In shorts and a tee shirt, Mark Olshansky pauses on his way through the Renaissance of Ravenswood condo development to steady a molding while a carpenter cuts it. He continues into the model unit, where his sister, Marla Mason, is showing off a real estate ad she designed.

Mason and Olshansky are not flunkies hired by a big-time developer with offices in the loop. The brother-sister team are co-developers of this 18-unit vintage conversion at 4452 - 4458 N. Whipple. They take a hands -on approach rare among today's developers, handling construction crews, marketing and sales themselves -- and even steadying the occasional molding.

"If you're willing to work hard enough, you can get most things done in-house," Olshansky says. "we never consciously sat down and divided up the labor, but we each gravitated toward the things we do best. She has the design sense, and I can get it built."

Mason has a background in interior design and Olshansky, who left the sporting goods industry in the late '80s, runs his own construction crews. They formed JMM development to rehab rental properties and then moved on to condo conversions, including a recent success with the nearby Vines of Ravenswood, a 12-unit conversion they sold out in about three months.

Their projects have been concentrated in Ravenswood, the quiet Northwest Side neighborhood where both developers live. Their units have sold quickly because of practical, creative designs and an intimate knowledge of their niche.

"We try to think in terms of large, volume rooms," Olshansky says. We're sick of chopping units into small rooms because people don't live that way. Another thing we've done, at a customer's request, is build some master bedrooms with enclosed sun porches off of them. We groaned when he suggested it, but then other buyers saw the design and liked it. I guess romance isn't dead"

Mason and Olshansky pride themselves on knowing their neighborhood and what their buyers want. About 90 Percent of JMM's customers are first-time buyers looking for value and a total package, Mason says.

"The people in our price range don't have a couple of extra thousand to spend after they move in," Mason says. They want turnkey units where everything is included. We have found that people go to models and think that's what they're getting, but there are $30,000 of upgrades in the models. Our models are standard."

Buyers at The Renaissance of Ravenswood can choose their own cabinets, floors coverings, counter and other items, but everything -- Including the actual washer and dryer, not just hookups -- are included. The two bedroom, one bath units feature hardwood and ceramic floors throughout, large kitchens, sun porches, security systems, individual heat and air conditioning, great rooms, Merillat cabinets, Moen fixtures, miniblinds, new back porches' and secured deeded parking. Units are priced from $109,900 to 129,900.

The gut rehab of the building, including all new electrical, plumbing and heating systems, has been overseen by Olshansky.

"We really try to concentrate on the little things, like having a window over the sink for when you do dishes, making sure the soffits look good, giving people a breakfast bar."

For more information, call 773-583-5834.