Fixing a Sinking Concrete Stoop

traderm

I've got a concrete stoop that has sunk several inches since it was installed back in the 1950's.

I've heard about using a mud jack, but think the best route is to remove/replace. A handyman I've considered hiring said he would attach a new stoop to my house foundation with rebar so that it couldn't sink in the future. Though I'm certainly no expert, I don't like the idea of drilling into my foundation, is seems like I'm opening the door to future issues.

Your thoughts?

Ron6519

I would sink sonotubes against the house and at the front on the stairs to act as supports for the new stairs. If they're pre cast, you would prepare the base as usual and place the stairs on the piers. The number and size would depend on the size of the staircase.
Ron

yesitsconcrete

it all depends on the prevailing frost levels you experience,,, i wouldn't attach anything to the house - that's why they make isolation jnt mtl,,, your handyman's no expert, either

jomama45

I definately agree with the last 2 posters, don't rebar into block foundation. It will only egg out/destroy the hollow concrete block. And never under-estimate the power of frost- it will win every time. I would definately get a quote from a reputable concrete contractor if this stoop is somewhat heavy duty as I've seen block displaced in the basement already from "rough" removal of heavy concrete outside.

Daniel Holzman

Your stoop almost certainly settled due to poor foundation preparation (for the stoop that is). After you remove the stoop, you will likely find that it was placed directly on grade, with little or no preparation of the base. If you want a concrete stoop that will not settle, you need to prepare a proper base, which can be done in a variety of ways.

One simple way is to excavate to frost depth, backfill with coarse sand or gravel, and compact in maximum six inch lifts. Frost heave does not occur in gravel or coarse sand, it is a problem in silty soils, fine sands, and certain types of clay. Therefore, a foundation that consists of coarse material with no fines, that is properly compacted, will not settle or be subject to heave.

Alternatively, as previously suggested, you could support the stoop on sonotubes,however then you will need a reinforced concrete stoop, else it has the potential to crack between the sonotubes. This could occur because the sonotubes (excavated to frost depth) are not going to settle, whereas the soil between the sonotubes could settle, leaving the stoop acting as a beam between the sonotubes. If you are constructing a concrete beam, it needs to be reinforced.

If you don't really care about settlement, you could excavate down say 2 feet, backfill with gravel, compact, then build the stoop on top of the gravel. Your stoop would then be subject to a relatively small amount of settlement, and potentially some frost heave, but you would avoid the need to dig quite as much.

In no case would I attach the stoop to the house foundation by rebar or anything else.