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Concreteing behind a retaining wall advice!
phil24_7
Posts: 1,535 Forumite
I have a retaining wall in may garden that I need to back fill with concrete.
The wall is 6820mm long, 1350mm high and is at an angle to the wall/ground behind that I need to retain. The depth of the void goes from 285mm-450mm.
The wall is built on top of a 200mm, C40 base, reinforced with 2 layers of A393 mesh with starter bars (10mm I think) coming up from the base behind the wall and A393 mesh fixed to these in the void. The mesh is chemifixed into block-built steps at either end of the wall and the wall is fixed at both ends using starter bars and fixed every course.
The wall was built in the summer and the area of the void is just under 3.4m3.
3.4m3 is rather a lot to be lugging around the back of the house, mixing in a drum mixed and then lifting and pouring into the void. It is doable but would be around 200 bags in total and would take most of the weekend with me an a helper or 2. Bulk wouldn't be much use as there are too many steps to traverse with a barrow so would need to be hand-balled.
Can I pump it in, will the wall take it? If not what about if I dropped it to 4 courses (2.25m3) and then do the last m3 by hand?
If both of these options are a no go, how could I go about strengthening the wall to take the pressure? I could get curing accelerators put in the pumped mix so that it would only take an hour or so to go hard.
Regards
Phil
The wall is 6820mm long, 1350mm high and is at an angle to the wall/ground behind that I need to retain. The depth of the void goes from 285mm-450mm.
The wall is built on top of a 200mm, C40 base, reinforced with 2 layers of A393 mesh with starter bars (10mm I think) coming up from the base behind the wall and A393 mesh fixed to these in the void. The mesh is chemifixed into block-built steps at either end of the wall and the wall is fixed at both ends using starter bars and fixed every course.
The wall was built in the summer and the area of the void is just under 3.4m3.
3.4m3 is rather a lot to be lugging around the back of the house, mixing in a drum mixed and then lifting and pouring into the void. It is doable but would be around 200 bags in total and would take most of the weekend with me an a helper or 2. Bulk wouldn't be much use as there are too many steps to traverse with a barrow so would need to be hand-balled.
Can I pump it in, will the wall take it? If not what about if I dropped it to 4 courses (2.25m3) and then do the last m3 by hand?
If both of these options are a no go, how could I go about strengthening the wall to take the pressure? I could get curing accelerators put in the pumped mix so that it would only take an hour or so to go hard.
Regards
Phil
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Comments
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Could you
Semi dry mix or wet layers over time with reinforcing.If unsure wall will take it. Its the weight of the water thats the issue.
mike3.55kw 2 systems 2.3 se 1.25 sw installed may 2011 and oct 2011..
I have never been mis sold anything but i have bought a few things i didnt need!0 -
My choices are pumped (in 1 or 3/4 and topped up by hand) or mixed on site. Just wanted any opinions as to whether a cured wall would take that weight/pressure for an hour or so.
If not how is best to reinforce it?
18mm OSB with a 4x2 frame and 4x2 supports braced against an opposing wall (well, 1 course of block!) as well as the garden beyond the course of block?0 -
A cubic meter of wet concrete weights about 2.5 tonne (2500 Kgs)3.55kw 2 systems 2.3 se 1.25 sw installed may 2011 and oct 2011..
I have never been mis sold anything but i have bought a few things i didnt need!0 -
Cheers...how much would a wall like I describe hold back?
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Ha ha your guess as good as mine! brick/ block holed frogged what mix of mortar when wall built. Its already angled back!!!width of void. Too many variables. I would like to help you out and guess but.3.55kw 2 systems 2.3 se 1.25 sw installed may 2011 and oct 2011..
I have never been mis sold anything but i have bought a few things i didnt need!0 -
don't forget you need drainage through a retaining wall to stop water building up behind it.0
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don't forget you need drainage through a retaining wall to stop water building up behind it.
No you dont.
Drainage needs to be considered as part of the who project, not just one element.
My extension has a cellar with 3 retaining walls...there are no holes in the wall (these would actually create a weakness in a reinforced wall). Instead it is has a land drain fitted and is backfilled with clean 40 or 50mm stone, encased in geotextile!
My retaining wall is holding back another wall that has had the footings exposed...by quite a bit! The current wall has drainage but this is redundant as on top of this is a skim of concrete which in turn is topped with a mix of patio slabs (which were there when I moved in) and concrete (which was done to fill in the gaps made up of broken patio slabs). On top of this is a large deck with a fall away from my house and over this current wall. If any water gets into the ground behind this wall it will be negligible!0 -
Ha ha your guess as good as mine! brick/ block holed frogged what mix of mortar when wall built. Its already angled back!!!width of void. Too many variables. I would like to help you out and guess but.
7nm Blocks and built with a regular mortar mix by a VERY good brickie. The wall is in front of another wall. This wall is is not parallel to the house whereas the new wall is. That way, the wall, my decking and my future pond will all be parallel to my house.0 -
Just bumping this in case anyone has any advice.0
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