Hello,
Today we have a small ledge that looks like this:
http://i.imgur.com/58OvfKa.jpg
Our plan is to repair the ledge with primer and concrete and of course sand it clean. But then we have a section where this ledge is missing, and the question is how to cast such a ledge? I assume you don't manually lay concrete on the stones but need to build some kind of mold where you pour concrete in a more liquid form?
In this case, it is about maybe 2 meters.
Worth mentioning is that we will then build up with a low wall (mexi) on 3 levels on this ledge.
Today we have a small ledge that looks like this:
http://i.imgur.com/58OvfKa.jpg
Our plan is to repair the ledge with primer and concrete and of course sand it clean. But then we have a section where this ledge is missing, and the question is how to cast such a ledge? I assume you don't manually lay concrete on the stones but need to build some kind of mold where you pour concrete in a more liquid form?
In this case, it is about maybe 2 meters.
Worth mentioning is that we will then build up with a low wall (mexi) on 3 levels on this ledge.
Ah, that's probably true, in this case, we're thinking it should only be 3 bricks high, so in this case about 6x3 = 18-20 cm high wall. From what I understand from this instruction: http://www.finja.se/App_Resource/Page/file/tips_ideer/4019-tradgardsmur.pdf it seems like it doesn't require much casting except that 2 layers of the wall should be below ground level.
So maybe it's better to rent a machine to break up what's there today and then dig down 2 levels, i.e., a total of 5 levels of bricks (6x5 = 30 cm)?
What would be best? And what would be the least work? I suspect it's not particularly difficult to break up what's there today with the right machine?
So maybe it's better to rent a machine to break up what's there today and then dig down 2 levels, i.e., a total of 5 levels of bricks (6x5 = 30 cm)?
What would be best? And what would be the least work? I suspect it's not particularly difficult to break up what's there today with the right machine?
attach two wooden boards (preferably with a smooth surface) or two planks. Either with screws or with clamps against the whole part of the heel, seal with a bit of silicon or similar if there are any large holes where the concrete can leak out. Against the ground, you can probably seal with a bit of gravel only.
You can mix the concrete quite dry when casting, so it won't be too sensitive.
If it's sunny and warm afterward, water the concrete well and/or cover it with a tarp/wet towels so it doesn't dry too fast.
Keep in mind that the repair and the existing heel will probably not have the same color as before.
Also, consider "anchoring" the existing heel with the cast one; apart from priming properly, you can place some solid STAINLESS screws, halfway screwed in with a bit of wire or similar between in the existing heel, which will then be embedded.
Edit: Didn't see Stefan's response that came first. I'm not getting into whether it's stable enough to build 3-4 compartments on top of this, it's beyond my expertise.
You can mix the concrete quite dry when casting, so it won't be too sensitive.
If it's sunny and warm afterward, water the concrete well and/or cover it with a tarp/wet towels so it doesn't dry too fast.
Keep in mind that the repair and the existing heel will probably not have the same color as before.
Also, consider "anchoring" the existing heel with the cast one; apart from priming properly, you can place some solid STAINLESS screws, halfway screwed in with a bit of wire or similar between in the existing heel, which will then be embedded.
Edit: Didn't see Stefan's response that came first. I'm not getting into whether it's stable enough to build 3-4 compartments on top of this, it's beyond my expertise.
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Doubtful if it can handle it (if you can handle it) if it had been a cast wall that's been around for a while unless it's really shabby. Sometimes it sticks like hell, sometimes not so bad. It took me 1h to hack up 20cm of old wall that was 40cm wide and 40cm deep with a Hilti that we rented at Cramo to drill a 70cm deep hole @ 20cm diameter in the foundation. But if it's like Stefan says, just concrete hollow blocks that are mortared together, you might manage it with just a sledgehammer if you're lucky.
Not worse than going out and trying a little piece, right?
Not worse than going out and trying a little piece, right?
We have more or less decided to use the existing foundation and instead clean and repair it. Since it has managed to hold the fence for 47 years without any issues, it should certainly support a 20 cm glued wall.
The question remains, however, how we should cast a similar foundation here:
http://i.imgur.com/vqp83cm.jpg
I have received the following tips:
1. Dig down about 20 cm up to the asphalt.
2. Build a form with planks the same size as the existing foundation. Toward the road, place only a plank on top of the asphalt. Soil and asphalt below ground level should be sufficient as the form. Cover cavities with silicone.
4. Pour 4-5 cm of solid concrete at the bottom, make sure no air bubbles remain, let it dry for 1 day.
5. Fill in with lekablock or hollow blocks in the middle of the new foundation, glue if necessary.
6. Fill up with firm concrete to cover the blocks plus a few extra cm.
7. Ensure the surface is even and smooth.
8. Let dry for a couple of days and water frequently.
9. Remove the form, fill the hole back in with soil, no macadam should be required.
After that, you can glue the wall.
