concrete foundation with a crawl space
I am planning on adding a front room to my house and it requires a foundation to start. Live in Ohio, so I understand that a certain depth has to be dug for the foundation and footer. Now, is there a precast foundation that can be done without doing concrete block? The room size is 8x12 and so the foundation will be attached to the existing foundation on the house with I assume special steel bars. I am not planning on doing a basement, so that is not being planned. Is this a process that would be too expensive to be done, since only 3 sides are being done? I am also planning to do a prefabricated walls. Hopefully, this will save on labor costs.
Am I over exaggerating on this type of planning?
Please let me know.