# How to add footing and foundation to existing foundation?



## ptcamaro (Mar 29, 2008)

Hello All,
I will be adding a 22x19 addition to my 36x24 house. House sits on 7' foot high basement foundation and addition will be on a crawl space foundation. Frost line is 3 foot. Footing will be 16"x8" and concrete block wall on top. From the top of the existing foundation to ground is 16" . 
So, after digging 3' for top of footings and 8" deep footing the new foundation hight will be 5'

How would you add/merge the new footings and walls to old basement wall? 
How much rebar needed for 16"x8" footings?

New foundation will be on undisturbed soil.

Thanks to all taking the time to answer.


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## Gary in WA (Mar 11, 2009)

This will all be in detail on your plans you should have submitted to your local Building Department. 

Some people skip this step and some end up ripping it out later (usually when they try to sell), because the house size, lot size, setbacks, additions, etc. is public information with the County.

Be safe, G


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## ptcamaro (Mar 29, 2008)

GBAR in WA said:


> This will all be in detail on your plans you should have submitted to your local Building Department.
> 
> Some people skip this step and some end up ripping it out later (usually when they try to sell), because the house size, lot size, setbacks, additions, etc. is public information with the County.
> 
> Be safe, G


thats why I'm asking to put on plans. :wink:


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## Daniel Holzman (Mar 10, 2009)

You do not state your location. Details of foundation design are a function of the building code, which varies state to state. Also there may be local building code requirements. Therefore, it is impossible for a DIY chat room to offer you correct information on your situation.

I assume you do not have an engineer or architect designing your plans, else there would be no need to ask about rebar etc. So I assume you are doing your own design. The easiest thing to do would be to purchase a copy of the building code for your area, read the section on foundation design, then discuss what you are doing with the local building inspector, who will likely be very happy to offer you pointers on what should be on your plan.


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## ptcamaro (Mar 29, 2008)

I'm in NJ. 16x8 footing is standart around here. 
All I'm trying to understand what is acceptable to join the new foundation to old and what rebars used for that footing size. I like to show something in the planbefore I submit the plans. I know building department will correct what is needed.
Thanks.


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## Paragon (Jun 14, 2009)

PT,

I hope that you understand it is hard for us to tell you what is common in your area. could be 4 bar could be doweled could be a lot of different things. You need to talk with your local building officials and see what is common in your area or hire a professional to do the work for you. You could hire an engineer to work up some plans for you and then do the leg work yourself. 

I never advocate a person taking on a project they do not fully understand as it provides problems down the road. The professionals that DO know your codes and standards in your area are the ones to ask and not here. If you don't know find those that do that is the purpose for them and the reason you pay them the money you do not so that they can dispense free information but so they can earn a living.

Good luck and be safe!


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## Mop in Hand (Feb 5, 2009)

"I know building department will correct what is needed." Do not assume this. Most building departments ( at least in my state) have a disclaimer on thier permits. You or the engineer will be responsible to make sure your drawings are correct not the building dept.


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