View Full Version : Another retaining wall question

10-09-2005, 10:20 PM
I have landed a large general landscape job and part of it is building a 2ft tall retainging wall that will have about a 1000 sq ft paver patio running along it's edge. There will be a 2ft wide garden space between the patio and the top of the wall. The customer wants to use a natural field/granite stone that I am contemplating dry setting. I will definitely use a gravel drainage system behind the wall under the garden space. I am wondering whether you guys think this wall should be dry layed or mortared with vertical rebar, etc. Also should I pour a concrete footer or can I just use a crush and run/ road base footing material. I have done small walls before, this one will be approx 60ft long with a set of steps in the middle of it. Thanks for any advice.

10-09-2005, 10:56 PM
If you dry lay, use the same base you would for a SRW. If you use motar and rebar, you need a concrete footing.


10-11-2005, 07:56 PM
You can dry lay the stone wall and back pack the entire wall with mortar. This gives the wall a dry laid natural look with the stability that will hold the bank or patio. First lay down some gravel dust(over top 57's if you need them) to create a bed for the stones, as you set each stone make sure it is locked from behind with smaller stone. When you finish laying your stone, mortar the entire back side of the wall, this locks the entire wall together create a stable cohesive unit. This ensures the wall will not move from expansion and contraction due to the freezing and thawing of the soil. If the wall is long you may need a mid point drain relief underneath the wall, that connects to the main drain tile behind the wall. Once the mortar has setup lay your drain tile behind the wall and back fill with 57's. After you back fill with the gravel lay rosin paper or newspaper over the gravel and then fill will soil and amendments, the paper create a barrier between your drainage system and the soil.

Hope this helped

10-11-2005, 07:59 PM
Can you let me know what "57's" are that you are refering to? The rest I get and will use your advise. Should I use a type N mortar?

10-11-2005, 09:11 PM
57's is the size of gravel produced by aggregate quarries in virginia. This is the type of gravel that we use all types of drainage problems. It is a combination of two different gravel sizes 5's and 7's. It might be call something different in Ma. We use portland cement and if you have extra gravel dust you can use that instead of sand in your mortar mix. Here's a little side note: My dad grew up on the south shore of Boston in a town called Cohasset, Ma. We still have a lot of family up there and I love going up to visit, it's a great area.


10-11-2005, 10:08 PM
#57 or #6 used in my area. Both are drainage gravel.

10-12-2005, 06:23 AM
Hey Adam, Now I get it. Here we have 3/4", or 1 1/2" native stone, bluestone same sizes, etc. Numbers like you have would be easier. I will be using the 3/4" for the drain gravel.
Cohasset is very nice. Just cold as you know what in the winter! Thanks again for the advice.