Retaining wall question?

[311Hemi]

I am looking at building a wall similar to the one in the picture. Most of the wall would be 1 block tall with a cap, but I will be wrapping a corner of the house that has a slope where the wall will get around the height in the picture. I will have a few corners of the house that will be around the height in the picture, the house is a walkout sloping down to the back yard.

Do I need to install any kind of drainage behind the wall for an installation like this? It's all sand surrounding the house and I will be making sure it is slopped properly.

[Eric Wettschreck]

Weather you NEED to instal some drainage I can't answer.

However, I've seen my share of retaining walls blow out in the winter due to lack of drainage. If it were me, I'd put in some drain tile.

[luveyesdoefmn]

Hemi, I build them for a living. 3/4 inch rock one foot behind wall. NO drain tile. Built a ton of walls. Use 4 inches class V for base. Good to go.

[311Hemi]

Hemi, I build them for a living. 3/4 inch rock one foot behind wall. NO drain tile. Built a ton of walls. Use 4 inches class V for base. Good to go.

Do you use fabric behind the 3/4 rock, between the rock and soil? I assume the rock goes from the bottom block all the way up to just below your finished surface covering (mulch/stone/etc)?

Do you need drainage on short walls, where a single block and cap are used mainly for a decorative border? Would I need class 5 there as well?

[luveyesdoefmn]

I would never advise putting fabric behind the wall ever. You could probably get by without class V if the base is good sand like you said. On the wall wrapping the corner I would feel better if you put the 3/4 behind it. Make sure the sand is packed well with one of those hand tampers. My advise to anyone doing walls is that Ive built hundreds here in the cities and never had one fail,thats because I am liberal with the rock behind. Make sure you bury at least half the height of the base course. Any Questions call me. Keith Wendorff, Wendorff Construction 612 282 5114 Drain tile is again not needed.

[311Hemi]

Thanks Keith, that all makes sense. I have a hand tamper so that will not be an issue, it is all pure sand around the house.

I assume this is a representation of how your walls are built, with the compacted backfill being the 3/4 rock?

Do you put anything [fabric] over the top of the 3/4 rock before adding soil or whatever back on top of it to prevent that from going down into the rock?

Does the 3/4 drainage rock go right up against the foundation wall of the house, or do you add some plastic against the foundation wall to keep water away from it? Are any weep holes needed for drainage?

[TruthWalleyes]

That's how I've built them. No fabric over the rocks.

[CarpinMNRiver]

Use class 5 for the base if you want it to stay level. A wall that height does not require drainage rock but if you use drainage rock I would tile it. It really doesn't need it though.

[311Hemi]

If I order class v, do I need to specify anything in particular?

I need to order a full load of base for a patio I am going to install, and was going to order 3/4 minus crushed limestone. Is class 5 any different from that, because the place I called said they had both 3/4 minus and class 5 which is more of what they use on country roads?

Which would be better under a paver patio? Class v is much cheaper than 3/4- limestone.

[311Hemi]

Never mind, I went with the 3/4 minus limestone.

[311Hemi]

Hemi, I build them for a living. 3/4 inch rock one foot behind wall. NO drain tile. Built a ton of walls. Use 4 inches class V for base. Good to go.

Do I just use 3/4 limestone, or is there a certain kind of rock to buy?

[Surface Tension]

Behind the retaining wall you'd use 3/4 washed or crushed rock.

Whichever your pit has.

[311Hemi]

I got started on the project over the weekend, and have a few more questions.

Do I glue the blocks together, they will be anywhere from 2-4 courses tall (8-16") in most areas not including the cap block. A few areas on the side of the house will push 36" with 4x12 block, so I will be gluing those areas and back filling 12-16" of crushed gavel.