I'm working on waterproofing a section of my block wall foundation because I've noticed water seeping in. After taking care of surface issues, I need to dig a small trench next to my house (about 12 feet long). Because of the nearby trees and septic tank, it has to be hand-dug, which I expect will take around 5 to 6 days. This trench is quite deep—7 feet wide by 6 feet deep—with sloped walls. I'm a bit worried about leaving it open for that long. I heard that a good foundation shouldn't really rely on the soil to stay intact, but I have a shelter built over the trench to keep out rain. I've done my homework but just want to check if anyone has experience with this and how long it's safe to leave a trench open without causing damage.
2 Answers
Just a heads-up, anything deeper than 5 feet usually needs some kind of support to prevent it from collapsing. Have you thought about how you’ll waterproof it?
You can technically leave it open for a while, but the major risk is if water gets in, which could lead to a collapse. Just keep an eye on the trench to make sure nothing bad happens. As long as you monitor it, you should be okay for a few days.
I plan to repair the weeping tile and replace that section. I’ll clean and check the foundation, roll on some waterproofing, and then finish with a dimpled membrane.