Key in 1884, and a small section of the Key West map is shown below. 

    The company went out of business long ago, but it’s maps are a valuable historic record. The age of a house can sometimes be determined by the date of the Sanborn map where it’s outline first appears. The University of Florida maintains a collection of early Sanborn maps of Florida cities which can be accessed online at

•• The type of building components still in place in the home can tell a story about the age. Electric wall receptacles have a technological timeline, for example. If the receptacle has only two slots, and they are both the same height, it is non-polarized, and pre-1920. When the receptacle has two slots and one is slightly taller than the other, it is polarized, and pre-1960. If the receptacle has two slots and a round hole below, then it is a grounded receptacle and post-1960.   Asbestos siding, terra-cotta drain pipe, and linoleum floors each peg a house to a particular era if they are original to the construction. OSB (oriented strand board) was not developed until the 1980s and, at the other end of the timeline, indicates that a house is newer.

 •• The architectural style of the home and construction type tell their own story. Heavily textured stucco over wood lath on the exterior walls dates a home to the 1920s or 30s, and a low-slope gravel roof on a long and narrow home with minimal trim means it’s from the 1950s or 60s.

•• Check the electric meter, if original. It will be marked with a date of manufacture.

 •• And last, pulling the lid off the toilet tank and looking for a date stamp underneath is a favorite technique among real estate appraisers. 

   After looking at thousands of houses, a home inspector develops an intuitive sense for the age of a house, along with an understanding of what is the original part of the home and where the later additions begin. Plus, every once in a while, we come up with evidence that a home could not possibly be as young as it is portrayed to be. For example, we recently proved that a home indicated by the seller to be built in 1995 was actually a much older home that was moved to the site and remodeled in that year. Remnants of knob-and-tube wiring in the crawl space (not used after 1950) gave it away.

   If you want to learn more about investigating an old home to learn more about how it was built, sorting out the older and newer parts, and the lifestyle of the original owners, we suggest reading an article by an architectural historian for the National Parks Service, entitled “Understanding Old Buildings - The Process of Architectural Investigation.” Here’s a link to it:

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  To learn more strategies for getting the best possible home inspection, here’s a few of our other blog posts:

How can I make sure I don't get screwed on my home inspection? 

How thorough is a home inspector required to be when inspecting a house?

Should I trust the Seller's Property Disclosure Statement?

Can I do my own home inspection?

How can homebuyers protect themselves against buying a house over a sinkhole? 

The seller gave me a report from a previous home inspection. Should I use it or get my own inspector? 

    To read about issues related to homes of particular type or one built in a specific decade, visit one of these blog posts:

What are the common problems to look for when buying a 1940s house?

What are the common problems to look for when buying a 1950s house?

What are the common problems to look for when buying a 1960s house?

• What are the common problems to look for when buying a 1970s house?

What are the common problems to look for when buying a 1980s house?

What are the common problems to look for when buying a 1990s house?

What problems should I look for when buying a country house or rural property? 

What problems should I look for when buying a house that has been moved?

What problems should I look for when buying a house that has been vacant or abandoned?

What are the most common problems with older mobile homes?

What do I need to know about a condo inspection?

What are the "Aging In Place" features to look for when buying a retirement home?

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