We're in the middle of a major renovation, turning our unfinished basement into an Accessory Dwelling Unit (ADU). The foundation was built in the early 2000s, and we've only noticed a minor water spot occasionally when a lot of ice or snow melts quickly. However, since we live in the Pacific Northwest where it's often wet, we want to avoid any potential water damage after finishing the basement. We're currently considering our drainage options and trying to figure out whether to go with a French drain, a foundation drain, or interior drainage with a sump pump. We've been getting mixed opinions from contractors and would love some unbiased advice!
3 Answers
You might want to check out ASIRI Designs; they've got great resources on basement waterproofing! Their website and YouTube channel have tons of info that could help guide your decisions.
Just a heads up: even if you only see that one wet spot, moisture could still be moving through your foundation. You could try taping a piece of plastic to the interior wall; if it darkens, moisture is coming in. Then you'd definitely want to add a waterproof layer on the inside and make sure water is managed from the outside too. It's more than just fixing the symptoms—you have to address the source! If you have only 4 inches of block foundation, maybe consider sealing the outside as well. It's worth spending some time on this before finishing everything up!
You know, I've worked with a lot of contractors, and it’s often the case that they specialize in specific areas. The one that told you not to dig outside? That sounds like BS to me. The focus should be on preventing water from entering rather than just dealing with what gets in. An exterior French drain at the footer can be really effective, especially combined with sealing the foundation. Don't forget to manage your gutters and downspouts too!
Absolutely agree! Diverting downspouts far away from your foundation is key. And if that's sorted out, a French drain and proper grading are crucial for keeping your basement dry.
Thanks for the tip! I’ll definitely check them out.