Historic homes overflow with charm, but maintaining them requires due diligence. Here are some tips from highly rated Angie's List service companies specializing in historical renovations:

More time, more money

Replicating old-world craftsmanship requires more money. "Everything has to be custom-made," says Peter Martin of highly rated Martin Renovation Group in St. Paul, Minn. "Between the money and the time it takes, you have to be committed to the house."

Embrace the red tape

If your home is listed on a historic register or located in a preservation district, check with those offices about special project requirements. "Get a sense for what hoops you'll have to jump through to get the work done," says Nick Falkoff of A-rated Auburndale Builders in Auburndale, Mass. "Most likely, if you want to remodel, you'll have to follow their guidelines."

Expect the unexpected

The older a home is, the more likely it is that previous owners have embarked on their own renovations. "You're opening up Pandora's box," says Daniel Steinkoler of highly rated renovator Superior Home Services in Washington, D.C. "It's important to budget for surprises." Falkoff recommends setting aside 10 to 20 percent of your project budget for surprises.

History's headache

Before the dangers became well-known, asbestos and lead paint were common building materials. "Almost every house built before 1971 has lead, unless it's been removed," says Tim Miller of highly rated Tim Miller Contracting & Design in Portland, Ore. Ask your contractor what precautions or abatement steps they will take if they find toxic materials in your old house.