Does that sound like a good process?
The question remains, however, how we should cast a similar foundation here:
http://i.imgur.com/vqp83cm.jpg
I have received the following tips:
1. Dig down about 20 cm up to the asphalt.
2. Build a form with planks the same size as the existing foundation. Toward the road, place only a plank on top of the asphalt. Soil and asphalt below ground level should be sufficient as the form. Cover cavities with silicone.
4. Pour 4-5 cm of solid concrete at the bottom, make sure no air bubbles remain, let it dry for 1 day.
5. Fill in with lekablock or hollow blocks in the middle of the new foundation, glue if necessary.
6. Fill up with firm concrete to cover the blocks plus a few extra cm.
7. Ensure the surface is even and smooth.
8. Let dry for a couple of days and water frequently.
9. Remove the form, fill the hole back in with soil, no macadam should be required.
After that, you can glue the wall.
Does that sound like a good process?
Okay, now we have moved the hedge that was there and we see that the previous owners haven't removed the entire footing and there's a part left, which seems to go quite deep. This is what it looks like now:
http://i.imgur.com/JU40J0R.jpg
I haven't reached down to where the footing starts but it is at least 30 cm below ground level
http://i.imgur.com/6ZPskIj.jpg
http://i.imgur.com/8tlTHbg.jpg
At first I thought "more work" BUT maybe it's not? Maybe it's enough if I just put some stainless steel screws or reinforcement bars in the existing foundation and then I just cast the part that's above ground? Could it be that simple? Or do I have to tackle breaking up the whole thing?
http://i.imgur.com/JU40J0R.jpg
I haven't reached down to where the footing starts but it is at least 30 cm below ground level
http://i.imgur.com/6ZPskIj.jpg
http://i.imgur.com/8tlTHbg.jpg
At first I thought "more work" BUT maybe it's not? Maybe it's enough if I just put some stainless steel screws or reinforcement bars in the existing foundation and then I just cast the part that's above ground? Could it be that simple? Or do I have to tackle breaking up the whole thing?
Apparently, the foundation can be used, it actually looks like those who made it initially cast it in two stages. First, one where they just cast with the ground as a mold and then one where they likely built up a mold, added some hollow blocks, and then cast it.
We have now dug out the pit so it is ready for the hedge. Have also cleaned the ledge:
http://i.imgur.com/S55FtW5.jpg
http://i.imgur.com/WqzEcfw.jpg
http://i.imgur.com/RmGuyAq.jpg
http://i.imgur.com/sNccA9K.jpg
The next step is to try to make a mold ((LxWxH) 229x20x7.5.)
1. Do you build the mold on site or on the side and lift it into place later?
2. Which concrete should be used?
3. How do you seal it so that the concrete doesn't spill out everywhere, as there will be quite a bit of leakage?
We have now dug out the pit so it is ready for the hedge. Have also cleaned the ledge:
http://i.imgur.com/S55FtW5.jpg
http://i.imgur.com/WqzEcfw.jpg
http://i.imgur.com/RmGuyAq.jpg
http://i.imgur.com/sNccA9K.jpg
The next step is to try to make a mold ((LxWxH) 229x20x7.5.)
1. Do you build the mold on site or on the side and lift it into place later?
2. Which concrete should be used?
3. How do you seal it so that the concrete doesn't spill out everywhere, as there will be quite a bit of leakage?
Build it on-site and fill around with gravel so it stands where you want. It also seals to prevent concrete from leaking through gaps. Use, or make your own form ties with wire, so the form doesn't slip apart. Once you start pouring, there are small chances to correct a form that doesn't work as intended...
Remove the form after a day, and you can easily remove unwanted concrete flash with a hammer chisel carefully or an angle grinder with a diamond blade.
Use fine concrete.
Remove the form after a day, and you can easily remove unwanted concrete flash with a hammer chisel carefully or an angle grinder with a diamond blade.
Use fine concrete.
I have now tried to build the form but don't understand how to get it straight, this is how it looks so far:
http://i.imgur.com/wozNAOG.jpg
http://i.imgur.com/Gcxa43G.jpg
http://i.imgur.com/mpPGi7D.jpg
So I started by sawing the two long sides, after that I sawed 6 supports with a length of 60 cm. These were driven down as close to the foundation wall as possible, but since it's not cast in form from the beginning, it's very uneven and this means the supports aren't straight. To compensate for that, I tried to make small blocks but soon realized that they won't hold, even if the block supports the long side at the top, it will be tilted out at the bottom where there is no block. Sawing a block with a perfect angle is more or less impossible. Furthermore, the supports aren't rock solid; sure, they stand there but if you put some weight on each one, they move a bit (they're in clay and go down maybe 30 cm in it (really hard to drive them down).
