||03-21-2012 10:16 PM
Erosion and a void around slab edge
I have lived in my house for four years and have slowly discovered that it has been pieced together over the years.
The side (right side in the drawing I attached) of the house sits on a slab with no footing. When we moved in, there was some minor erosion around the slab edge and the chimney had a slight tilt - in four years, that hasn't changed (no new cracks in the chimney, no other visible signs of any settling - inside or out).
I noticed a few weeks back that some finish work around the rear corner of that side of the house was cracking. I pulled it back to discover that there is also a slab back there, but this area has a nice-sized void under the slab edge. There is probably a 3'x3' area of unsupported, 'floating' concrete. The picture I included doesn't show that, but you can see the edge of the slab with darkness underneath.
Luckily, this part of my house is extremely light construction - a shed-style roof and a single story...so not a ton of weight. But it obviously freaked me out.
I have received a few bids on different ways to fix everything (including the section with just the minor erosion and tilting chimney). My problem is that everyone I have talked to has a particular product that they are trying to sell me.
The two basic options that have been presented to me are:
1) Slabjack everything for a total cost of about $2000
2) Reinforce everything with a combination of slab piers and push piers for about $11000
I am looking for the right balance of cost and effectiveness. I know that piers will solve the problem forever, but doesn't it seem like overkill for the areas that just have minor erosion that hasn't changed in 4 years? And is slabjack a bad idea for large voids?
Also, I should mention that we can assume that the causes of the erosion (poor drainage) will be fixed by the time I get the foundation work done. We are having a french drain installed that will get the water away from the structure.
Thanks for honest opinions!