Clogged gutters and downspouts cannot properly drain rainwater from your roofline and away from your home, but how much of an impact does cleaning them out really make in terms of basement waterproofing?
Often, when doing home energy performance work, we first air seal houses and then add ventilation. This may seem counter-intuitive and some might ask, why would I decrease the ventilation of my home and then increase it? The answer, in one word, is control.
Sealing off your crawl space vents is a step in the right direction. But if that's all you do, you could end up making the problem worse. It's also important to install a drainage system and sump pump and control humidity with a dehumidifier.