Replies

1. 
   slykarma | Oct 13, 2004 06:34am | #1

   Please, have it engineered and inspected to code standard. Better in the long run for you and subsequent purchasers. Modifying foundation should not be trifled with or built by rule of thumb.

   Wally

   Lignum est bonum.
1. 
   rickchem | Oct 13, 2004 08:01pm | #3

   I'll getting a permit, having it inspected, and it will be up to code.  However, I want to make sure it is done right, not just up to code.   I'm interested in the procedure and details.  For example, any advantages either way for excavate and pour, then cut wall, or excavate, cut, then pour?  And tie in details for the additonal concrete, and ideas on drains- whether to ties into interior sump, drywell, or both.  Just wanted to see if people had any neat ideas.

1. 
   BillHartmann | Oct 13, 2004 08:44pm | #5

   You said that you only have wheelbarrow access. How wide is that.

   You can get mini-track excavators that are less than 4ft wide.

   And the I think that the compact, walkbehind, skid loaders are even narrowers. While I don't thing that the backhoe on those are big enough to do the full job they would still help. And you have the bucket for moving out the dirt and in gravel.

   And a concrete pump can put used when it is time to pour the stairs.

   You might also want to look at the possibility of workign with a neighbor and going through there yard if that is a possibility.

   And in the most difficult cases you can get a crane to lift in equipment and even the precast stair assembles.

2. 
   SethArgon | Oct 13, 2004 06:44am | #2

   I dont know where you live but it isn't just a matter of removing the dirt, cutting the doorway, and putting steps down to the basement. You will have to dig down below frost level where the door is and to the left and right as far as frost reaches bellow grade in your area and poor new footings

1. 
   rickchem | Oct 13, 2004 08:05pm | #4

   Well, I WAS just going to dig down and construct steps and retaining walls out of pine 2x4's :-) haha

   I know I require footers, permits, etc.  I know cutting into a foundation wall is a big project.  I'm more interested in details people have found necessary/helpful in the process, such as draining techniques etc.

1. 
   SethArgon | Oct 13, 2004 09:23pm | #6

   I would find out from an engineer if your basement wall could support itself if you undermined the footings in the effected area. If it can then I would take the house load off with jacks then dig the area out and undermine the footings until I got bellow frost line. Put some rebar in and fill the void with concrete. Now you have a frost footing Before taking the load off the jacks have the doorway cut. I would have the wall cut all the way up to the sill and frame in a new header(as opposed to leaving a concrete header) because you don't know what kind of reinforcement is in the wall. Once header and doorway is framed in(and concrete cured)you can let the load off the jacks. Now form up retaining walls and poor them, the stairs and the landing. Don't forget to put the drain in. I will try and attach some quick drawings I did. Those mini excavators work great & pumping is the only way to go either a line pump or boom pump. Line pump would save the $.

1. 
   slykarma | Oct 14, 2004 07:08am | #7

   Unless this is a mighty big wall and/or opening, a pump is going to be real expensive. Think about it, there will be:

   retaining wall ftgs plus extra concretre to beef up basement ftg.: 1.5 cu yd./1.2 m3

   retaining walls: 4.2 cu yd./3.4 m3

   stairs/landings: 1.7 cu. yd./1.4 m3

   total: 6.0 m3 (one concrete truck load)

   I had to assume a bunch of dimensions (like stair and landings 3' wide, footings 32" x 8", 10 risers @ ~7" and so these could be very different plus or minus. The only one I might consider for a pump would be the wall pour, but it would still be a lot of money. Around here it is $200/hr with 2 hr minimum. The other pours, forget it. Wheel it in. Check out the mini-crete guys, maybe they can get closer than a regular full size truck. Or consider renting a mixer and mixing on site if you can get the aggregate in close enough.

   The company I work for is the biggest commercial GC in the region and they buy so much concrete that we get hot rates on concrete and pumps, but management would still kick my arse if I were to order a pump for a 1.2 metre footing pour. And if it were columns or other vertical work I had better have a pretty damn good reason why they couldn't be poured with something else to make the pump viable.

   Aside from all that, I would excavate it, lay everything out and then cut the door opening so that access to inside and outside of basement wall would be easier, especially when undermining ftg and forming both sides for underpinning. 

   On principle I would avoid draining exterior runoff into interior of building. Always supposed to direct water away from strucutres, not toward them. Small dry well during excavation or tie into ftg drain if available. Also use the opportunity to connect roof drains if present setup is at all sketchy. Finding and tying into storm sewer would be unecessary unless the new stairwell is situated so that local terrain directs a lot of runoff in that direction. 

   Finally, do take the time to drill and epoxy rebar into existing ftg and walls. Time and cost are negligible compared to walls slowly being pushed out of plumb by hydraulic soil pressure.

   Wally

   Lignum est bonum.