Posted: Fri Oct 30, 2009 5:11 pm
Hi all. New to this great site! I will try to be to the point, it's a little complicated...My friends are having an existing basement level living area extended into their garden to create a new bedroom. Outside the bedroom they want to create a small open light well and paved area by building a retaining wall from the already layed basement slab to 203cm high, ground level. The ground level is flat. From the new paved area to ground level they want to create 4 levels to be tiered planters.
Along the way, they sacked their architect and indeed the first structural engineer for various reasons. They now have their original builder, and a second structural engineer on board.
As I am a Designer, my friends asked me if I would kindly design the planters for them and also do an artists impression of what their light well would look like...which I did. I also did some research on building retaining walls. To the crux...
The builder was intending to build the R. wall using poured concrete re-inforced with steel grid, as per structural engineers drawing, to a thickness of 250mm. On the 2 side walls this would be vertical, but on the bedroom facing wall it would be tiered. The builder then intended building the planters on the R. wall tiers using blockwork. Then the whole lot, walls and blockwork, would be finished in render and painted to give a clean architectural look.
I don't want to create problems where none exist, especially as a little knowledge can be a dangerous thing, but I have suggested to my friends that there are some issues that neither the builder and maybe the engineer have not taken into account. I would like your opinions please on the following:
There was no intention to have a drainage infill buffer zone on the earth side of the retaining walls with any kind of water outlet or weep pipes.
There was no intention of having any waterproof membrane behind the wall. The earth would be up tight behind it.
The planters would be block built onto the tiered step levels on the retaining walls, rendered and paint finished, with no drainage at all.
The builder HAS confirmed that all the render finish would be with waterproofing additive...mmm, not sure about that.
There is the provision for a linear drain to go in just outside the bedroom wall to take water from the small paved area, which at the moment would slope towards the house.
One thing I'm sure of...unless they want to grow bog plants or water lillies in the planters, without drainage they are as good as useless...but more importantly, what would be your thoughts on the points above. I have suggested to my friends that the render finish may be damaged, stained or blown before too long due to the R. wall becoming soaked. The same could also happen to the blockwork render. I am assuming that the engineer has factored in any Hydrostatic pressure complications to the retaining wall, but I will check. But why no mention of drainage to relieve this, nor waterproofing the ground side?
Sorry, I did end up waffling a bit! Look forward to your replies!
Shimmy.
Along the way, they sacked their architect and indeed the first structural engineer for various reasons. They now have their original builder, and a second structural engineer on board.
As I am a Designer, my friends asked me if I would kindly design the planters for them and also do an artists impression of what their light well would look like...which I did. I also did some research on building retaining walls. To the crux...
The builder was intending to build the R. wall using poured concrete re-inforced with steel grid, as per structural engineers drawing, to a thickness of 250mm. On the 2 side walls this would be vertical, but on the bedroom facing wall it would be tiered. The builder then intended building the planters on the R. wall tiers using blockwork. Then the whole lot, walls and blockwork, would be finished in render and painted to give a clean architectural look.
I don't want to create problems where none exist, especially as a little knowledge can be a dangerous thing, but I have suggested to my friends that there are some issues that neither the builder and maybe the engineer have not taken into account. I would like your opinions please on the following:
There was no intention to have a drainage infill buffer zone on the earth side of the retaining walls with any kind of water outlet or weep pipes.
There was no intention of having any waterproof membrane behind the wall. The earth would be up tight behind it.
The planters would be block built onto the tiered step levels on the retaining walls, rendered and paint finished, with no drainage at all.
The builder HAS confirmed that all the render finish would be with waterproofing additive...mmm, not sure about that.
There is the provision for a linear drain to go in just outside the bedroom wall to take water from the small paved area, which at the moment would slope towards the house.
One thing I'm sure of...unless they want to grow bog plants or water lillies in the planters, without drainage they are as good as useless...but more importantly, what would be your thoughts on the points above. I have suggested to my friends that the render finish may be damaged, stained or blown before too long due to the R. wall becoming soaked. The same could also happen to the blockwork render. I am assuming that the engineer has factored in any Hydrostatic pressure complications to the retaining wall, but I will check. But why no mention of drainage to relieve this, nor waterproofing the ground side?
Sorry, I did end up waffling a bit! Look forward to your replies!
Shimmy.
