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PostPosted: Mon Apr 23, 2012 1:11 pm 
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Bluey wrote:
In regards making the process more efficient, over time I ended up mixing smaller batches than when I started as I found it quicker and less prone to dying out. I went from mixing half a wall panel worth just in a pile on the ground down to just enough to match one cement bag worth (about 1/7th of a panel) in the mixing bay.


Yeah, I think biting off 1.2m3 of mix in one batch was too much to chew up front, and I'll probably halve that at least for the next run. I'm expecting to have one or two helpers when I ram the walls for-real, so any smaller than that and the ramming will go faster than the mixing.

You used 7 bags of cement per wall panel? That's interesting - I used 14 all told I think, and that was only to 2100 high (although mine was 2000x400 in section so that probably accounts for some of the difference).

Bluey wrote:
Having the mixing bay sped things up as it was all done from one direction and mixing in smaller amounts ended up saving time overall and was more consistent. Maybe something you can try?


If I was building more than 4 more panels I'd definitely consider building a mixing bay, but for the amount I'm going to construct I'm not sure it's worth the time invested. And although I'm mixing on the ground, the risk of contaminating the mix is basically nil since the site here is cut below the topsoil down to the stuff I'm mixing with anyway. I found the worst problem was that the bobcat bucket compressed the mix at the bottom, and by the second or third batch I occasionally broke off a lump of this solid mix and introduced it into the batch. This turned out to be a minor problem since I was spreading the mix in the forms by hand, and could either remove or break up any too-large lumps before ramming.

Bluey wrote:
It also sounds as though you are much more thorough with your ramming. Undoubtably this will produce a more solid wall. I usually made 3 passes over each layer, bouncing the rammer along so each stroke just overlapped the last (as you described). My layers ended up around 100-120mm thick (more like the top half of the lower panel in your close-up pic. Obviously the thinner the layers, the more you need to do and the longer it takes (though the more guaranteed they will be fully compacted).


Funny that - having never done this before I started out with layers too thin, and rammed them well past the point of maximum compression. Because I was moving very slowly across the surface at this point, I was kicking up already compacted mix and then trying to ram it back down again which was basically a waste of time. The first few layers ended up around 50mm rammed, but after that I (accidentally at first) poured more mix into the forms and it rammed down just as well, so I ended up ramming around 150-200mm loose for a 100-150mm rammed layer.

Bluey wrote:
If it is any consolation, I rapidly increased the speed with which I could produce a wall as time went on.


Yeah, I can see that - once my ramming technique improved and I got the layers a decent thickness my speed improved too. I still think it'd be a push to ram a whole 2.0x2.5x0.4 panel in one day (especially with reo mesh, I'm definitely not looking forward to that) but I'll give it a shot!

Bluey wrote:
I'm sorry if my thread gave you and Homeless the impression that rammed earth is easier or quicker than it really is. I suppose a few words and pics of the finished result don't tell the full story. In the end I hope that you will agree that if nothing else, it is an incredibly satisfying process (maybe you need to wait for the pain to subside to realise this :wink: ).


Hehehehe.. yes, it's true, you do make it look easy :lol: But this whole project is an exercise in discovering how badly I can underestimate jobs ;) I'm not afraid of hard work though, and although I might wonder at times what I've started it's just a matter of time before I get it finished. The reward definitely comes at the end though :D

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The adventures of an owner-builder in the Tallarook Ranges


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PostPosted: Wed Apr 25, 2012 9:32 pm 
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I made an ANZAC Day visit to the site today in order to strip the formwork off the wall, since having had rather a lot of rain over the past couple of days I expected the top of the wall to be a small swimming pool. Thankfully my makeshift protection did a half-reasonable job and there was just a small puddle, and the Plasticure seems to work really well preventing the water from seeping into the earth itself.

This is what greeted me this afternoon - cold, wet and muddy...

