This is what I'm trying to do - I'm happy with taking my time, I just want to know I've thought about every stage.
To show how much extra care I've taken, you can find my Excel plan for the brickwork and footings here. Each cell is accounting for 1cm, and I have used the block sizes that you mentioned owd. From my plans, the only thing I haven't accounted for is the extra space for footings around the water feature so I will need to revisit.
The first block size starting from left will run roughly 1500mm in width (inc. all block sizes), the next box will run 450mm in width (exc. wall to left), the centre area for water feature will be 800mm in width, and then the same widths for the two sections to the right.
I planned that the taller blocks would be 3 blocks high, and the smaller blocks (and wall in front of water feature) would be 2 blocks high.
I was going to aim to be around 250mm deeper than the grass, which would give me around 150/200mm of concrete footings.
OK, you have obviously thought about cutting blocks for your design so that's fine. 150mm deep strip footing will be sufficient under the walls, and as others have said, wide enough to sit the blocks centrally. Under the water feature you want to create a sump. If I was doing this I would extend and connect the footings either side to create a continuous bed. Does that make sense? What about power requirements for lights & pumps. Solar or mains?
OK, you have obviously thought about cutting blocks for your design so that's fine. 150mm deep strip footing will be sufficient under the walls, and as others have said, wide enough to sit the blocks centrally. Under the water feature you want to create a sump. If I was doing this I would extend and connect the footings either side to create a continuous bed. Does that make sense? What about power requirements for lights & pumps. Solar or mains?
Great - at least I'm getting somewhere with my planning haha!
I'm not entirely sure what you mean here with the sump. The only reason I haven't extended the bed is due to the water features reservoir box being depth 65cm x width 80cm. For a wall to go behind it, I would then need to bring the entire raised bed out a little bit further (unless im misunderstanding)
My girlfriends brother is an electrician so I was going to leave it to him haha. I want it into the mains tho!
Sump = your water feature reservoir. I was assuming you would also be constructing this as a small concrete pond. Sounds like you are purchasing a ready made sump with the water feature? If so then it probably just needs to be installed onto a sand bed, so you do not need to construct any foundation beneath it and we are back to just the strip footings beneath your walls only. Good. Great that you have an electrician, but you will need to make allowances for incoming supply cabling which will presumably be buried SWA cable. Talk with your electrician to plan entry points within your structure (easier to build voids in rather than drill afterwards etc). Consider the depth that you need to excavate to. This will depend on your design height and your soil as already said, if clay it will shrink and heave with moisture content so can cause later cracking etc. You need to create a solid founding level from which to build, either of compacted earth or, if your soil will not permit this, consider laying down a layer of well compacted hardcore to build your foundations on.
Ahh yes I already have the sump. The water feature is something that I have been given already, so my designs have changed to factor in. I originally didn't plan for the size of the sump (however my latest plans do include it).
The sump box is roughly (depth) 65cm x (width) 80cm x (height) 40cm
I don't believe my soil is clay.
How would you recommend laying the foundations? Could I potentially lay hardcore in the entire trench and compact it with a wacker machine? Or would this cause issues for my raised beds gathering up moisture?
just compact beneath the strip footings on which you will build your walls. I would not bother to lay hardcore beneath your planter areas, just break up the subsoil to assist drainage as others have already said. Use a string line to obtain an accurate alignment and erect your formwork both sides of your footing, I use ply cut to suitable depth of footing and stake every metre or so with 400-500mm lengths of 32x32mm softwood sharpened to drive in easier. Insert stakes to establish the top level of your concrete footing and to which you will tamp the concrete to obtain an accurate finished level. You want this as good and level as possible. Lay your concrete foundation directly on the hardcore and level and compact to your finish level this with a 2.5m length of 75x50mm (or similar) softwood.
just compact beneath the strip footings on which you will build your walls. I would not bother to lay hardcore beneath your planter areas, just break up the subsoil to assist drainage as others have already said. Use a string line to obtain an accurate alignment and erect your formwork both sides of your footing, I use ply cut to suitable depth of footing and stake every metre or so with 400-500mm lengths of 32x32mm softwood sharpened to drive in easier. Insert stakes to establish the top level of your concrete footing and to which you will tamp the concrete to obtain an accurate finished level. You want this as good and level as possible. Lay your concrete foundation directly on the hardcore and level and compact to your finish level this with a 2.5m length of 75x50mm (or similar) softwood.
I'm really appreciating all this help owd!
I have small gravel which I removed from what was originally there. Would that work as hardcore or do I need to get some proper stuff? Also, would you use a Tamper tool rather than hiring a proper wacker machine?
I think I'm understanding but may be wrong. Using my design as a plan:
1) Put stakes (top of stake will be the height of concrete footing) in each corner of my planter areas (5 planter areas inc. the sump)
2) Put an additional stake within my larger planter areas so I can check they're all level
3) Using a level, check all stakes are aligned
4) Put plywood on the outsides of stakes to stop concrete pouring in to planter area
Yes, that’s fine! I personally wouldn't bother with the staking, just nail or even gaffer tape the corners of the bottomless boxes together and brace them with a few bricks on the long sides, if you push the plywood into the soil an inch or two that will be more than and a few bricks will be more than enough to hold in place while the poured concrete sets. Remember its a temporary structure not a major engineering project. Sometimes you just have to get on with it, you are overthinking it and at this rate it will never get done
Don’t forget you need the footings under the walls running from front to back as well, which is why I was suggesting you simplify it into two boxes either side of your water feature, but up to you.
