Footings for an apron?

[NCtim]

Hey there fine folks,

I'm pouring my pad in a few weeks and I have a question. The pad will extend from the garage entrance four feet in the the front with a slight slope to it. Do I need to dig an extended footer for the front edge of the pad as it adjoins a gravel drive? The pad will be poured inside a block foundation on footings.

Many thanks,

Tim

 

[Stuart in MN]

Generally, an apron needs to have the same amount of support as the building, so they both have the same protection from frost heaves in the fall and spring.

 

[NCtim]

Thanks, that's what I thought. My concrete guys who are also going to form the form the apron said not to worry about it. We don't get much of a frost heave here but occasionally we'll have a couple of weeks in the low twenties in the mornings. It never reaches below an inch or so of top soil. I just thought the extra support measure would be appropriate since the trucks will be here anyhow, what's an extra half yard of concrete for piece of mind?

Tim

 

[topp64]

If it's only an additional .5 yd then sure. I think you're describing more of a thickened edge than a footing. Footings aren't necessary for an exterior apron. The exception being in front of a man door or any entry door, especially when the door swings out.

 

[joes169]

The apron is totally independent of the building, and thus does not need a footing. It should be fully separated from the building pad with expansion joint/felt/etc... Obviously, this is going to add a layer of complexity for your concrete crew, so they're just going to pour it at the same time as the slab w/o a second thought........

 

[yeldogt]

IMO -- I was always told it should be independent. I will say with a new building the earth in front is often disturbed -- and will sink.

Some believe it's best to tie to the slab with rebar

-- I dig holes down to undisturbed earth with a post hole digger ... I do this with any smallish pad built on disturb soil

 

[brownbagg]

yes and no. on a dead weight load no, but as the vehicle enters the slab, they will be a large load on first foot of slab, so yes

also if you want to build on that slab later, the footing be already there

 

[highflier]

On 2 equipment barns I built that house 10-12,000lb machines, I extended the aprons approx 3' at the doorways to meet the gravel and create a transition to the barn.
They step down 1" then slightly slope to the gravel, are 10" thick and 10' wide and are not separate from the building slab, 3500psi concrete.
4 years and no signs of any movement or cracks.
If I were to have made them longer than 3', like 8 - 10' then I would have separated them.
3' apron doesn't have much stability with a lot of weight in a small area.

 

[Firebrick43]

On 2 equipment barns I built that house 10-12,000lb machines, I extended the aprons approx 3' at the doorways to meet the gravel and create a transition to the barn.
They step down 1" then slightly slope to the gravel, are 10" thick and 10' wide and are not separate from the building slab, 3500psi concrete.
4 years and no signs of any movement or cracks.
If I were to have made them longer than 3', like 8 - 10' then I would have separated them.
3' apron doesn't have much stability with a lot of weight in a small area.

It could have tons of stability if you have a properly drained and compacted sub base 12" thick. I think western north Carolina freezes and if so you defiantly want to separate the apron you also want it to be 3/4-1" lower to allow a little bit of lift during freezing weather.

High flier you need to set your location, what you did may be fine in the south were there is no freeze depth or if you heat the apron but up north here on clay soil it would have had serious issues already.

Even if you put it on footers/frost walls unless you heated or filled the space with crushed stone without fines you would have frost heave issues. If you do a footer make sure it's separately poured. A surefire way to Crack a slab is to have it vary in thickness.