jdwilson44
05-22-2005, 10:11 AM
Just found this forum after doing some searching on the internet - looks like a lot of useful information here.
I am in the process of building a 28x40 garage/barn on my property and have a few questions about putting the foundation in properly. The area where the garage will be located slopes down about 3ft in 40ft. There are a few things I know about putting in a proper foundation and few things I am not sure about. I know for instance that the frostline is about 42" below grade in this area, I should be setting the footers on virgin - non-organic soil, and that I should have approximately 1ft of foundation exposed above grade so that I don't have wood too close to the ground for termine/carpenter ant reasons. The reason I have questions is that I am in the process of doing the excavation for the foundation hole myself and would like to know how deep I should be going to get down to proper soil for the footings.
Because of the slope of the land and way the soil is layered I am not sure I am going deep enough on the lower end of the excavation to get down to proper soil. The soil in this area consists of a 6" - 1ft layer of topsoil, about 1ft of a loamy medium brown soil that does support plant growth, and then a light tan layer of sandy/claylike earth under that. I believe that the lowest layer is good for pouring the footers but I haven't consulted a soil engineer on this. My problem is that because of the slope of the land I am not sure what height of foundation wall I should be aiming for - I believe that a 6ft wall with a 1ft high footer will place the top of the foundation approximately where I want it as well as having the footer into the proper soil on the lower end -but I have not finished the excavation yet so I am not sure on this. If on the lower end of the excavation I find I need to go deeper to get to proper soil I am better off going with a step foundation or should I just excavate all around for a 7ft wall ? . Do most foundation contractors have forms to do 6ft, 7ft and 8 ft walls? Or should I maybe just be aiming at putting an 8ft wall to make it simpler? The inside of this foundation will be filled up to grade for the garage floor and on the lower end I will be backfilling around it so the footer will definitely be below the frostline one way or another.
I am in the process of building a 28x40 garage/barn on my property and have a few questions about putting the foundation in properly. The area where the garage will be located slopes down about 3ft in 40ft. There are a few things I know about putting in a proper foundation and few things I am not sure about. I know for instance that the frostline is about 42" below grade in this area, I should be setting the footers on virgin - non-organic soil, and that I should have approximately 1ft of foundation exposed above grade so that I don't have wood too close to the ground for termine/carpenter ant reasons. The reason I have questions is that I am in the process of doing the excavation for the foundation hole myself and would like to know how deep I should be going to get down to proper soil for the footings.
Because of the slope of the land and way the soil is layered I am not sure I am going deep enough on the lower end of the excavation to get down to proper soil. The soil in this area consists of a 6" - 1ft layer of topsoil, about 1ft of a loamy medium brown soil that does support plant growth, and then a light tan layer of sandy/claylike earth under that. I believe that the lowest layer is good for pouring the footers but I haven't consulted a soil engineer on this. My problem is that because of the slope of the land I am not sure what height of foundation wall I should be aiming for - I believe that a 6ft wall with a 1ft high footer will place the top of the foundation approximately where I want it as well as having the footer into the proper soil on the lower end -but I have not finished the excavation yet so I am not sure on this. If on the lower end of the excavation I find I need to go deeper to get to proper soil I am better off going with a step foundation or should I just excavate all around for a 7ft wall ? . Do most foundation contractors have forms to do 6ft, 7ft and 8 ft walls? Or should I maybe just be aiming at putting an 8ft wall to make it simpler? The inside of this foundation will be filled up to grade for the garage floor and on the lower end I will be backfilling around it so the footer will definitely be below the frostline one way or another.