You may have had a figure in mind for what you could afford when you began to develop your remodeling wish list. You may even have shared that number with the designer when you sat down to discuss your remodeling goals and ideas. But for every line and symbol the designer saves on the CAD drawings, there should be a cha-ching sound with the keystroke. By developing a parametric estimate based on concept plans - that is, an early draft before details have been fully resolved - you’ll find out where you’re going before you get too far down the road.

 

Parametric estimates are generalized cost predictions based on data for various types and elements of construction, material costs and labor rates in specific areas of the country. They can be very general, as in “residential construction in the Washington, DC, Metro area costs between $100 and $150 per square foot.” While this fact is interesting, it is not particularly helpful for estimating with any accuracy the cost of the project you may have in mind.

 

What accounts for the large spread between the lowest and highest prices per square foot in parametric quote above is that it takes into account many different construction possibilities. For example, the lower end might represent the cost for an addition built over an 8-inch block crawlspace while the upper end might represent an addition built on 10-inch thick reinforced concrete basement walls that are 9 feet tall. A component of the low-end price might be vinyl windows with conventional glazing, while the high-end figure might include wood windows with gas-filled, low-E insulating glass. Roofing at the low end might be 15-year asphalt shingles while at the high end it might be concrete tiles with a lifetime guarantee. Finish flooring at the low end might be some combination of resilient sheet and synthetic fiber carpeting; at the high end you might see hardwood flooring and ceramic tile in the baths and kitchens. Remodeling costs for kitchen at the low end might include stock thermofoil over particleboard cabinets - at high end, custom cabinets of solid hardwood.

 

To begin creating a parametric estimate, you need some basic facts about the major cost components - most of which can be found on the plan view of your project and in certain construction detail views. How big is the space in square feet? How many linear feet of foundation walls? What are the material specs and how are they to be assembled? How many square feet of exterior siding? What’s the siding material? How many square feet of roofing? What’s the finish roofing material? How many windows? How many doors? For kitchens: What material and door style for cabinets? What countertop material? How many linear feet of base cabinets? How many of wall cabinets? Which appliances will be included? Standard models or premium? Same questions for bath fixtures: which ones will be included? What general price points?

 

You can take your project drawings to a professional construction cost estimator, who for an hourly fee will develop an objective parametric estimate. Or, if you’re comfortable with software programs like Microsoft Excel, you work up your own estimate with any of a number of estimating programs with built-in databases of construction costs for typical assemblies in various regions of the U.S.

 

Developing a cost estimate along with architectural plans will help to keep the design on track and your goals within reach - even if they need to be adjusted a bit mid-course. It will also help you to determine your financing needs and provide backup for a loan application And having an independent cost estimate in hand will also help you evaluate contractor bids and give you some leverage in contract negotiations.