Hi,
The wife wants a L shaped seating area with a raised pond & planter as backrest. All concrete rendered. (Damm you Pintrest!)
I've been doing some research & have been advised to use a single skin of 9" (215mm) or 6" (140mm) wide hollow blocks with rebar then filled in with concrete.
It's not huge, the raised back rest sections of the L are:-
Planter 1.2m x 0.6m x @0.9m (4 courses high) half filled with rubble & then soil
Bottom pond 1.8m x 0.6m x @0.9m (4 courses high) with max @ 1.2m3 of water
Top pond (corner) 0.6m x 0.6m x @1.2m (5 courses high) with max @ 0.25m3 of water
The seats are on the inside edges of the L shape, but are not too much of a structural concern as they will be wooden.
The top pond waterfalls down into the bottom pond. We can reduce the depth/volumes of the ponds to reduce lateral forces on the blockwork, but minimum depth needs to be 0.6m to give the fish a chance in winter!
For the footings, the site is on the patio, but a quick check shows it's made of concrete pavers 600mm x 600mm x 25mm with about a 100mm base of compacted aggregate. I've also got a 55mm height difference, so I'm going to have to level that out first.
I don't the think the patio as is, will be strong enough as a footing due to the compacted aggregate base.
Q1. Am I correct in thinking the patio won't cut it as a footing as I understand the min depth for a retaining wall footing should be at least 150mm deep?
Q2. I have to level out the footing, so would a concrete slab on top of the patio be strong enough? If so what depth as it will be >55mm to level out the site.
Q3. Or should I just pull up the patio & lay a 150mm deep footing!
Q4. For the rebars in the hollows, how deep do they need to be below the ground, I presume these are inserted after the blocks are laid & not cemented into the footings?
Q5. Any other suggestions on the construction will be welcomed!
Thanks in advance.
The wife wants a L shaped seating area with a raised pond & planter as backrest. All concrete rendered. (Damm you Pintrest!)
I've been doing some research & have been advised to use a single skin of 9" (215mm) or 6" (140mm) wide hollow blocks with rebar then filled in with concrete.
It's not huge, the raised back rest sections of the L are:-
Planter 1.2m x 0.6m x @0.9m (4 courses high) half filled with rubble & then soil
Bottom pond 1.8m x 0.6m x @0.9m (4 courses high) with max @ 1.2m3 of water
Top pond (corner) 0.6m x 0.6m x @1.2m (5 courses high) with max @ 0.25m3 of water
The seats are on the inside edges of the L shape, but are not too much of a structural concern as they will be wooden.
The top pond waterfalls down into the bottom pond. We can reduce the depth/volumes of the ponds to reduce lateral forces on the blockwork, but minimum depth needs to be 0.6m to give the fish a chance in winter!
For the footings, the site is on the patio, but a quick check shows it's made of concrete pavers 600mm x 600mm x 25mm with about a 100mm base of compacted aggregate. I've also got a 55mm height difference, so I'm going to have to level that out first.
I don't the think the patio as is, will be strong enough as a footing due to the compacted aggregate base.
Q1. Am I correct in thinking the patio won't cut it as a footing as I understand the min depth for a retaining wall footing should be at least 150mm deep?
Q2. I have to level out the footing, so would a concrete slab on top of the patio be strong enough? If so what depth as it will be >55mm to level out the site.
Q3. Or should I just pull up the patio & lay a 150mm deep footing!
Q4. For the rebars in the hollows, how deep do they need to be below the ground, I presume these are inserted after the blocks are laid & not cemented into the footings?
Q5. Any other suggestions on the construction will be welcomed!
Thanks in advance.
