Retaining Wall

[Judith Birkett]

Hello

(Please see attached)

I am looking to build a single storey rear extension. My property is on a slope. (sloping from one side (left) down to the other (right)). I was looking to construct using a timber suspended floor like the original property.

My question relates to the retaining wall holding back the bank on one of the sides as I would be digging into it.

Basically, I was going to use the sub walls of the extension, Solid Dense Concrete Block 7.3N, to hold the bank back. (bank is about 1.2 m in height at highest point), is this ok, and would it get through Building Control. If not, what is a more appropriate way of doing it?

Also, can this be designed by an Architectural Technologist, or would I need to employ a separate Structural Engineer.

 

[freddiemercurystwin]

1200 high would need a proper retaining wall to be designed, reinforced concrete or mass blockwork such as the following spring to mind, a standard cavity wall like you've drawn won't rub. Building Control will likely expect an SE to have been employed to design the retaining element. A rule of thumb for a mass retaining wall is that the thickness at the base should be about 1/3 of the height.

 

[^woody^]

1.2m at the highest point implies that the soil to be retained is lower elsewhere?

Either way, a retaining wall has the greatest load at the bottom third or thereabouts of any bank, so thats 400mm, so no SE required. The pertinent thing would be to design suitable waterproofing, insulation and condensation prevention.