Liability Insurance And Worker’s Compensation insurance certificate.
If someone is hurt on your property and your contractor does not have work comp, you will likely be responsible. Always ask for a current copy of any contractor’s insurance certificate.
Critical Information and Questions
Will you warranty your work? If so, for how long? Warranty in writing?
Will you put grid in the wall? (3’ tall and higher) then ask what kind of grid, to see if they know. If they are experienced, they will know.
What type of compaction equipment will you use? (Should be using equipment of some sort, like a Plate compactor, a Jumping Jack, a Sheepsfoot compactor)
Grid and compaction are key. If they aren’t planning to use them or don’t know how to correctly install them, your wall will likely fall down.
Will you use rock behind the wall? (If the answer is no or not much, you should not hire them. Period.)
How do you construct the footing? (Should be 6-8” of Compacted Rock depending on soil conditions)
Unless you know what questions to ask and insist on, you may very well end up paying twice for your retaining wall. We receive 2-3 calls monthly from consumers who went with the low bid and their retaining wall has fallen down. Ask for references for the same type of work. Someone who works in the field such as irrigation, tree and landscape companies aren’t necessarily qualified to construct a permanent global stability structure. It is to your benefit to do your homework.
Retaining Wall Costs
While it is tempting to just go with the low bid, it is mostly true that You get What You Pay for.
Reputable installers should be pricing walls between $25- $60 per square foot. To figure your square footage multiply the length by the height then by the square foot price (100’ long by 4’ high= 400 square feet x $30= $12,000).
Things that affect the Cost per Square Foot
If you are replacing a rotten timber wall, the costs for removing, hauling off and properly disposing of the timbers will put you in the $30-$65 range.
Access to the construction zone is also a huge factor in cost. Lack of access results in hand work and higher costs.
The lower end of the range of $25 per square foot or so, would be for large retaining walls of 1,200 square foot or more.
Materials also play in to the square footage cost
The lower end of the range will be for Soil Baskets, Rockwood, Cornerstone or Anchor Diamond in Gray or Tan. Using color blends or scored block increases the costs. Higher cost materials would be Heritage Stone, Creekside or masonry retaining walls. Availability varies greatly.