Mountainous Northern Catalunya, Spain. Hot summers, cold winters.
I stopped overthinking and have done all the footings now with some wood
I need to order my blocks but have seen various articles online suggesting different densities. These are what I'm thinking to order - do they look okay to render?
Posts
Thanks Owd!
This is what I'm trying to do - I'm happy with taking my time, I just want to know I've thought about every stage.
To show how much extra care I've taken, you can find my Excel plan for the brickwork and footings here. Each cell is accounting for 1cm, and I have used the block sizes that you mentioned owd. From my plans, the only thing I haven't accounted for is the extra space for footings around the water feature so I will need to revisit.
The first block size starting from left will run roughly 1500mm in width (inc. all block sizes), the next box will run 450mm in width (exc. wall to left), the centre area for water feature will be 800mm in width, and then the same widths for the two sections to the right.
I planned that the taller blocks would be 3 blocks high, and the smaller blocks (and wall in front of water feature) would be 2 blocks high.
I was going to aim to be around 250mm deeper than the grass, which would give me around 150/200mm of concrete footings.
Does this sound alright?
150mm deep strip footing will be sufficient under the walls, and as others have said, wide enough to sit the blocks centrally.
Under the water feature you want to create a sump. If I was doing this I would extend and connect the footings either side to create a continuous bed. Does that make sense?
What about power requirements for lights & pumps. Solar or mains?
Great - at least I'm getting somewhere with my planning haha!
I'm not entirely sure what you mean here with the sump. The only reason I haven't extended the bed is due to the water features reservoir box being depth 65cm x width 80cm. For a wall to go behind it, I would then need to bring the entire raised bed out a little bit further (unless im misunderstanding)
My girlfriends brother is an electrician so I was going to leave it to him haha. I want it into the mains tho!
I was assuming you would also be constructing this as a small concrete pond. Sounds like you are purchasing a ready made sump with the water feature?
If so then it probably just needs to be installed onto a sand bed, so you do not need to construct any foundation beneath it and we are back to just the strip footings beneath your walls only. Good.
Great that you have an electrician, but you will need to make allowances for incoming supply cabling which will presumably be buried SWA cable. Talk with your electrician to plan entry points within your structure (easier to build voids in rather than drill afterwards etc).
Consider the depth that you need to excavate to. This will depend on your design height and your soil as already said, if clay it will shrink and heave with moisture content so can cause later cracking etc. You need to create a solid founding level from which to build, either of compacted earth or, if your soil will not permit this, consider laying down a layer of well compacted hardcore to build your foundations on.
Ahh yes I already have the sump. The water feature is something that I have been given already, so my designs have changed to factor in. I originally didn't plan for the size of the sump (however my latest plans do include it).
The sump box is roughly (depth) 65cm x (width) 80cm x (height) 40cm
I don't believe my soil is clay.
How would you recommend laying the foundations? Could I potentially lay hardcore in the entire trench and compact it with a wacker machine? Or would this cause issues for my raised beds gathering up moisture?
I would not bother to lay hardcore beneath your planter areas, just break up the subsoil to assist drainage as others have already said.
Use a string line to obtain an accurate alignment and erect your formwork both sides of your footing, I use ply cut to suitable depth of footing and stake every metre or so with 400-500mm lengths of 32x32mm softwood sharpened to drive in easier.
Insert stakes to establish the top level of your concrete footing and to which you will tamp the concrete to obtain an accurate finished level. You want this as good and level as possible.
Lay your concrete foundation directly on the hardcore and level and compact to your finish level this with a 2.5m length of 75x50mm (or similar) softwood.
I'm really appreciating all this help owd!
I have small gravel which I removed from what was originally there. Would that work as hardcore or do I need to get some proper stuff? Also, would you use a Tamper tool rather than hiring a proper wacker machine?
I think I'm understanding but may be wrong. Using my design as a plan:
1) Put stakes (top of stake will be the height of concrete footing) in each corner of my planter areas (5 planter areas inc. the sump)
2) Put an additional stake within my larger planter areas so I can check they're all level
3) Using a level, check all stakes are aligned
4) Put plywood on the outsides of stakes to stop concrete pouring in to planter area
5) Lay hardcore in foundations outside planters
6) Tamper hardcore
7) Pour concrete into foundation
Or have I completely missed the boat?
Don’t forget you need the footings under the walls running from front to back as well, which is why I was suggesting you simplify it into two boxes either side of your water feature, but up to you.
I stopped overthinking and have done all the footings now with some wood
I need to order my blocks but have seen various articles online suggesting different densities. These are what I'm thinking to order - do they look okay to render?
https://www.travisperkins.co.uk/concrete-blocks/solid-dense-7-3n-concrete-block-grey-100mm/p/700064