Comment: We are seriously planning to purchase a twenty five-year old, two-bedroom, one-level ranch home, but it needs an additional bedroom/den/office for our needs. Before we make an offer, we need a reasonable estimate for adding about 200 sq ft addition. The exterior land is flat, with sufficient space for this addition and setbacks. Will need lap siding, sloped roof tagged into existing roof, with 3-tab asphalt shingles, gutter + one downspout, connect witih existing drain, a cement foundation with crawl space, foundation vents, sealed interior, insulated walls, sheetrock, insulation above ceiling, below floor, one dbl-paned vinyl dble hung window, generic carpeting over T&G subflooring, extension of forced air ducts and electrical, but no plumbing. Standard closet w/sliders. What should we budget for this 200 sq ft space? We need a reasonable figure very soon.