I have a basement to dig tomorrow. It will be my first one that I have done. The lot slopes from back to front and to the right side. The back will be excavated approx 7 feet and reducing to about 3 feet at the front. Side to side will be 7 feet to very little. My question is about the sloping of the 7 foot area. It needs to be sloped a minimum of 3:4 when you excavate over 4 feet. It could also be benched? When you dig a basement would you start wide and gradually slope it until you reach grade or find grade and then slope it? I am a little bit stressed about it. I don't want to make extra work or look stupid. Thanks!
I am a foundation contractor and I don't understand what you are asking. -Is this a crawl space, or full basement? -What is your frost depth in B.C? -When you say "benched", are you talking about a "stepped footing", or do you mean the external grade upon completion? -Do you have plans with a section? -Can you talk to the mason?
It is a full basement house for a friend. Full walkout on 2 corners. What I am asking about is the 7 foot dirt height at the back of the excavation. It needs to be sloped back for safety or you could bench it to reduce chance of cave-in. I have seen videos of workers in excavations with straight walls that are over their heads when they are checking grade. I was looking for tips on how to slope efficiently. I was thinking it would be better to slope the excavation as I go deeper rather than go down to the grade and drag more material down as I sloped the wall.
okay, if you cannot dig it vertical because of the material or compliance regulations start with the outside edge of footer on the upper wall. add 3 foot of overdig for your foundation drain and to fit you're walk behind in. after that measure back 7 feet. on the upper bank that will be you're point ti begin digging. dig at a 1 to 1- every foot down = 1 foot horizontal. you will arrive with a laid back bank and still have room to work. most important dig it once and keep that back wall tight. any thing that is loose, pick out. you could also bench the dig. but i would lay it back and call it good. hope that helps.
In my limited experience, go slow, slower is faster and does a better job. You wont look foolish.
Here are a few pictures. We have run into sand. The best beach sand you could ask for. First picture is after scraping top soil. Second you can see the pickup with a good load of sand for his kid's sandbox. There is a ground level basement slab and then it comes up 6 feet to the top level. Third picture shows the sand. Monday will be concrete contractor,building inspector, engineer, geotech etc looking at the sand and what must be done. The whole top level is mostly sand. Any ideas what will need to be done? Do you have excavate it out all the way down or can you put a top level of good material on sand?