How Much Space Needed to Pour a Foundation & Frame Walls?

[gbaker]

I think my framing question is solved by using cement blocks! Sorry for the errant post.

 

[nealtw]

I think my framing question is solved by using cement blocks! Sorry for the errant post.

You still need room to lay the footing, usually the hole for a new house has 4 to 5 ft all the way around the outside.

 

[slownsteady]

It wouldn't be errant, even if you solved it yourself. There are others here who may have the same or similar question.

 

[gbaker]

Thanks for the encouragement! As I often say to others, the only stupid question is the one you don't ask...

I've been reading books, watching videos, prowling around forums trying to learn how to build a house before I hire someone to actually build the house. Trust issues? Maybe, but I also really want to understand how the whole thing works. I'd also like to do as much of the labor as I can myself, not just to save money (since whatever I do will probably end up costing more) but to have a project I can take pride in.

I definitely want to do my own designing, and knowing how the structure works -- and what is not just possible, but practical -- is critical to do a good job there.

I was hung up on how you frame the walls from the inside out and then demo the old wall on the other side, and figured I'd just step back enough room to build and then connect the two later (and enjoy the courtyard byproduct), but if I just built up against the face with cement block, that new wall could carry the second story and there's no need for immediate finishing on the other side, right? That would also save me a little valuable back yard space.

 

[gbaker]

You still need room to lay the footing, usually the hole for a new house has 4 to 5 ft all the way around the outside.

I watched a video of a large addition where the excavation was flush with the existing foundation along the back wall, so if you don't mind educating me, why does the footing need to be wider than the perimeter. (I actually though it WAS the perimeter.)

Or is it just that the hole needs to be wider than the footing to allow for the framing of the footers and foundation walls? That would make sense, and it would probably also answer the initial question, which is how much room does a man need to work?

 

[nealtw]

Footings are allways wider than the wall, to give it a bigger footprint on the ground to spread the load. The width is dictated by the soil condition, the city or maybe an engineer. Some times if there is a heavy pointload above a wider footing for that might be needed. Beleive me 4 ft out side of the house measurements is the min.. I don't know where you are but the bottom of the footing has to below the frost level for your area. So for a walk out basement the footing can be as much as 4 ft below the floor level.

 

[gbaker]

That might answer my question about how a slab foundation gets reinforced, too. I assumed that the foundation walls had to rest on top of the footers and that the walls had to rest on top of the foundation, but it sounds like you're saying that a footer that is wider than the walls above it can spread more of the load outward, independent on where the wall lies in relation to that footer. Is that right?

Frostline is 12" I think, but I haven't seen anyone reference 48" wide footers. Most things I've read talk about a 16" footer. I'm just trying to carry two stories with cement fiber siding and a 4:12 metal roof.

 

[nealtw]

All our plans a drawn with 18" footing with the wall centered to that but we also have to have a geo tech engingeer out, he checks soil type and condition. Sometimes they wants more dirt removed and replaced with compact gravel and he decides how big the footings are and how much re-inforcing steel is put in it.

 

[gbaker]

Thanks, Nealtw. I'm just trying to eliminate too many surprises and start out with a workable plan before I spend half my budget learning that what I want to do can't be done.

 

[nealtw]

Mostly you can plan every detail and cost, but the foundation sometimes is the great unknown until you dig the hole.

 

[mudmixer]

nealtw -

If the wall below grade is concrete block, the excavation on the outside does not have to be that wide unless drain tile need to be installed.

Block can be laid from the inside of the wall (and still tooled joints). It is commonly referred to as "over the wall" construction. - This method can radically reduce the problems, especially when a wider excavation can accumulate much more uncontrolled water after an overnight rain.

Dick

 

[nealtw]

nealtw -

If the wall below grade is concrete block, the excavation on the outside does not have to be that wide unless drain tile need to be installed.

Block can be laid from the inside of the wall (and still tooled joints). It is commonly referred to as "over the wall" construction. - This method can radically reduce the problems, especially when a wider excavation can accumulate much more uncontrolled water after an overnight rain.

Dick

The depth of the hole was not discussed, as there is no way to shore up the side of the hole, I'm not getting down to nail a footing frame together against a 6 or 8 ft dirt wall with a loose dirt pile beyond that.
We have had a bank come down overnight and take out twenty ft of forms and that was with a 5 ft walkway. Glad I didn't have people in there when it happened.

 

[gbaker]

Unfortunately I have no idea what's underneath the original house, short of concrete slab. I doubt it's reinforced since the construction seems pretty shoddy to me (frame with shingle and not an ounce of insulation between) and a third of the house is really a poorly enclosed carport (that's the part that is definitely coming down).

Drainage will be necessary, especially since the lots on either side have been regraded at least six inches above mine and flooding was already an issue.

I've decided not to bother trying to build a partial second story over the existing house because I suspect the needed reinforcement would cost more than demolition, but I will see if a higher pitched roof with floating dormers is possible and use that to tie in aesthetically with the two-story addition. If that's not possible, I'll just tear the whole thing down, lose more yard with a bigger addition, and build an enclosed entry porch on the existing foundation, since that has to be retained (at least in part) for the rehab loan.

There are so many interlocking pieces of this puzzle that it's daunting to even get to the contractor phase, but your input has really helped. Thanks again!

 

[gbaker]

The depth of the hole was not discussed, as there is no way to shore up the side of the hole, I'm not getting down to nail a footing frame together against a 6 or 8 ft dirt wall with a loose dirt pile beyond that.
We have had a bank come down overnight and take out twenty ft of forms and that was with a 5 ft walkway. Glad I didn't have people in there when it happened.

I can't imagine a worse scenario than having workers buried alive! I realize that some things are "possible" that really aren't practical, and I think my initial question was in response to that. I don't expect workers to work under difficult (never mind unsafe) conditions, but I realize, too, that I can't necessarily provide the optimal environment. Finding the right balance is what I'm striving for.

 

[nealtw]

I gave you my opinion on what I want ,it is also industry standard here and the regs for workers safety.
Ask your permit dept., they will either tell you or send you to someone who will know what is needed, for your area and the depth you are digging.

 

[bud16415]

As a kid the basement hole was about 18” on a side bigger than the basement and blocks were laid from the inside. In sandy soil they went bigger because they had to. The risk people took to save a little digging was a carry over from hand dug basements I think. With todays machines and safety code get as much dirt out of there as you can and make the job easy IMO. We had a guy build a log home up the street and he was trying to save trees close to the house. He had his whole basement pre-cast and trucked in walls were joined at the corners. Even the basement stairs were cast in. no footers they came attached to the walls.