As you can see, I'm using form boards that are apparently particleboard, which also makes them not very stable.
So how do I get this straight? Do I perhaps need to make it in the garage with solid edges that keep it upright in some way?
http://i.imgur.com/wozNAOG.jpg
http://i.imgur.com/Gcxa43G.jpg
http://i.imgur.com/mpPGi7D.jpg
So I started by sawing the two long sides, after that I sawed 6 supports with a length of 60 cm. These were driven down as close to the foundation wall as possible, but since it's not cast in form from the beginning, it's very uneven and this means the supports aren't straight. To compensate for that, I tried to make small blocks but soon realized that they won't hold, even if the block supports the long side at the top, it will be tilted out at the bottom where there is no block. Sawing a block with a perfect angle is more or less impossible. Furthermore, the supports aren't rock solid; sure, they stand there but if you put some weight on each one, they move a bit (they're in clay and go down maybe 30 cm in it (really hard to drive them down).
As you can see, I'm using form boards that are apparently particleboard, which also makes them not very stable.
So how do I get this straight? Do I perhaps need to make it in the garage with solid edges that keep it upright in some way?
Particle board is not the best choice for a mold as its resistance to moisture is non-existent. A rain shower on it and it's done for 
. Ideally, brace the mold with longitudinal beams 45x95, one at the top and one at the bottom, then you won't need as many supports in the ground.
You can also construct these supports a bit differently to make it easier to get the mold straight. Google some images and you'll see
. Ideally, brace the mold with longitudinal beams 45x95, one at the top and one at the bottom, then you won't need as many supports in the ground. You can also construct these supports a bit differently to make it easier to get the mold straight. Google some images and you'll see
Yes, I was also a bit puzzled when I saw that the formply was particle board, but I assume it has been treated to withstand water. It has at least 2 glossy surfaces, and it looks like they've mixed something green into the particles.
I will construct the form separately and reinforce it with battens or similar. I will probably have to place a batten straight over. There's a bit of a space issue where the form is supposed to be, so a longitudinal batten at the bottom end of the plank against the pit will be difficult unfortunately.
I will construct the form separately and reinforce it with battens or similar. I will probably have to place a batten straight over. There's a bit of a space issue where the form is supposed to be, so a longitudinal batten at the bottom end of the plank against the pit will be difficult unfortunately.
Thanks, I've reinforced it and got it somewhat squared. I've also replaced one of the sideboards as it didn't reach as far down as needed. It now goes a bit below the asphalt.
I actually don't think it needs to be anchored in the ground any lower as it weighs quite a bit and existing stones hold it in place sideways.
http://i.imgur.com/GKOBrCU.jpg
http://i.imgur.com/qgSdUI5.jpg
http://i.imgur.com/if00tki.jpg
http://i.imgur.com/6kFmlkN.jpg
http://i.imgur.com/cwHp5fh.jpg
http://i.imgur.com/ZGq3afq.jpg
All that remains is to level it out then it can be cast.
Looking at the weather forecast, it shouldn't be as sunny as yesterday but rather dark clouds. From what I understand, it's not a problem as long as it doesn't pour rain? Tomorrow, however, they're saying it will rain but by then it should be safe, right?
If nothing else, maybe you can put some plastic over it?
I actually don't think it needs to be anchored in the ground any lower as it weighs quite a bit and existing stones hold it in place sideways.
http://i.imgur.com/GKOBrCU.jpg
http://i.imgur.com/qgSdUI5.jpg
http://i.imgur.com/if00tki.jpg
http://i.imgur.com/6kFmlkN.jpg
http://i.imgur.com/cwHp5fh.jpg
http://i.imgur.com/ZGq3afq.jpg
All that remains is to level it out then it can be cast.
Looking at the weather forecast, it shouldn't be as sunny as yesterday but rather dark clouds. From what I understand, it's not a problem as long as it doesn't pour rain? Tomorrow, however, they're saying it will rain but by then it should be safe, right?
If nothing else, maybe you can put some plastic over it?
Now it's looking like something .
Don't forget reinforcement, dowel into concrete blocks and tie against some longitudinal 12mm rebar.
It's much better to cast in rain than in bright sunshine.
Don't forget to fill up against the form to seal against the old wall. Use form ties (you can easily make your own with some steel wire across the form) instead of boards over the form so it's easier to screed off.
Good luck!
.Don't forget reinforcement, dowel into concrete blocks and tie against some longitudinal 12mm rebar.
It's much better to cast in rain than in bright sunshine.
Don't forget to fill up against the form to seal against the old wall. Use form ties (you can easily make your own with some steel wire across the form) instead of boards over the form so it's easier to screed off.
Good luck!