The renovator

Charlie Allen restores period homes back to their original beauty. (JONATHAN WIGGS/GLOBE STAFF)

Calling Charlie Allen a general contractor is a bit like calling an archeologist a ditch digger. It's true, but misses all the subtlety and craft. Allen renovates period homes, undoing the damage that's been done over the years - sometimes centuries - by well-meaning owners and builders, and updating decrepit systems to make them functional and safe. And he does all this while trying to keep the beauty and integrity of the home intact. One of his favorite moments? Peeling back the aluminum siding from a home to see what treasures lie beneath. "That," he says, "is really fun."

Q. What's the biggest challenge in renovating and restoring a period home?

A. Money. What do I mean by money? This is the real world. I give the house a voice. We have to do what the family needs and what they can afford. So the tension is between what the house needs and what the house wants, and what can be afforded is a very big challenge. How to not compromise, but how to get what a growing family needs with the budget. We rarely work for people who have enough money to do everything they want to do.

Q. You moved here from Washington state to go to Harvard. Do you come from a family of renovators?

A. I come from a Western family or a Western tradition that is not so aware or concerned about class. Everybody does hands-on things. We're talking about the knitters, the quilters, the build-your-own housers. It wasn't until I got here that people thought having dirt under your nails wasn't a good thing. No, they're not builders, but my father built his own house.

Q. You must live in an old house yourself.

A. I live in an 1840s Greek Revival workers cottage on Cottage Street [in Cambridge]. It had been empty for 25 years. It was in deplorable shape. We worked on the living room, the dining room, all the original windows, casings, stairs, moldings. It still looks the way it did in 1840. It has all modern systems, but the look is original.

Q. What's the biggest mistake people make when trying to renovate a period home?

A. Honestly, not having a plan. Just pulling at the loose thread on things.

Q. What was a particularly challenging project?

A. We had an awful lot of fun with the challenge of our office. It's in an 1899 Flatiron building in Cambridge. It only has 250 square feet on the first floor. And it had nothing in the basement. We essentially renovated the storefront and then we did the basement. We copied the wainscotting and found old newspaper clippings about the opening of the building and got old windows and doors. That was a big challenge to do while you're running a business.