Basement Types

RobS · Jan 15, 2002

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 · Jan 15, 2002

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 · Jan 15, 2002

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 · Jan 15, 2002

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 · Jan 16, 2002

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 · Jan 16, 2002

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.
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 · Jan 16, 2002

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

RonL · Jan 16, 2002

MossRoad

The plastic may also act as a radon gas shield.

RonL

buckeye · Jan 16, 2002

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 · Jan 17, 2002

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

GlueGuy · Jan 17, 2002

consider pre-cast concrete

The portland cement association's web site talked extensively about this. They call it "ICF", or Insulated Concrete Forms. Consists of a thick sheet of foam insualtion, with a wire mesh embedded on each side, plus concrete shot over the wire mesh on both sides. The resulting structure is "extremely strong", plus has a large thermal mass on the inside. The materials used should last 100 years, if not longer.

This is a sort of "composite construction" that has become popular in the aircraft industry.

kiphorn · Jan 17, 2002

I'm building a new house in the spring and plan to use precast walls. Around here precast walls are becoming very popular. I visited the factory and watched them pour the walls. Its a pretty slick operation. The concrete sets up to 5,000 psi (I think). The high psi concrete and the foundation drainage are supposed to eliminate wet basements. They tell me they can set an average basement in about four hours.

<A target="_blank" HREF=http://www.superiorwalls.com>Superior Walls</A>

Kip

cowboydoc · Jan 18, 2002

Just make sure that you have a VERY knowledgable person that can do the SIP or precast. I have seen some guys that didn't exactly know what they were doing and blew out the forms from this type of wall. The one contractor even came back and tryed to charge for the blow-out to my friend that was having the wall done. But this is the same guy that put up the trusses and didn't have them anchored good enough and they all blew over. Again charged my friend for that too.

webbmeister · Jan 18, 2002

All these posts, and not a word about Permanent Wood Foundations. Anybody heard of 'em? Good experiences? Bad?

beenthere · Jan 18, 2002

Just recently I posted information about PWF. Search of PWF will give valuable information, and these foundations have been doing well since their beginning in the early 60's. Not a lifetime yet, but I think there are advantages worth looking into.
<A target="_blank" HREF=http://www.tractorbynet.com/cgi-bin/compact/showthreaded.pl?Cat=&Board=rural&Number=99241&Search=true&Forum=All_Forums&Words=Permanent%20Wood%20Foundations&Match=Entire%20Phrase&Searchpage=0&Limit=50&Old=allposts&Main=99232>http://www.tractorbynet.com/cgi-bin/compact/showthreaded.pl?Cat=&Board=rural&Number=99241&Search=true&Forum=All_Forums&Words=Permanent%20Wood%20Foundations&Match=Entire%20Phrase&Searchpage=0&Limit=50&Old=allposts&Main=99232</A>
This is the thread (search on Permanent Wood Foundation) I posted.

webbmeister · Jan 18, 2002

Maybe it's age (I hope not, I'm only 45) or too much Diet Coke, but I read every post in that thread just last week. I did not remember until your wrote this reply. Thanks for the reminder!Jim

GlueGuy · Jan 19, 2002

One of our neighbors built a house with PWF around 1973. They had a fire about 5 years ago, and had to restore part of the house. They mainly had smoke damage, but the restoration allowed himto inspect the wood that had been out of site for over 20 years. He said it looked as good as the day he put it in.

RPM · Jan 20, 2002

Re: Superior Walls

Those were the walls I was thinking of - thanks for posting the link! (Lancaster County where the business is run is one county over from me).

Patrick

Anonymous Poster · Jan 21, 2002

I could not agree more with this statement. Real reason builders go with poured wall is once forms are up concrete contractor wants to get it pourd and his forms freed up so he can use them on his next job. Mason can tie up several jobs in various stages of completion and have little incentive to finish up other than wanting to be paid. Concrete tends to be more expensive but both materials will do a good job if properly installed.

PS: I am a bricklayer by trade and sometimes we are our own worst enemy.

patrickg · Jan 22, 2002

Buckeye,

Like the GlueGuy, I'm sneaking up on an earth sheltered design for my new home, although I am considering a hybrid design, i.e. some earth sheltered spaces with 3-5 feet of dirt cover over elipsoidal domed "cathedral" ceilings and some conventional appearing spaces that are not conventional stud walls but instead are steel reinforced concrete using ICFs (Insulating Concrete Forms). I have looked into ICFs and followed their increasing popularity for years. I strongly recommend a poured basement using ICFs. Many advantages. You can easily do it yourself as the ICFs are light and easily cut. They are made of EPS (Expanded PolyStyrene).
Like the GlueGuy said, you can get someone to do the hard part, foundation/footer, pouring the floor if you aren't into large cement finishing jobs (I have a different take on that, see below...) Placing the ICFs is easy and suitable for DIY. Placing the rebar is easy and with bar ties and the twisting tools there isn't anything requireing beef. An angle grinder with a cut off blade will cut rebar if you don't happen to have a handheld electric/hydraulic rebar shear as I luckily do. Given the volume of concrete you will use, you should get a good deal on on a concrete pump for filling the ICFs. Do use a vibrator to avoid voids but don't get too agressive as a blowout is possible.
I've done concrete with conventional forms. I've done concrete by dry stacking blocks and 100% filling them with concrete but with luck I won't start any large projects via either method ever again. They are labor intensive. In the last couple weeks I have stacked nearly 10 tons of 40 pound blocks complaining the whole time that I was too stupid to get custom ICFs for the wall thickness I wanted (miminum of a foot thick). Half way through I noticed an offer by a ICF maker to provide custom widths.
Anyway, whether it is purchased labor or yours, there is a lot less of it with ICFs and you don't have to pull the forms as they stay behind as insulation. This is a GOOD system. There are even companion ceiling methods for pouring ceilings. GRRRRRRRRRR!!!!!!!! Tomorrow I get to start forming up to pour a foot thick ceiling. I will have a virtual railroad trestle of braced and cross braced wood to hold it up.

One last thought... Consider poured walls using ICFs.

Patrick