Spec for retaining wall?

[James Gifford]

I'm bidding out a large landscaping project that involves a fair-sized retaining wall to be built of keystone blocks. It's about 115 linear feet, varying from about a foot (two courses) to four feet over its run. I have estimated its average height at about two feet.

One bid was returned with the spec for a "400 SF" retaining wall - I assume he means 400 square feet. How does a square footage measurement apply to a block retaining wall? If he means the face area of it, he's off by almost double.

Is this in any way a standard way to spec a retaining wall? I'd like to know so as not to sound too stupid in discussing it with him. (For reference, he also quoted at least 50% too much fill and 30-40% too much sod, even though I gave him surveyed, CAD-drawn figures to work from. So I'm not 100% sure he knows what he's doing, here...)

Thanks.

[James Gifford]

Thanks, I'm doing just that. We had six bids originally and they varied so much I took a time out and surveyed the site, then asked for revised bids based on the specific measurements and requirements. (Fill estimates varied from 50 to 110 yards, sod from 3000 to 5400 SF, etc.)

Even accounting for the sub-grade portion and some waste, I think he's overspec'd the wall by about 25% (which is a couple of grand). I'll wait for the other bids to come in and go from there.