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westernmdlawn
11-05-2006, 12:28 PM
Hi all, I have a question about retaining wall base preparation. I understand the process thoroughly for normal conditions, and for walls under 4' high. What I am unsure of is how freeze / thaw affects the sub base soil for a retaining wall. I understand that we are to install 6-10 inches of crushed limestone (compacted in 2" lifts) for the base, then use sand to level the base course. So the excavation would need to be done 10 or so inches below where you want the base course to lie. Here's my question - here in Western Maryland the frost line is at or around 3 feet below ground. So, unless you dig down 3 feet the soils below your base (6-10" of crushed limestone) are prone to freezing and thawing. So would this not make your base vulnerable to heaving and settling? Shouldn't we be excavating and installing base material 36 inches in my area?

I haven't yet had a chance to go to the NCMA certification course, or else I'd already know the answer to this question. I'll be going before spring for sure.

Mike33
11-05-2006, 02:58 PM
Dont worry about it Brian, these walls are to contract with freezing and thawing. Just go to solid ground and here in our area sometimes that is not to deep. Get away from the sand though i can show you a wall in Braddock estates thats failing due to the use of sand. Call me if you like.
Mike

westernmdlawn
11-05-2006, 08:44 PM
Thanks Mike - The product manufacturer specifically recomends the use of sand. What else could you use? Stone screenings / dust? What happens with sand?

Mike33
11-05-2006, 10:23 PM
are you talking walls or pavers? You know i dont do pavers and i hate to comment on them but i do know you use sand for them. Walls is no no! If your talking walls what product? The only thing i can think with out great thought is the sand moves down in the gravel causing the block to settle. I seen a wall in Braddock estates across the street from where i built one 3 years ago that look like crap. I talked to home owner and he told me he put sand over the gravel. Wall looked good at time with in 6 months wall settled and looks bad. learn to level the block on the aggregate it might take longer but gives better job. I think some guys does this method so they can level base course easier which you can but i dont like the out come. Sometimes the easier and quiker way is not the best way. Do you have your snow accounts in order for frostburg area/ Back to your question stick with 57s or 67s.
Mke

westernmdlawn
11-05-2006, 10:45 PM
Well, I've been using EP Henry - never tried anything else. They call for sand to level the base course. It is only like 1/2 inch or so. I don't think sand compacts very much - it does a little, but not much. As for it settling into the aggregate - I'll find the answers out soon at the NCMA. I just want to do whats right. I don't want even one project failing or looking bad, you know? Doesn't take much to get a bad reputation, especially in a small town.

Yes... got most of the snow accounts in order. I dumped a couple of residential ones and picked up a few commercial ones (gotta love them commercial ones - plow and salt = $$$). I now have 3 plow trucks and a bobcat with a 7.5' plow. I was thinking about getting pro-wings on one of my trucks 7.5 Western Steel blade. If they work half decent, it would be well worth the money (around 200$ I believe). I'm concerned about my spreader. It is a cheap Buyers unit. This will only be its 3rd season, but you know how that darned salt tears everything up especially electrical stuff. Additionally, I'm not sure if one spreader is enough for the work I have to do. I don't want another tailgate spreader, if I get a new one, I want to get a V box spreader - but what kind? Who knows, there is alot to choose from (Hiniker, Buyers, Myer, Western, SnoWay, etc.). Did you find any good deals on salt this year? Last 2 seasons I've been using Southern States 80# bags at around 5$ each (if you buy it by the skid). I haven't bought any yet.

Mike33
11-06-2006, 10:53 PM
Thats about the going price. The buyer is a good spreader i own 3 of them. I did go to a boss on my main truck just do to convience of power on and power off no muscle work. That amount of sand wont hurt you, i was tinking you were talking about 4-5". Some guys even use a splash of limestone dust. We go gravel all the way.
Mike