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retaining wall

forkball's picture

I am a DIY'er, and am getting ready to put in a low retaining wall (max ht is 2'), approx 50' long. It will be butting up to a concrete pool deck. I have two questions, if anyone can help: 1) Do I need to put anything between the concrete retaining blocks and the poured concrete slab, or can they be butted up against each other?  Question 2) For this height wall, do I need to run drain pipe in the gravel behind the retaining wall?  I am using AB Block for the wall, no mortar to be used. 

I appreciate any advice!

Retaining walls move, so you (post #207032, reply #2 of 3)

Retaining walls move, so you need to be prepared for that.  And if you dig down around the slab you may find that there are lumps of concrete projecting out.  So it may not be advisable to butt up directly to the slab, but rather have some pavers or some such in-between.

(Also note that you should not dig too near the slab, to avoid undermining it.  And you need some space behind the wall for gravel.)

if you put moderately coarse gravel behind the wall, and cover that with filter fabric, you probably don't need a drain pipe in such a low wall of stacked block.

Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

A great point I never thought (post #207032, reply #3 of 3)

A great point I never thought about in regards to the probability of excess concrete preventing a clean abutment to the slab. I am thinking even using a narrow transition of some decorative gravel? The excavator did dig an extra 12" behind where the wall will be, and my back will thank him later.  Because of proximity to the house and the size (length) of the wall, seems like maybe running drain pipe along the back side of the wall could avert potential issues in the future.

Thank you both for the input!

fork (post #207032, reply #1 of 3)

It may be short, but it's got some length.  If the land above is swaled to this area, I'd use stone and pipe to relieve the water.

Your call.

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