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harpo103
building new foundation

Hi. I want to put an addition onto the house and one person told me to build the basement foundation out of block, but, I thought that poured concrete would be a better idea. You know.........use the blue styrofoam forms with the plastic ties and just pour the mix and leave it in place. Is there a major cost differential? The poured stuff seems more watertight to me!

Ron remodeler
Re: building new foundation

Blocks are inexpensive and can be "Parged" with a coat of plastering like stucco that is made for a technique called stack and bonding. It has waterproofing properties and is spread like plaster over the block surface to insure strength and water proofing.
I believe Lowes carries the product as do other places but I have never seen it in HDepot locally. It has been around for years and works well.

The expense of the styro forms out weighs their valubility to me when a regular form job for concrete is fine. I do not like the fact the styrofoam attracts many insects to live along your foundation and gain access to your walls, especially termites.

I have built both poured concrete foundations and block and would recommend block for a room adition and a man who wants to do his own thing. Be sure to use the sturdy wall wire every few courses to insure strength and us 12 inch block where necessary.
I ususally solid fill the top courses and solid fill every 8' to insure structural strength and lock out the insects with the top cores filled solid.

harpo103
Re: building new foundation

Thanks.
I'm not building this myself. I want to get a foundation guy to put it in, I just wanted to know the pros & cons of each system. I'll do the finish work myself. Drywall, insulation, floor, trim etc. It's better to go into this with knowledge aforethought.

calcats
Re: building new foundation

You might also ask your contractor to price Ivany concrete block filled with concrete. Put 3/4" vertical reinforcement rods in the webs every 3' and reinforcement wire horizontally every 3rd course. This makes a very strong wall for a price a little less than all concrete (you save the labor and material for all the forms) and a little more expensive than just block. Just some food for thought.

Calcats ;)

harpo103
Re: building new foundation

The styrofoam forms seem like a good idea, in theory anyway. I figured if you can put forms in the hole and then just leave them there to be used for insulation..........so much the better. But, it appears that they may be troublesome as far as bugs go. I've seen it used on TOH......but what do I know?????????????????
I want the new basement to be dry as a bone. Or at least as dry as I can get it!!!!!!!!!! Thanks.

Timothy Miller
Re: building new foundation

Howdy the foam block is much stronger then block walls. Much less likley to crack. The foam reinforeced cement wall with about R50 so you do not have to insullate interior. Some foam block now made with anti insect chemiclas.
One draw back is cost. The foam block is pricy.... Might have them bid reinforced cement and consider adding exterior 4 by 8' 2" foam yourself lots less $$$.

canuk
Re: building new foundation
harpo103 wrote:

The styrofoam forms seem like a good idea, in theory anyway. I figured if you can put forms in the hole and then just leave them there to be used for insulation..........so much the better. But, it appears that they may be troublesome as far as bugs go. I've seen it used on TOH......but what do I know?????????????????
I want the new basement to be dry as a bone. Or at least as dry as I can get it!!!!!!!!!! Thanks.

jkirk nailed it.

Another note ... many building codes will recognize using waterproofing below grade ..... whether it's peel and stick or applied rubberized ( sprayed or applied by hand ) along with an air gap membrane along with parge coat on above grade as sufficent insect proofing ICF's.

Regardless which system you choose ...... block , concrete, or ICF concrete .......the above method of waterproofing ( not damproofing ) the exterior side of the foundation is key to a long lasting dry basement .... along with proper drainage around the footings.

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