Erosion Under Concrete Patio

Erosion due to poor water drainage and plumbing leaks.

Erosion under concrete patio.

Voids can lead to a weakness in the slab causing dips in the surface tilting or cracks and breaks. Some amount of cracking is to be expected during the life of a concrete slab. Concrete slabs can develop voids from a variety of reasons ranging from sliding soil beneath the slab displaced because of a lack of proper compression to water erosion slowly washing away the soil over time. To remedy the situation i used the apparatus shown in the drawing to pack mortar into the cavity.

There are various reasons why voids form underneath concrete slabs. Improper water drainage can cause the issue. How to prevent soil erosion around a patio erosion causes. To repair you ll need a form.

So what should you do if you notice erosion around or under your concrete slabs. Steps to control patio soil erosion take preemptive preventative measures. Some nasty runoff eroded a cavity under the edge of my concrete patio and i became concerned about the lack of bearing along its edge. If the pipe is beneath the concrete the structure will no longer have firm dry soil underneath it just mud.

An unusual amount of cracking spread over a large area isn t normal however and usually indicates that the slab is sinking. Sooner or later the slab would break off where the soil had been washed away. Another issue that could cause erosion under concrete is a burst water pipe. Indeed the best way to address soil erosion is to try and prevent it from ever.

Bury an aluminum flashing or redwood or other suitable material a couple of inches deep and about an inch from the concrete edge allowing it to extend above the bottom edge of the concrete approximately an inch. Many people will attempt to fill these voids with dirt sand or gravel and while something is better than nothing none of these solutions are able to generate any upward pressure on the concrete so not much support is possible. Erosion the gradual loss of soil to rain wind or runoff following a rain can create havoc in a sloped yard. While erosion is a commonly cited culprit there are also naturally occurring reasons for the presence of voids under slab foundations.

Depending on its construction a patio is either of limited porosity or not porous at all. In fact most slabs are constructed with control joints along which cracks are supposed to occur. Let s say that it s already too late to install some preventative measures or that you did. Left unchecked erosion can wash away soil on a slope cause channels in the slope s.

Add ground cover.