Hello everyone,
I recently built a new house and am now filling my garden with topsoil. On the street side, I have 18-25cm (7-10 inches) of fill to reach the terrace level.
My plan is to build a retaining wall using masonry blocks.
I would like to have a foundation trench excavated as part of the filling process. It should be 50cm (20 inches) wide and about 20-30cm (8-12 inches) deep (topsoil layer).
Then I want to compact the sand and raise/compact it with a mineral mixture to height, and set the blocks in lean concrete with a back support.
Would this be sufficient for 2-3 courses of blocks (30-50cm / 12-20 inches + 10cm (4 inches) in lean concrete), or do I need a proper foundation of 40cm (16 inches) or more with pouring—even at this low height?
Best regards
I recently built a new house and am now filling my garden with topsoil. On the street side, I have 18-25cm (7-10 inches) of fill to reach the terrace level.
My plan is to build a retaining wall using masonry blocks.
I would like to have a foundation trench excavated as part of the filling process. It should be 50cm (20 inches) wide and about 20-30cm (8-12 inches) deep (topsoil layer).
Then I want to compact the sand and raise/compact it with a mineral mixture to height, and set the blocks in lean concrete with a back support.
Would this be sufficient for 2-3 courses of blocks (30-50cm / 12-20 inches + 10cm (4 inches) in lean concrete), or do I need a proper foundation of 40cm (16 inches) or more with pouring—even at this low height?
Best regards
W
WilderSueden14 Mar 2024 17:48I would use at least 20cm (8 inches) of concrete, preferably 30cm (12 inches). That way, you can skip the back support.
Alternatively, the mentioned dry stone wall. However, it should be built with different stones and sloped backwards.
Alternatively, the mentioned dry stone wall. However, it should be built with different stones and sloped backwards.
WilderSueden schrieb:
I would use at least 20cm (8 inches) of concrete, preferably 30cm (12 inches). That way, you can skip the back support.
Alternatively, the mentioned dry-stone wall. But that should be built with different stones and slanting backward. So, you mean excavate the topsoil layer, compact the sand once, then pour a 30cm (12 inches) deep by 20cm (8 inches) wide screed concrete base, and after it dries, set the wall stones in lean concrete without any support?
Best regards
W
WilderSueden17 Mar 2024 21:50You can basically skip the lean concrete. Just set the blocks in a thin mortar bed. Use vertical reinforcing bars in the foundation to connect it with the blocks. Also, place a reinforcing bar inside the blocks to connect them to each other. That should hold well.
Okay, so a 20x40 foundation with one layer of reinforcement in the foundation (every second block should be enough?), and set the first course in masonry mortar. Since we might add a 1.40m (4 ft 7 in) fence on top later, up to where should the blocks be concreted? Or should it be fully filled and then drilled later?
W
WilderSueden18 Mar 2024 11:53Ideally, you should set the fence posts in concrete right away. Otherwise, I would fill them completely and anchor them with anchors later. For the reinforcement bars, I would use one bar for every half brick, since they’re not that expensive. However, with the height, you could probably save by using fewer bars.
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