Finishing a Basement
Updated: Apr 9
Your unfinished basement can provide large living space potential. Finishing it can improve property value and be a welcome alternative to the disruption of an addition, and may be the only viable option for additional space on small lots. Photos by In-House Photography.
Here are the top things to consider before finishing a basement. First, and most importantly: what is the your intended use of the space? The spacious finished basement above & below in Montclair, NJ includes an entertainment & media area, large bar, laundry room, powder room and a billiard room (MGR Construction Inc.,)
The basement (below) includes a family room with walk-out french doors and wood stove (South Orange, NJ, Tillou Construction).
Once space is allocated for utility and storage, how much room will you have for other areas? These elements are likely already down there, and homeowners will want to continue to allocate a good deal of space for this. Furnaces, boilers, HVAC units and water heaters all require clearances for servicing and exhaust space. Also, gas appliances require more venting than electric appliances and cannot pull air from bathrooms or bedrooms. If there is not enough space for proper internal venting, appliances may need to be replaced with direct vent versions which add additional costs.
Is your laundry located in the basement? Will it stay there? Clients often ask to renovate a basement laundry. Although I often recommend moving to an upper floor, spacious basement laundries definitely work well for some clients. This large basement laundry room in Summit was the perfect size and location for our client (Kasdan Construction management)
Play-room/Entertainment Rooms work quite well in basements given the desired lack of light for best viewing of screens. Often mini-bars, kitchenettes and bathrooms are included in the plans in order to make the entertainment experience complete without having to trek upstairs to add ice to the soda, make popcorn or take a bathroom break. Will there be a couch in the room? If the answer is "yes", they someone will likely be sleeping on the couch at some point, so I generally recommend ensuring egress requirements similar to bedrooms. This basement entertainment room (below) in South Orange has the advantage of enabling a wheel-chair ramp from the lower-level garage to other areas of the basement. (Murphy Construction, Nu Interiors)
When clients want exercise rooms, I ask about what kinds of exercises or equipment they will be using. Most treadmills and Smith racks for weights recommend an 8 ft minimum ceiling. If the ceiling is lower, stationary bikes, benches for weights, and mats for floor exercises may be an option.
Is a new bedroom part of the plan for the basement? Many municipalities do not allow bedrooms in basements. Egress during fire is a primary reason. Code requires a minimum of two (2) ways out of a bedroom. In basement bedrooms, egress options must be provided, often via secondary doorways to exterior stairs or via egress basement windows. These basement egress windows have the additional benefit of adding more light to a bedroom.
The photo (right) shows a new egress basement window - this one in a media room. (Kasdan Construction Management). Building codes often also require a certain amount of natural light and venting from windows in bedrooms. Light and venting can be provided mechanically, but natural light and venting are preferred.
Does the basement have any existing bathroom fixtures? Full or half-baths can be very useful. The basement bathroom (right) was one of my favorites; there was a change in the floor level between one side of the basement and the other - we used that change in floor level in the shower to create a bench. (Kasdan Construction Management)
Next, what is the condition of the existing basement? Homeowners should be prepared to solve any problems prior to investing any money in renovations.
How dry is the basement? Have water issues been resolved via sump pumps, French drains, exterior grading etc.? If your home's basement is considerably below your area's water table, keeping a finished basement dry may be a constant struggle.
What is the head height in the basement? Although NJ code allows for the refinishing of basements that are under habitable height (7 ft), there are specific head-height requirements for plumbing fixtures and other situations. Basement HVAC ducts, water pipes/drains and beams can further reduce the head height. Homeowners should consider the legal and safety risks of having family members and guests occupy space where head injuries could be encountered from low ceilings, beams or pipes. The floor can be lowered, but it is an expensive alternative requiring new footings for any supporting columns and modification (if not complete re-build) of any stairs. Lowered floors also put the finished floor closer to the natural water-table beneath, which may introduce water problems that did not exist before.
Given the basement is the lowest floor, it generally houses and protects the structural elements that hold up the rest of your home. Are these in good shape? Prior to finishing (and possibly concealing) structural elements, it is important to make sure these are structurally sound.
Where is the main plumbing waste/soil stack? For any intended plumbing - from laundry to bathrooms or mini-bars - adequate plumbing venting and draining must be provided. Locating the main soil stack and developing a plan to enable plumbing drains to have adequate gravity pitch to reach the main soil stack is critical when determining locations for new plumbing appliances. If situations where the main drain is higher than the basement floor, a sewage ejector pump may be an option, but this would add additional expense and take up a bit of space.
Have hazardous materials been remediated? This will need to happen either before the project starts or included in the scope of work. Given most of our clients' homes are older homes, there may be asbestos in the basement - either as floor tiles or encasing furnace pipes. Also, though not restricted to basements, homes built before 1978 likely will have lead paint somewhere. Construction crews should use LeadSafe practices when remodeling areas with lead paint.