So the basement has made it clear it won’t go quietly. Current score: Basement 3, John and Sherry 1. Thankfully we love a challenge. Here’s an update on our underground overhaul and where things stand.
Many readers asked for more of the nitty-gritty: not just a shopping list or budget breakdown, but the actual thought process behind prioritizing functions, sketching a workable floor plan, and dealing with the pitfalls we encountered. We won’t spare any details as we transform our bleak, cobweb-filled basement into a finished, functional storage room—one that can safely house extra furniture, bikes, accessories, and seasonal decor without spiders and mildew. First, a quick orientation: the basement sits directly below the sunroom at the back of our house and is accessed by a short brick stairway.
At 19′ x 13′, it’s a generously sized room—the largest in our house along with the sunroom above. Unfortunately, that’s where the positives end. The room presents several major problems: recurring flooding after heavy storms, an overwhelming spider population, and pervasive mildew that attacks walls, floors, and anything stored down there. We also have a large, unattractive water heater sitting in the middle of the space…
…a radon mitigation pipe to work around, a strange trap door leading to the crawl space…
…and only two tiny windows to introduce light into the cinder-block room. Not an ideal starting point.
Still, we’re committed to turning those cons into usable features or at least minimizing their impact. Because the room has a separate exterior entry, it’s unlikely to become primary living space. Instead, we’re focused on creating a highly functional, organized storage room with a built-in look, not a hodgepodge of wire shelving and warped boards. Before we moved onto layout and storage solutions, we had to eliminate the issues that made the room unworkable: the wetness and widespread mildew, both symptoms of trapped moisture.
Our research identified three essential steps to tackle the water and mildew problems:
- Eliminate the existing mildew.
- Seal the cinder block walls and concrete floor so they no longer absorb water during storms.
- Prevent recurrence by using a dehumidifier (ideally Energy Star rated to keep operating costs down).
The most recommended product for sealing cinder block and concrete basements is Drylok—a thick, paint-like sealant. Applied in two heavy coats, it blocks moisture for years. The can even claims it can withstand the pressure of a 22-foot-high wall of water. It’s effective, but not cheap.
Thankfully, our participation in the True Value DIY Blog Squad helped offset costs. We discovered we needed nine gallons of Drylok at roughly $25 per gallon to cover everything—about $225 just for materials to stop seepage. Doing the work ourselves saved a significant amount; based on contractor estimates, DIY saved us anywhere from $1,000 to $3,000 compared with hiring pros to caulk and apply the Drylok.
Preparation was key. We cleared the room and removed fixtures that would interfere with a clean seal: an asymmetrical light fixture, a small metal tool organizer (which we freecycled), and old brackets and warped boards on the opposite wall.
We patched cracks with concrete filler and exterior caulk, then started the messy Drylok process. We learned Drylok comes in oil-based and latex-based formulas. The oil-based version is available in several colors (white, beige, blue, gray) and has much stronger fumes and warnings; the latex option comes only in white and has lower odor but is still stinky. We used the latex Drylok for the first coat and invested in high-grade respirators to block fumes entirely—well worth the $30 each for safety.
After the first coat, small tan spots began to appear through the white finish—mildew returning, even after we had sprayed the walls with a bleach solution and scrubbed them. The Drylok stopped external seepage, but mildew persisted. We decided to change approach for the second coat: instead of a white latex topcoat, we applied an oil-based beige Drylok. Painting over Drylok is not recommended, so a tinted oil-based coat serves as both sealant and final finish, hiding dirt and being more forgiving of imperfections than stark white.
A True Value expert suggested the oil-based version might provide a stronger barrier against moisture and mildew, particularly when combined with a dehumidifier. We planned the second coat for the next two evenings, prepared with respirators, and re-treated visible mildew with a bleach solution and a thorough scrub before recoating.
We chose beige over blue and gray because gray would emphasize the cinder-block look and blue felt too pastel. Beige is a neutral that pairs well with the white storage systems we plan to install for a lighter, more finished feel. The ceiling will also be beige for continuity, and the floor will receive a coat of chocolate-colored floor paint leftover from a previous project to add definition.
Have basement projects on your list? Dealt with mold, mildew, or flooding before? We’d love to hear about your experiences and tips as we continue the renovation. Fingers crossed we can even the score and claim a few points back from this stubborn basement.