Basement Types

[RobS]

I rented my forms for our den addition from that place. Ersco, or something like that right? That was kind of fun. Only four foot walls and I was supposed to borrow forms from a contractor buddy. At the last minute he ended up needing all his forms for a big commercial job and I already had a hole in the ground with a footer. Ersco was most helpful and very reasonable. Good workout moving those things around though, I can't imagine lugging the eight footers all day long /w3tcompact/icons/smile.gif

 

[RonL]

MossRoad

"Some contractors recommend that you pour the basement walls in the fall and let it sit all winter to cure".
The problem with this is you leave yourself open to frost heaving. If the excavation is open you must remember that the frost line is now below the footing level. I'm of the opinion that foundations should be back filled and closed in before winter. I've seen foundations damaged by frost heaving. Also, some people excavate in the fall to let the site "settle". If you form and pour before the ice lens has melted there will be settling. Again, the area where the footing goes should be thoroughly compacted before pouring..
Site preparation is an important part of a sound foundation. If the soil is not capable of supporting the weight that is put on it , it WILL settle. Water can also undermine the most solid foundation.
" The fool builds his house upon the sand. The wise man builds his house upon the rock".

RonL

 

[RayDiers]

I used wood foundation wood to build my basement. That was 15 years ago. I have a nice dry basement yet today. I was lazy and had someone pour a concrete footing so leveling was not a big hassel. One reason for wood was that I could do it myself just like the rest of the house.

Ray

 

[GlueGuy]

To fill in a couple of blanks here, it turns out that "gunite" was an early name given to what is now referred to as "shotcrete". It has come a long way since those early days. For the old-style gunite, there were limited applications because the process did not produce a very strong structure, and tended to have a lot of entrapped air.

These days, they have learned a lot about the chemical makeup, and other things to make the resulting material as strong as, or stronger than poured concrete. Here are a couple of links that I've found:

First there is the <A target="_blank" HREF=http://www.concretehomes.com>Portland Cement Association's Concrete Homes Website</A>

Second, they also have a little expose' on <A target="_blank" HREF=http://www.concretehomes.com/buildingsystems/shotcrete/sys-shot.htm>Shotcrete</A>

Amazing stuff. Looks like a good way to go.

 

[MossRoad]

They poured my grandmother's foundation in the fall, waterproofed it and insulated the outside. They back filled it and left for the winter. I agree with the comment about frost heave as the wall was sitting on the footer, and the footer was only a foot thick. They back filled up to the footer, so the bottom of the foundation was only 12 inches below the surface. The recommendation around here is 26", I believe. The basement was 10' deep with 12" walls and lots of rebar. The walls never cracked. Anyway, they built the house in the spring and then poured the basement floor after the 1st floor deck was completed. It worked out well. Except that there were a half dozen dead rabbits in the basement in the spring. Aparently they were running through the yard and hopped over that short little wall and.../w3tcompact/icons/shocked.gif

 

[gerard]

<font color=blue>I have recently read a report that recommends that after a slab is poured and begins to set a perimiter
dam is set up and the surface is flooded. This allows the slab to cure slowly without inducing internal stress.</font color=blue>
Concrete takes about 30 days to acheive about 90% strength. The slower the cure the stronger the concrete. Concrete is an exothermic chemical reaction and the water helps keep it cool which slows the reaction, hence a stronger cure. Pouring in hot weather is about the worst you can do unless you keep it watered and cool which is why you see sprinklers/burlap etc on concrete. The cracks are from the concrete curing too quickly. The voids you see in poured walls are from not using a vibrator properly when pouring. (Takes time/money to do it right).

I know some concrete people who put polyethylene under all concrete slabs and when they do their own homes they flood the pour with water for a week. (These are the guys who poured the floors for the Anheuser Bush plant in Syracuse NY, 12 inches thick, smooth as glass and I never did see any cracks!) I put the poly under all my slabs in my last home and didn't get any cracks anywhere. (Prevents the soil from leaching water out of the mix as it cures). Cheap and easy to do but most contractors won't do it unless you require it.

 

[MossRoad]

The plastic also acts as a moisture barrier later on. It is code in some places.

 

[RonL]

MossRoad

The plastic may also act as a radon gas shield.

RonL

 

[buckeye]

Well, I thank everyone for their posts. It looks like we are going to go poured wall. I am meeting with contractors this Friday and Saturday to get quotes. I'll let the group know how it goes.

 

[RPM]

You should also consider pre-cast concrete. Quite a few houses in my area are now going in with this method. They look like an 8x4 pre-cast concrete form that is insulated at the factory. You pour the footer and then just bolt as many of these things together as you need.

I prefer poured concrete myself - but you may want to look into these things. Sort of a half way house between block and poured concrete.

Patrick