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Stripping the form panels solo was an exercise in careful thought, since they're bolted together and support each other. It took about an hour in the wet mud to get all four panels off the wall, but no owner builders, small children or dogs were harmed in the process which is an important achievement :)

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Once the panels were off I was able to survey the damage. Not surprisingly, there are a couple of problems with the result:

1. Where the form panels joined (or more accurately, didn't) there is quite a step in the earth which matches the misalignment of the panels. This is quite a sharp step which is fairly easily crumbled away leaving a flaw in the surface finish. The lesson: make sure all formwork joints line up perfectly, and cannot move during ramming.

2. The dry joint as a result of the Saturday evening stoppage is easily visible at around the 1.3m high mark all around the wall. Although given its immense mass I doubt this would cause the wall to spontaneously fail, I'm sure that if I was to give the top part of the wall a decent shove with the bobcat, it would break off. The lesson: be more organised, and don't start a wall panel unless it can be finished the same day.

That said, I'm very happy with the result as an exercise in learning.

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The columns seem to have worked brilliantly - the ends of the wall are perfectly vertical and straight, and the columns don't appear to have moved at all during the ramming. Where the chamfers are screwed to the columns has resulted in a beautiful finish in the rammed earth - a perfectly straight, perfectly formed fillet in the wall and I couldn't be happier with this part of the result.

Another big win is the colouring of the wall. Although there's a bit of temporary black staining from the virgin formwork (this is conspicuously absent from the pine chamfering) I'm thrilled with the colour of the result. I was quite worried that the wall would be too dull given the colour of the sand, but the strength of colour in the local soil (and the off-white vs GP cement) has won through to produce a beautiful warm, sandy finish. The ultimate colour will be a bit lighter than it is at the moment, since the wall is still drying.

I love the appearance of the stratification from the ramming layers, it gives the wall such character. The captive bracketing holding the columns to the slab also worked brilliantly, another big win.

There will need to be a little judicious patching applied to some areas of the surface around joints which were a bit crumbly, but all in all I'm very happy with the test. It's served to prove that I'm able to use a blend of the on-site soil for ramming, and that my methods are sane and the process is within my range of ability.

I think I'll take a weekend off building to give the trusty Hilux some tender loving cash in the form of a timing belt change and brake overhaul, then get stuck into the ramming for real the weekend after when the weather improves :)

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PostPosted: Thu Apr 26, 2012 9:42 pm 
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Nice work, Simon. Looks great! Those chamfers are really neat.

I had the same black staining from a couple of my formwork sheets. Thankfully most of my formwork had already been used for concrete so it was only on the odd sheet. Hopefully yours sorts itself out as I haven't found any way to remove the black stains without damaging the wall surface.

I recommend, if you can, try to trim the top of the walls as soon as you can. Once they harden up it is a pain to trim them back (really dusty grinding or a lot of chiselling required). If your formwork matched the top height of the wall you can just overfill and scrape back with a steel edge while it is fresh. If the formwork goes higher you can cut a piece of 4x2 to the length of the wall between chamfers and once you have slightly overfilled the form, lay the timber on edge inside the form against the ply and hit it down with a small sledge hammer, checking regularly with a spirit level until the outer edge of the wall is packed down to the right height. Repeat this on the other side. The top of the wall will then have a raised section down the middle that you can scrape back with a spade. This will create a nice sharp top edge if you need it.

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PostPosted: Tue May 15, 2012 10:15 am 
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Rammed my first real wall panel this past weekend. All went well in the morning, then after lunch the wheels fell off.

- One of the centre clamping bolts came undone and I didn't notice until the form had bulged out by about 10mm total. Managed to claw some of that back by scraping out the rammed surface and retightening, just enough to get the next form above to line up.

- My compressor seized hard, about two thirds through the panel. I still don't know what its issue was, but after allowing it to cool it would run again for a short time and then lock up again. Dragging it out of the shipping container into the cold outdoors saw it run long enough to finish the wall at 9pm by the light of a long-suffering Hilux.

The full story and pics are here as usual ;)

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PostPosted: Tue May 15, 2012 5:26 pm 
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Location: Blue Mountains
Simon,

I am feeling your pain. Thankfully your day (and night) seemed to work out in the end.

