I had a contractor pour my frost footings for a garage/apartment...I was quoted for 36 in. footings but while digging down to the sleeves to run my plumbing, I discovered, they only poured about 24 in. footings. When questioned, he responded that you also have to add the height of the slab to footings for your total....is that true?

 

When you say 24" footing are you referring to the thickness of the concrete in the footing or how far the bottom of the footing is below ground?

 

thank you for replying, the depth below the ground of the footing is 24 inches (the width is 12 inches)

 

The frost line is at the bottom of your footer. If I understand correctly your contractor is right. Footers normally only need to be 8" thick but they have to go down to the frost line

 

thank you for your reply. In my area the frost line is 20 inches deep. I've read that I need footers 10 inches below that. So 24 inches of footer depth + 4 inches of gravel depth + 4 inches of concrete depth should be sufficient for the frost protection, if i'm understanding correctly. At least i should ask for a discount for getting 24 inches of footer rather than 36 inches.

 

I assume the slab concrete will pour down onto the footers, the amount of concrete should be the same.

 

Thank you MarkSr. I'm sorry, I'm not understanding the last reply. Could you expound?
What I'm certain happened: the footings were dug on a friday and then we got a torrential downpour over the weekend. Dirt fell into the trench and was not removed before pouring the footings, So instead of 36 inches deep, the footers are 24 inches deep. What was concerning me was his comment that the footers would be deep enough if you count the concrete we are putting on top. (I'm skeptical that's he's just making an excuse)

May I ask another question. He wants to pour the slab without putting down gravel. In researching, i get mixed feedback on that idea. Is there a best-practice?

 

So the footers didn't go as deep? you shouldn't pour footers over loose dirt.
Gravel helps with drainage under the slab along with being a fill that compacts better. Hard to say without knowing your property if it's needed or not.

 

yes, that's correct, footers were not as deep as intended. I'm guessing the torrential rains caused the trench to fill in somewhat. I'm certain they didn't followup and clean out any extra dirt/mud that built up on the bottom. The project is on property that I don't currently reside on yet, i was very surprised when he called and said that the footers got poured so soon after heavy rains. Should i be concerned if they were poured in wet soil?
Sorry for so many questions. Never had the chance to build before so everything is new and daunting.

 

The reason for footers not being poured over fill is the possibility of the concrete settling. It might be ok but it's hard to say. Is this structure permitted and inspected? if so, you might want to bring these concerns to the attention of the inspector.