[texasholdem]

I'm am considering a Arxx system of poured basement walls with styrofoam in and out. Looks like a good system. Any comments good or bad. Ordinarily I would hire a mason and use 12 block,waterproof and insulate inside. This poured wall system seems to have many advantages. Comments? Trying to be my own general contractor. I have an architect and will hire Subs. Comments

 

[concretemasonry]

What you are describing is probably an ICF (Insulated Concrete Form) system that uses a 6"(usually) concrete wall inside of the pretty and impressive forms that are left in place after the concrete is poured. There are few basic problems with type of system:

1. These systems are relatively new and many contractors are not too good at bracing the forms, which will move as the concrete is placed. It is essential that the concrete is placed in lifts progresing around the basement, followed by several more lifts to allow some natural consolidation over a period of time. Usually a pump is used by better contractors to allow proper placement instead of dumping a lot of concrete in one place and hoping there is enough excessive water that lowers the quality of the concrete. ICF systems are impossible to inspect economically. The alternate is to have an on-site inspector and want to have a non-destructive equipment to measure the thickness and density of the concrete.

1. Since the walls are never seen, the common concrete placement erros or practices are never seen or corrected. Even the old formed systems allowed an opportunity to see the defects and correct them instead of hide them.

2. In either foam forms or wood/alumiunun forms it is absolutely essential that proper vibration (a vibrator and not just a stick) is used to consolidate the concrete. The historical critical areas where problems are seen are near corners, under/around windows or any other openings. Another concern is the squareness of the foundation that may have shifted during pouring/placement/curing where the framing contractors will have to "make things work".

A concrete block basement can be the same or greater strength as either a poured or ICF foundation of the same thickness. An advantage of a block basement is the it does not rely so much on the placement methods/procedure since " what you see is what you get" and the hidden part is the same steel reinforcement as other systems, but the grouting is much more reliable since it is necessary that the grout must be much wetter than concrete to perform well, which is a blessing when it comes to placement.

In your area, do you need the extra cost of the insulation in a basement where the minimum soil termerature may be much higher than the outside temperature?

Dick

 

[yesitsconcrete]

usually agree w/dick but here's our take,,, we used external vibration rather'n the usual dipsticks to avoid segregation,,, yes, proper bracing's extremely important at mid & top of wall,,, there walls will move,,, pump into the cells 3 or 4 rows at a time & keep moving ! ! !,,, works better if you neck the hose down to 3" from the conc pump boom,,, alum angle extrusion nail'd to the perimeter helps keep icf's in place.

here's 1 area where we part,,, i don't believe block's ever as strong as conc UNLESS its grout fill'd,,, even then, its impossible to place backfill in compact'd lifts as the cmu's have little lateral strength.

imn-s-hfo, :laughing: the advantages of icf FAR outweigh ANY other form of foundation &/or method/materials,,, matter of fact, i don't understand why the whole house isn't icf up to the gable,,, ours will be :thumbup:

 

[jomama45]

I would agree mostly with Dick on this one. I believe a typical 12" CMU foundation if stronger than a typical 6" ICF wall. Today's block basements are a far superior than the block of yesteryear. 9 foot walls require grouted pilasters with #5 minimum rebar (we use #7 or #8's) on 40" centers. In my observations, this design works better than filling the entire wall with concrete, unless it's an Ivany wall system. Hollow block are drier than poured, allow a secondary cavity to control a leak, & are far less prone to shrinkage cracks common in block walls poured full of concrete.

I have nothing against ICF's, especially if it contained a 8" poured wall. There seem to be a few more things to point out though. The entire interior of the basement must be finished (to cover foam) with drywall, your limited to where you can anchor, & usually, just the concrete, re-enforcing steel, & ICF forms cost more than an installed block or poured basement.

 

[yesitsconcrete]

big deal - you're both from the same area :laughing: always watchin' each other's back, too ! ! !

yomama's partially right imo,,, compressive strength is good on today's block but, absent latex acrylic in the mortar, there'll still be 100's of pin holes in the jnts susceptible to soil acid attack as is the lime in the block's cement itself,,, have yet to see any efflorescence in icf's,,, icf const is more expensive but the addl cost, according to what we blt, was amortized thru lower utility costs w/i 18mos.

you would need different anchors if you want to mount shelving suspend'd from a wall but most i see're blt on stiff legs,,, imo, if you think utility costs'll be head'd down, use conc,,, on the cheap initial price, block - MY house, icf w/o a doubt - footer to gable! ! ! :thumbup:

 

[jomama45]

YES, your OK for a guy who's lost his mind.:laughing::laughing::laughing:

I have no doubt that an ICF foundation YOU put together would ever be inferior. The point I'm trying to make is NO foudation is neccessarily a DIY job. The foam forms may be appealing, but they demand more respect & attention than any other cast in place foundation. I'm not quite sure I'm sold on the advantages of the extra R-values below grade either. Once you get 4 feet below grade in my region, ground temps are generally 55 degrees all year. That's alot of money to spend to insulate against 10-15 degrees. IMO, you can spend that money above in ground insulating & get better overall results. I have no issues with ICF's above grade, & can see many advantages. I just cant see spending that kind of money & stopping at the first floor mud sill.

 

[wildcat]

The quality of ICFs are completely dependent on the contractor doing the work, as already stated. So, you'd really want to do some research about who you select for the ICFs. I also agree with idea of why stop the ICF walls at grade?

CMU foundation walls are great and so is the traditional poured wall (especially with the use of proper add mixtures to get self consolidating concrete).

If you're are just looking to do something a little out of the norm, I would look at precast foundation panels. Or even doing complete tilt-up construction for the foundation and above grade walls (may not be economical, depending on the scale of the project)

Structurally they are all completely viable options. As with any foundation system I would recommend spending money on an excellent drainage system for your foundation, especially with having a basement.