I had a look at your mixing video and I tend to use the opening bucket much more than you when mixing. I generally take a big scoop and then raise the bucket while opening it so the mix falls out the bottom of the bucket, back onto the pile. I think this creates more of a mix than just scooping it up and rolling it back out the front of the bucket. I vary between the two. I also tip the bucket forward as it opens otherwise some of the mix gets trapped in the bottom of the bucket. Dropping the mix from a little bit of height also helps break up clumps. Every so often I drop the bucket on top of the pile and drag it back to squash lumps then I half open the bucket, tip it forward and bulldoze this back into the pile. When I was doing it on the ground I came at the pile from different directions as well. When mixing from one side only you need to be careful that the cement is evenly spread across the pile as the mixing only happens front to back not left to right.

Unfortunately I do not have a video to show what I did.

I agree that there is something special about revealing the wall. It is like unwrapping a present. You never quite know what you are going to get and usually it is a nice suprise. Thankfully this feeling has lasted for me right up until the last wall panel. It certainly helps to keep you motivated.

Keep at it,
Bluey


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PostPosted: Tue May 15, 2012 7:54 pm 
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Bluey wrote:
Simon,

I am feeling your pain. Thankfully your day (and night) seemed to work out in the end.



It did, thanks to the help of friendly neighbours :) I would have been able to finish it myself, but I would have been there until midnight...

Bluey wrote:
I had a look at your mixing video and I tend to use the opening bucket much more than you when mixing.


Yeah, I've tried that but I find that I have less control over what I pick up when I open the bucket and grab the mix from the top. When you're mixing on a concrete slab that's probably not an issue, but as I'm mixing on the ground (admittedly the same material as is going into the mix, just not screened) I find I tend to add lumps when I try that. I definitely get a well mixed batch (approached from all sides as you mention) it just takes a while.

Bluey wrote:
I agree that there is something special about revealing the wall. It is like unwrapping a present. You never quite know what you are going to get and usually it is a nice suprise.


That's it exactly! It's such a beautiful thing, I can't help but touch and admire it. In truth, that's why I'm taking so long to finish a panel - I spend too long admiring the partially-finished product :lol:

I reckon I'll give the next panel a crack this coming weekend since the weather forecast seems to be favourable. Gotta make the most of the dry days!

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PostPosted: Mon May 21, 2012 2:14 pm 
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Got my next wall panel rammed this weekend, and it's a beauty 8) I'm getting better at it with each one, and aside from the tiger stripes from the staining which I'd prefer to avoid I'm thrilled with the result.

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The second batch of mix was slightly too wet, which has left the surface looking and feeling a little waxy straight off the forms, but I reckon that as it dries it'll improve. Either way I could hit it with a wire brush..

This panel (and the last one for that matter) are pretty damn straight, certainly straight enough that you can only really pick the imperfections with a straight edge. It's incredible the power of the little pneumatic rammer, how it causes the stiffest form panels to bow a little even over a short distance :o

The columns are working absolutely brilliantly - the ends of the walls are about as perfect as I could hope to make them. Aside from a little tear-out where the tongue timber forms a rebate for the next panel, they're awesome 8) Bluey - you deserve credit here, they're basically your design and a bloody good one it is, too. The captive bracket holding the forms to the slab is also working perfectly. Even with all the ramming and vibrations, nothing moves even a millimetre.

All that said, this is my favourite bit of the most recent panel:

Image

This is the rebate for the steel lintel which will support the infill above the doorway. This was formed by the block of Kauri pine I cut into two triangles bolted together, and it has worked unbelievably well. I'm stunned how crisp the corners are, it's a beautiful thing to see. It's just a crying shame that they'll never be seen once the door infill is rammed :cry:

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PostPosted: Mon May 21, 2012 9:58 pm 
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Simon,

That wall panel is stunning! 8) I am so pleased (and relieved) that they are working out how you wanted them to. I assume that the tiger stripes will tame down a bit when it dries. If not they tell a pretty honest story of how the wall is constructed.

