In both construction and renovation, no matter what type of work is involved, estimating costs is almost a profession in itself; the experience and qualifications of the estimator are critical.
Many estimators use the cost per square foot method.
This involves measuring everything that can be measured (in linear, square, or cubic feet) and then converting those measurements into price/labor based on quantities. For example, the floating wood floor you choose costs $2.50/ft2 to install. Your basement floor is 400 square feet so that it will cost 400 x $2.5, or $1,000 for this part of the renovation.
In cases where the foundation is affected, different tradespeople will need to be involved in the project. In this case, the full-cost method may be preferred. This method starts with identifying all the tasks to be carried out, trade by trade, and the list of all materials required for the renovations. The estimator must then be familiar with the specialties and the labor costs related to these specialties.