Basement Renovation Cost Estimates

In general expect to spend anywhere from $10K to $100K to renovate a basement, again depending upon the features, and whose doing the work. For a 40’x30’ DIY basement remodeling project that includes a bathroom, on average you can expect a basement renovation cost of about $25K to $40K. This is assuming you’re subcontracting out the plumbing, electric, drywall and flooring installation.

With any basement renovation cost estimate there are a number of key items that should be broken out and included in the estimate. First and foremost, there should be cost estimates for moisture control and radon abatement. The basement should be first tested for moisture and radon concerns and then appropriate mitigation solutions should be costed out in the basement remodeling estimate. Ignoring either of these issues could result in an unhealthy living space environment. Moreover, moisture issues can lead to aesthetic and physical damage to the renovated basement and home. In many cases simply applying a waterproof sealer over the basement walls and concrete slab is sufficient for mitigating moisture concerns.

In other cases gutters or a perimeter foundation drain may be required. Basement waterproofing costs can vary from a few hundred dollars to a few thousand. With radon gas, a ventilation system may need to be installed. Costs for a radon ventilation system could cost around a thousand dollars.

Second, framing should be broken out separately. Basement wall framing can be fairly complex as soffits are often needed in the ceiling to hide plumbing pipes and duct work.

In addition, basement floors, walls, and ceilings heights are typically not straight and plumb. Thus basement walls often need to be stick built, which adds time and money to the basement renovation costs. Third, electric and plumbing work should each be costed out as separate line items. If your basement renovation plans do not include a bath, kitchen or wet bar, you can dramatically cut your basement renovation costs. Electric, however, is a must with any basement renovation project. Make sure the electrical cost estimate includes the use of Ground Fault Circuit Interrupters (GFCI) and Arc Fault Circuit Interrupters (AFCI). GFCIs are a must wherever there is potential for moisture conditions, and AFCI’s are required in all residential living spaces.

Forth, make sure your basement renovation cost estimates include a separate line item for insulation. Even though the cement basement walls are thick they need to be insulated. Rigid foam insulation is often used on basement concrete walls. In other cases 2×4 walls are built adjacent to the walls and rolled or batt fiberglass insulation is installed in the 2×4 walls.

Moreover, you may want to build an effective crib network on the floor of framing material, with rigid foam insulation installed between the framing members, to provide floor insulation.

Seventh, make sure to visit your local building inspector prior to starting your basement remodeling project. When you visit him or her, make sure to bring your basement renovation cost estimates along with your plans. The inspector will want to review them prior to granting you a building permit.

Finally, when soliciting contractor bids, make sure to get basement renovation cost estimates from several remodeling contractors so that you can compare prices and schedules. Don’t hesitate to question any of their cost proposals and assumptions, and feel free to negotiate with them. Lastly, make sure to check multiple references with each basement remodeling contractor you are seriously considering.