Digging into your home's past can be fun, but it can also help you make aesthetic decisions and avoid costly mistakes. Here are potential stumbling blocks when renovating an older house:

1. Not researching the history

Conduct your own research ahead of time. Look at old maps from your local historical society or online through the U.S. Geological Survey, educate yourself about which materials are right for your home's climate and setting, and visit a museum that has period rooms based on your home's era. Look back at the real estate listing, if you can, because many agents of older properties include a backstory and ownership history.

2. Trying DIY on the wrong project

In this age of HGTV shows and YouTube tutorials, many homeowners consider bypassing a professional for what they think will be easy alterations. But fixes in older houses sometimes are more complicated than those in newer construction, and mistakes can cost more than an architect's fee.

Stripping or removing paint especially requires caution: Paint in older houses can contain harmful substances such as lead.

"Cosmetic improvements that don't affect any systems are usually safe DIY projects," says Naomi Miroglio of San Francisco-based Architectural Resources Group. But "if finishes need to be removed or walls opened up, it should be left to a professional."

She points to replacing bathroom faucets, typically an easy DIY project in newer homes, as an example of what not to do in older homes. "Often the cutouts in the porcelain for the faucet and knobs are at different dimensions than current faucet assemblies. One has to look for salvage pieces or custom-order them." Miroglio also recommends leaving electrical and plumbing work to the professionals because of the safety risks.

3. Adding pristine new elements

Owners of older homes will either refinish original elements, such as the woodwork, or install reproductions. Juxtaposed with the worn details, however, these pristine copies or gleaming finishes can look out of place. Worse yet, some of the materials used in decorative reproductions lack the quality and durability of the original materials.

"Some contractors think it's more trouble to save decorative pieces than work around them," Miroglio says. "You might have four beautiful column capitals and one bad one. They'll suggest replacing them all to look the same. Often it's a cheaper material inside, like Styrofoam."

Or, she adds, they'll strip and re-stain the wood floors, resulting in an overly pristine appearance that's lost a lot of character. Instead, she recommends retaining some of the aged look. "It's arrested decay: You stop it from decaying but avoid making it look brand-new."

4. Installing vinyl windows

Older, unrenovated homes aren't going to win any awards for energy efficiency. So many homeowners target those drafty wooden windows for replacement. But architects caution against choosing modern vinyl options.

"Even though a wood window will cost a lot more than vinyl or aluminum, the wood is worth the investment because it can survive a hundred years," New York architect Anik Pearson says. "Vinyl clad won't last for more than 10 or 20 years, and metal clad is better than vinyl but in arid climates."

Miroglio says, "We work hard with homeowners to understand how you can weatherize wood double-hung windows. Maybe they just need new putty."

5. Tiptoeing around technology

Implementing modern technology, such as home automation, is a hot topic. Fortunately, the nature of WiFi means there's no need to rewire the house or install high-tech devices out in the open. "There's no reason a thermostat has to be in plain view. You could keep it in a closet and use a hidden sensor that no one sees," Pearson says.

6. Being afraid to remove walls

Architects are divided on the idea of opening up historical homes. Older floor plans can clash with modern-day living, and a well-renovated and expanded kitchen, for example, can increase the value of most properties. And an open concept might serve some families better than a compartmentalized layout.

"It's perfectly acceptable to knock down walls," Pearson says. "There is a history of people altering structures, adding on wings at different times."

But Fauzia Khanani of New York's Studio Fōr warns that it's possible to go too far in the hunt for an open concept. In older homes, "each room had a specific function and there was a transition, whether doors or a threshold." She adds: "There is something about each one of those spaces that made it unique, so taking that away takes away something from the house."

7. Adding square footage

Most architects agree that additions, when done with care, are acceptable. But not all additions are tasteful. Khanani points to an awkward — but functional — addition to a renovated Victorian in New York's Hudson Valley. It "looked like an appendage and not part of the original design intent," she said, despite its stylistically matching the finishes and details of the rest of the house. Khanani removed it entirely and uncovered a beautiful bay window with a window seat, which she restored. Then, to reclaim the square footage lost, she designed a similarly sized addition on the back side of the house.