Complete Guide to Attics and Basements: Projects: Getting Started: Evaluating Your Basement

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Basement headroom is often limited by beams, ducts, pipes, and other elements. Typical minimums for ceiling height are shown here: 7½-ft. for habitable rooms; 7 ft. for bathrooms and hallways; 7 ft. for obstructions spaced no less than 4 ft. apart.

The two things that put an end to most basement finishing plans are inadequate headroom and moisture. Begin your evaluation by measuring from the basement floor to the bottom of the floor joists above. Most building codes require habitable rooms to have a finished ceiling height of 7.5 ft., measured from the finished floor to the lowest part of the finished ceiling. However, obstructions, such as beams, soffits, and pipes, (spaced at least 4 ft. on center) usually can hang down 6’ below that height. Hallways and bathrooms typically need at least 7-ft. ceilings.

While it’s impractical to add headroom in a basement, there are some ways of working around the requirements. Ducts and pipes often can be moved, and beams and other obstructions can be incorporated into walls or hidden in closets or other uninhabitable spaces. Also, some codes permit lower ceiling heights in rooms with specific purposes, such as recreation rooms. If headroom is a problem, talk to the local building department before you dash your dreams.

If your basement passes the headroom test, you can move on to the next issue: moisture. For a full discussion on this critical matter see article Dealing with Basement Moisture. Be aware that moisture problems must be corrected before you start the finishing process.

A well-built basement is structurally sound and provides plenty of support for finished space, but before you cover up the walls, floor, and ceiling, check for potential problems. Inspect the masonry carefully Large cracks may indicate shifting of the soil around the foundation; severely bowed or out-of-plumb walls may be structurally unsound. Small cracks usually cause moisture problems rather than structural woes, but they should be sealed to prevent further cracking. Contact an engineer or foundation contractor for help with foundation problems. If you have an older home, you may find sagging floor joists overhead or rotted wood posts or beams; any defective wood framing will have to be reinforced or replaced.

Your basement’s mechanicals are another important consideration. The locations of water heaters, pipes, wiring, circuit boxes, furnaces, and ductwork can have a significant impact on the cost and difficulty of your project. Can you plan around components, or will they have to be moved? Is there enough head room to install a suspended ceiling so mechanicals can remain accessible? Or, will you have to reroute pipes and ducts to increase headroom? Electricians and HVAC contractors can assess your systems and suggest modifications.

Aside from being dark and scary places, unfinished basements often harbor toxic elements. One of the most common is radon, a naturally occurring radioactive gas that's odorless and colorless. It’s believed that prolonged exposure to high levels of radon can cause lung cancer. The Environmental Protection Agency has free publications to help you test for radon and take steps to reduce the levels in your house. For starters, you can perform a “short-term” test using a kit from a hardware store or home center. Look for the phrase “Meets EPA requirements” to ensure the test kit is accurate. Keep in mind that short-term tests are not as conclusive as professional, long-term tests. If your test reveals high levels of radon, contact a radon specialist.

Another basement hazard is insulation containing asbestos, which was commonly used in older homes for insulating ductwork and heating pipes. In most cases, this insulation can be left alone provided it’s in good condition and is protected from damage. If you fear the insulation in your basement poses a hazard, contact an asbestos abatement contractor to have it evaluated or safely removed.

Also check the local codes for exits from finished basements—most codes require two. The stairway commonly serves as one exit, while the other can be a door to the outside, an egress window, or a code- compliant bulkhead (an exterior stairway with cellar doors). Each bedroom will also need an egress window or door for escape.

Stairways must also meet local code specifications. If yours doesn’t, you’ll probably have to hire someone to rebuild it. See article an overview of typical staircase requirements.

As a final note, if you’re planning to finish the basement in a new house, ask the builder how long you should wait before starting the project. Poured concrete walls and floors need time to dry out before they can be covered. Depending on where you live, you may be advised to wait up to two years, just to be safe.

Figure: Tips for Evaluating Your Basement: Rerouting service lines and mechanicals adds quickly to the expense of a project, so consider your options carefully.

Old insulation containing asbestos poses a serious health risk if it's deteriorating or is disturbed.

Figure: Weakened or undersized joists and other framing members must be reinforced or replaced. Minor cracks such as these in masonry walls and floors usually can be sealed and forgotten, while severe cracking may indicate serious structural problems.

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Updated: Wednesday, August 10, 2011 5:36