foundation recommendations

[mobilesport]

Here's my final floor plan , I'm going to ask the building inspector what he recommomends/requires for a foundation but hav'nt talk to him yet ,
Can anybody recommend a foundation for this? It will be in Iowa were it gets pretty cold sometimes. i want to build on top of a block wall but dont know what would go under the blocks , i was thinking of 4 foot deep trenches filled with concrete but dont know if this would be expensive and i also dont know if i would need some forms near the top of the trench ,and how wide would my trenches need to be if my block wall will be made of standard 8"x8"x16" Also wanted to ask about how much do you think the foundation will cost me?






http://img39.imageshack.us/img39/3232/finalplan.jpg (http://imageshack.us/photo/my-images/39/finalplan.jpg/)

[Rich]

I have a calculator located here
http://www.construction-resource.com/calculators/foundation.php
where you can mess with some variables to come up with a rough cost for an all concrete foundation. Typical size for footings under 8" stemwalls is 16x8 unless you have very poor soil bearing capacity.

[Craig-SoCal]

Here's my final floor plan , I'm going to ask the building inspector what he recommomends/requires for a foundation but hav'nt talk to him yet ,
Can anybody recommend a foundation for this? It will be in Iowa were it gets pretty cold sometimes. i want to build on top of a block wall but dont know what would go under the blocks , i was thinking of 4 foot deep trenches filled with concrete but dont know if this would be expensive and i also dont know if i would need some forms near the top of the trench ,and how wide would my trenches need to be if my block wall will be made of standard 8"x8"x16" Also wanted to ask about how much do you think the foundation will cost me?






http://img39.imageshack.us/img39/3232/finalplan.jpg (http://imageshack.us/photo/my-images/39/finalplan.jpg/)

You can get a ball park but you're gonna need a professional to look at that for ya.

[mobilesport]

I have a calculator located here
http://www.construction-resource.com/calculators/foundation.php
where you can mess with some variables to come up with a rough cost for an all concrete foundation. Typical size for footings under 8" stemwalls is 16x8 unless you have very poor soil bearing capacity.

Cool , thanks for the calculator , already has come in handy a few times!
Just curious how do they get the footer 16" wide if the trenches are only 8" wide for the 8" wide stem walls?
http://img40.imageshack.us/img40/3382/stemwallslab.jpg (http://imageshack.us/photo/my-images/40/stemwallslab.jpg/)

[Don_P]

The trench is at least footing width and, depending on depth, can be a good bit wider to allow room for the crew to safely work. The foundation walls are then built and braced, then the foundation walls can be backfilled.

[mobilesport]

The trench is at least footing width and, depending on depth, can be a good bit wider to allow room for the crew to safely work. The foundation walls are then built and braced, then the foundation walls can be backfilled.
Do i have to have a footing? I just ask because another guy said this is how they do it were he lives.
He said
"Someone comes in with an 8" or 10" trencher and goes down 4' deep. Simply fill it with concrete and add some block or a grade beam on top of that. "

Just thinking it would be cheaper if i am able to do it without a footing.

[Rich]

There are areas where they will allow that. With good soil, a single level home will have enough bearing capacity to support it on 8".

[mobilesport]

There are areas where they will allow that. With good soil, a single level home will have enough bearing capacity to support it on 8".

Cool deal, I'll check with the inspector to make sure he's ok with it,
I want to thank all of you guys for all the help , I wouldn't be able to pull this off without it !
I think I'm ready to go for it now I'm just waiting for the weather to get a little warmer

[6wheeler]

I would be willing to bet in Iowa as here in Mn. you will probably have to have frost footings. Even with a stem wall. In our townhome projects where they are usually stem wall/slab on grade, we still need footings. Most of the jobs I deliver to like that are all poured walls. Around here, I haven't seen a block stem wall in years.

[mobilesport]

I would be willing to bet in Iowa as here in Mn. you will probably have to have frost footings. Even with a stem wall. In our townhome projects where they are usually stem wall/slab on grade, we still need footings. Most of the jobs I deliver to like that are all poured walls. Around here, I haven't seen a block stem wall in years.

Aren't Town homes ussually two stories high ?
I was thinking they would let me build it on just a poured stem wall with a blockwall 2 blocks high since its only a single story .
Thanks for the info

[6wheeler]

Aren't Town homes ussually two stories high ?
I was thinking they would let me build it on just a poured stem wall with a blockwall 2 blocks high since its only a single story .
Thanks for the info

Most of them are. But I am seeing alot more single story ones for senior living. And, I guess I should have said 4-plex's and 8-plex's. But they need frost footings. Up here, the footings are poured and then doweled. Then the 4' stem wall forms are set and poured. Then its back filled inside and out. Most of them have Wirsbo floor heating or something similar. So, we open pour the floors without walls so we can either pump the concrete or chute it. I would guess the footings help keep the walls from pushing or heaving.

[mobilesport]

Most of them are. But I am seeing alot more single story ones for senior living. And, I guess I should have said 4-plex's and 8-plex's. But they need frost footings. Up here, the footings are poured and then doweled. Then the 4' stem wall forms are set and poured. Then its back filled inside and out. Most of them have Wirsbo floor heating or something similar. So, we open pour the floors without walls so we can either pump the concrete or chute it. I would guess the footings help keep the walls from pushing or heaving.

Yea our weather is about the same as yours up there in Minnesota so I think your probally right about needing the footings .
Thanks for the info , i kinda know what to expect now.

[Rich]

Footings have nothing to do with frost. The size of the footing has to do with the bearing capacity of the soil. The only thing frost has to do with it is how deep you put the footing (no matter what size it is) to keep it below the frost line.
And even the depth can be manipulated, the code allows for frost free shallow footings so the footing doesn't need to be as deep.
I'm not saying you do or don't need a footing, just that frost has nothing to do with it. People call it a frost footing because typically there is a footing and it has to be below frost line. No matter what you do it should be below the frost line unless you can get away with the shallow footing described above.