Do you have a basement from the early 1900s? Does it have cracked concrete floors, an exposed foundation with signs of moisture, and low ceilings? Do you dream of having a welcoming family room, guest bedroom, and bathroom instead? It’s possible!
There are a few main items to consider when evaluating taking on a basement renovation that I have outlined below. Parts of this article are specific to Chicago's building code, but most of it is applicable to any vintage home renovation.
Jump ahead to a section here:
1. Permit
Items #2-5 below relate to the City of Chicago’s building code. Almost any level of work to a basement will technically require a permit from the city. Once you pull a permit, there is a chance that the city will come out to inspect the project. For some permits an inspection is required, other permit types don’t have required inspections, but they may still decide to check in on the project. So once you pull a permit, following the code requirements mentioned below is crucial.
If you decide to take the risk of illegally not pulling a permit, I still recommend following the code as much as possible. Having your basement up to code will help if you plan to sell it someday, and it will make your life easier if you ever get caught by the city for not pulling a permit. Plus, the code is there for a reason, and most code requirements are for the safety and well-being of occupants.
Even if you live outside of the City of Chicago, there is a good chance your municipality has similar code restrictions. Be sure to consult with an architect and do your research before starting a project.
2. Architectural plans
If you are making any changes to the floor plans, adding a bathroom, creating a bedroom, or moving any walls, you will be required to submit architectural plans to the city as part of the permitting process. Note that even if you only need a repair and replace permit, where floorplans aren’t required, an architect can help pull the permit. Architects are typically the best source for understanding local code requirements and evaluating what will be possible in a project.
3. Square Footage
Every lot in the City of Chicago has a maximum limit on how much livable square footage is allowed in the home. For RS3 zoning, one of the more common single-family zoning types, 90% of the lot size is allowed to be finished, habitable space above grade. (Grade essentially means ground level.) Basements do not count as 'above grade' as long as more than 50% of the basement is below grade. For most basements, you won’t need to worry about a renovated basement adding to your total allowable square footage. They are usually at least 50% below grade. If your basement has tall windows, that is a potential sign that more of the basement is above grade than in a typical basement. Consult with an architect if you think it may be more than 50% above grade. Note that unfinished space does not count toward the square footage limit.
4. Ceiling Height
To have a legal living space in the city of Chicago, the ceiling height must be 7’ tall. 7’ is after you add in flooring and a dry-walled ceiling. If your basement is 7’ tall now and has a concrete floor and exposed ceiling beams, it won’t be 7’ tall once you add tile or carpet and drywall on the ceiling. Leaving the ceiling beams exposed is allowed; it is not required to drywall the ceiling. I’ve seen designs where homeowners paint the exposed beams and pipes black or gray as a design element. They save the height that drywall would have taken up. It is harder to insulate the ceiling if you don’t have drywall. Adding carpet, tile, or vinyl plank flooring also isn’t required per code. You can leave a concrete floor and stain it but it’s a less popular choice with homeowners. Note that unfinished space (storage, etc.) does not have the 7’ requirement.
Let’s say your basement is currently 6’6” tall, exposed ceiling and concrete floor aren’t going to gain you 6” of height. Your next option is to dig down. Most older homes in Chicago are built on concrete footings. In the basement, you’ll likely see posts running down the middle of the space. Those posts usually have concrete underneath them. To add ceiling height, the existing concrete floor can be broken, and the soil can be dug down to the base of those footings. Then a new concrete floor is poured at that level. The footings underneath the exterior wall foundation are typically the same height as the footings in the middle of the space. This work can be done without involving an engineer or using additional structural support. If you plan to waterproof the basement and add drain tile (see item #10 below), you will be breaking up the existing concrete floor anyways. Digging down doesn’t add that much additional cost.
An easy step to evaluate whether or not you can accomplish 7’ ceilings in your basement is to have a contractor break open your existing concrete floor in a small area. They can then dig in that area to see how deep the footings go. When calculating your needed ceiling height, keep in mind that when you pour the new concrete floor, it is typically 3-4” thick, drywall is ½” thick, and a tile floor is ½”-¾” thick.
