Basement Benching

[AncientHouse]

Hi Everyone,

Anyone know where to find step by step on Basement benching? Or has anyone done it themselves? I know if you dig down 2 feet you have to have a bench of 2 ft on each wall or 1 to 1. What I'm interested in is the process of putting the 1st bench. Do you dig near the wall 1st and put in the forms and then pour cement, wait for it to dry and then go on to the next wall or the rest of the digging? It's a stone house and the basement is currently at 5'3" we are about to have a company put in an interior drainage system but we don't want to lose any height or have to lift all the appliances (furance, water heater and water system). We'd rather get more head room if possible. The cost we received for benching was so outragious that we want to see if there is a diy. We already had the advice of an engineer which is how we came up with benching instead of underpinning. We don't want to disturb the soil under the 2 feet of the stone walls so we thought benching would be the way to go.

Anyone have info?

Thanks.

[AncientHouse]

I guess this is a tough one. We are having an internal drain system put in after we figure out if we can add some hieght so we at least don't lose any hieght. I found some info on the internet. I'm just worried about bracing while removing soil.

[Bird]

At least it's a tough question for us southerners whose homes are on slab foundations so we have little experience with basements.

[AncientHouse]

So that explains it.

[jimbrown]

Heck I thought you were building a sauna or something

[AncientHouse]

Okay, update on info. Between searching the internet and reading all thread in your new house building posts, you can probably give me some advice with more info. Because my house was built in 1861, there are no footings, the stone sits straight on the ground. The stone only goes 4" below the existing basement floor. I don't want to disturb the earth for underpinning so I heard about benching. The new info I have is that you can have the dirt go on a 45 degree angle from the wall for about 2 feet towards the lower portion of the basement that you are digging. Then you would create wood forms to create a box or ledge with concrete to enclose the dirt at that angle and keep it from moving. This would create the ledge or bench going 2 ft down and out from the walls to reinforce the walls so your house doesn't cave in when you dig the basement down for some height. Would I use rebar to reinforce the concrete and has anyone heard of this type of thing? Benching is less expensive than underpinning and I don't mind losing the 2ft of space per wall.

[AncientHouse]

RCC WATERPROOFING, THE WATER STOPS HERE
Here is a picture gallery showing benching but of course it isn't a how to so I had to find out about the 45 degree earth in another search of the internet.

[AncientHouse]

Here's another question that's related. If I don't want to worry about the water level of the ground water and my walled only go down 4" to the soil they sit on, can I dig to the 4" without any structural danger?
When the drainage system goes in, it will need 6" including the cement floor which will put the floor to 6" from the bottom of the walls.

So can I dig down to the full 4" without bracing the walls while they put in the drainage system?