construction question-Footing, basement, etc

salzo

I am planning on adding an addition to my house. Our house is knid of built into a hill, which makes the back of the house below grade, while the front of the house, the distance from the first floor to the ground is 3 feet. We have a patio with steps so that you can get to the front door from the ground. What I originally planned, was removing the patio, placing the addition on the side, pouring a congrete floor, so that there would be a 3' crawl space(distance between ground and 1st floor level). Now what I am thinking is perhaps digging down 4-4 1/2 feet, and having a basement(4 feet underground, + 3 feet of area above ground).
I have been in unfinished basement with concrete walls, and I always assumed those congrete walls were the footer of the house. So what I am thinking is, if I put in footers that are 4 feet deep, the only thing necessary to have a basement would be to excavate in between the footer walls-or am I in left field? Is a basement wall DIFFERENT than the footer of a house?

"Waiting tables is what you know, making cheese is what I know-lets stick with what we know!"
-Jimmy the cheese man

reb8600

The footer is actually a slab under the wall. It is usually 12"-18" wide and about 10" thick. Then you pour the wall on top of it. The excavation should all be done before you pour any walls.

Guncontrol-The ability to hit what your aiming at.

jsergovic

About one block (8") below the bottom block of your basement wall is the true "footer", if your area (Bucks County, PA ,U$$$$A)

This footer is about 16" to 18" wide, and 6" deep, straight concrete with maybe some re-bar in it. The the masons started stacking 8x8x16 block on up until it was at the desired height.

If you want to make a matching addition basement, you would knock out the patio, dig down to the footer, and trench out a new footer in the footprint of the addition.
All this might take a backhoe two days ($1500, removal included).

Permits and inspections add to the project.

Waterproofing agents have improved in the last few decades. The outside block wall underground should be well-coated and even insulated with rigid foam prior to back-fill. Note: a "header" will be required when constructing a doorway between the two basements.

I'm just guessing on all of this. I'm a plumber, not a mason or structural/stationary engineer. But I've seen plenty of buildings built.

Jim the timpanist/plumber from California

nord

For heaven's sake Salzo, give me a call before you go and do something stupid. I guarantee that the trip to Corning will be worth your while.

At least find out what you don't know.



Nord

salzo

quote:Originally posted by nord
At least find out what you don't know.



Nord


From what I am gathering from Jsergovic and reb 8600s post, there is a lot I dont know.
Can anyone suggest a book dealing with this topic, or a general building book.

"Waiting tables is what you know, making cheese is what I know-lets stick with what we know!"
-Jimmy the cheese man

bigdaddyjunior

In your local library in the reference section will be a book of state building codes, usually blue in color. Look under residential foundations for the specs. Here and in a lot of places to build adjacent to an existing foundation you must make two seperate pours. The first starts about three feet out from the existing, depending on how deep the original footer is, and is dug at an angle toward the old one to give it lateral support when you excavate near the building. After the first pour cures to strength you can dig out the dirt between the old foundation and the angled pour and lay your new footer butted up next to the old one. A second way is to just pour a footer four feet out from the old one and cantalever off of it to the existing structure. It uses up a lot more materials this way, thus costs a lot more to build your addition.

Big Daddy my heros have always been cowboys,they still are it seems