If your current basement is 6’6” tall and you determine that you will only be able to gain 2” by digging down to the base of the footing and re-pouring a new concrete floor, there is still another option. The entire structure can be underpinned, essentially temporarily supported, and new footings can be poured lower than the existing ones. New concrete is poured under the home's outer wall and in the center of the space for the new footings. This type of work requires the assistance of an engineer and usually an additional permit. This option will likely cost at least an additional $75k.
Adding ductwork for central heat and AC also takes up ceiling space. It is okay if the areas with ductwork end up being shorter than 7’. It’s important to consider the location of the ductwork in your plans to minimize disruption to the ceiling height in the most commonly used areas.
5. Light and ventilation
In the City of Chicago, Legal, habitable living spaces require minimum amounts of natural light and ventilation. Your current basement may or may not have enough existing windows to meet the current code requirements. Bedrooms have even larger light and ventilation requirements than living spaces. The city will not allow light and ventilation to be counted from windows that are too close to neighboring buildings. Depending on a home’s side setbacks, the only useable light from the city’s perspective may be from the front and back of the property. An architect can help determine these actual calculations based on your plans for the space.
6. Foundation
Before covering the exposed foundation in the basement, check to ensure it is in good condition and doesn’t need any repairs. It is more expensive to fix moisture or foundation issues after it has been covered with drywall and baseboards. If there are any cracks, have them filled in. If you have an original stone or brick foundation, you can also consider adding a short concrete wall inside of the original foundation to add additional support. Contractors and architects can give advice as to whether or not additional concrete support seems necessary.
7. Support posts and beams
During a basement renovation, it also makes sense to consider replacing any support posts or beams that are not in good shape. Many older homes in Chicago have original posts and beams made of wood. Over time, plumbing leaks and moisture levels can affect the condition of the wood. Deteriorated beams and posts may need to be replaced with steel. Large cracks can cause the need for them to be replaced as well. I have seen many original wood beams and posts still in good condition, so they don’t always need to be replaced.
8. Stairs
Often in older Chicago homes, the stairs leading to the basement won’t meet current code requirements. They may be too steep, too narrow, etc. If you are pulling permits for the project, plan room in the budget for updated stairs.
9. Bathrooms
To add a bathroom to a basement there are a few items to consider.
Adding a bathroom will likely require installing an ejector pump. An ejector pump works to push waste up to the level of the city’s sewer line, usually right below street level. A basement toilet is typically well below street level, so the pump is required to pump waste up.
The existing concrete floor will need to be broken to add drains and plumbing lines. If the basement plans include digging down (item #4), or waterproofing (item #10), it's most cost-effective to do this all at once. Then the floor is only broken and re-poured once.
10. Waterproofing
Maybe your basement has flooded, or it has moisture that shows up on the floor around the edges during heavy rains. Or perhaps you have never seen water on the floor, but the exposed foundation has a white substance that flakes off of it (called efflorescence, a sign of moisture coming through the brick) or shows signs of green or black mold. If you plan to spend the money to finish a basement, I highly recommend properly waterproofing it first. Any moisture issues mentioned above will ultimately lead to mold growth once the moisture becomes trapped by drywall and flooring.
At a minimum, I recommend breaking up the existing floor and installing drain tile and a sump pump. I also advise adding a waterproof membrane around all exterior walls. This work is standard in new construction homes and most renovation projects. If you plan to break the existing concrete to dig down for extra height (as outlined in item #4) then it makes a lot of sense to add the drain tile and sump pump system simultaneously.
Adding a flood control system is going a step further, but the majority of the work for it is outside of the home, so it’s easier to do later on if you continue to have issues after the sump pump work.
If you have lived in your home for 20 years, and have never had any water or even moisture issues, that would be the only scenario where I would recommend considering skipping drain tile and a sump pump. Note that waterproofing a basement is not required per Chicago code in a homeowner renovation.
It may seem overwhelming, but with the right team, your vintage basement can look just like the basement of a new construction home!
*** Please note that I am not a licensed architect or general contractor. Consult with a licensed architect and contractor before undertaking any home renovations.***
Comments