I am glad that you have managed to squeeze it in around the rain.
Bluey


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PostPosted: Mon May 21, 2012 10:34 pm 
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Bluey wrote:
the tiger stripes ... tell a pretty honest story of how the wall is constructed.

I am glad that you have managed to squeeze it in around the rain.
Bluey


Yeah, I think I've come to accept them as part of the personality of the building :lol: I think if I'd been wire brushing the wall surface once the forms are removed then I'd likely remove most of it, but I can't bring myself to do it. I may experiment with one of the surfaces which will be covered by the infill panel, just to see what effect a little attention has on it.

We've been pretty lucky with the rain - what we have had has happened during the week when I'm not there, and there have been only the one or two very light showers on the job. Mostly we've been getting low cloud (well, low for our 600m elevation ;) ) rolling through which mists everything up. That sort of humidity makes for an impressive show of ice on the rammer though - I really, really must invest in a filter/dryer for the compressor.

It's getting coooold, though.. subzero overnight temps to only low teens during the day :o

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PostPosted: Tue May 22, 2012 7:09 am 
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Nice job Simon. It only seems to be raining out our way when I'm on site :) At least the farmers smile when they see I'm on the block.


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PostPosted: Mon Jun 04, 2012 8:15 pm 
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After missing one weekend due to torrential rain, I got back into it this weekend past and got another wall panel done.

I've been at this wall for a month now.. how are you blokes getting this done so fast!? I'm taking two days per panel (setup on day 1, ramming on day 2) and it's taking everything I've got to get it done in this amount of time. If I was building the whole house this way, it'd take years!

Pics!

Just about to start ramming, 7:45am Saturday:
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The last of the first batch of soil all rammed:
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Nearing the top, with two hours of daylight remaining:
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The result at 8pm in the dark and the cold...
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I'm getting better at the panels after each one, but pretty much everything went to plan today and it still took me 12 hours to produce this one. I really don't think I could do it any quicker.. it's taking everything out of me to get them done in this time. Bluey and Homeless, I have massive respect for your efforts - if I were building my entire house in rammed earth it'd take me years, but you guys are getting it done and doing a brilliant job.

Image

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PostPosted: Tue Jun 05, 2012 7:33 pm 
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Once again great work. I read in your blog that you had to rebuild the end column. I think that the effort was worth it.

In regards the amount of time it is taking you, I think that you are being a bit hard on yourself. I could only manage a panel every 2 days and my panels were almost half the volume of yours. Your largest is around 2.1 cubic metres and my largest 1.13 cubic metres. You also have the added challenge of reo mesh in the middle. I once tried to do 2 panels on consecutive days and I was a wreck (and that was with a night sleep in between). I also have the advantage of a very flexible job so I am not confined to weekends only which makes things happen a lot quicker when need be.

Bluey.


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PostPosted: Tue Jun 05, 2012 9:17 pm 
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Bluey wrote:
Once again great work. I read in your blog that you had to rebuild the end column. I think that the effort was worth it.


Thanks Bluey! Yeah, I wasn't happy with the quality of the surface in that one column and there was no way I'd be able to patch it up to a standard I'd be happy with, so it was just easier to replace the form ply and chamfer timbers. I'm very glad I did, because this end is the best one yet and it will be the most visible so it's a good result.

Bluey wrote:
In regards the amount of time it is taking you, I think that you are being a bit hard on yourself. I could only manage a panel every 2 days and my panels were almost half the volume of yours.


Heh.. you're probably right. It's easy to lose sense of the time it has taken you to build yours, since I'm just reading about it after the fact and not as it's happening. I guess I'm just dissatisfied with being only able to produce one panel per week, but I'm not about to try to build two on consecutive days! One panel takes so much effort not just in the ramming but in setup too, and I'm utterly spent after each one.

Bluey wrote:
Your largest is around 2.1 cubic metres and my largest 1.13 cubic metres. You also have the added challenge of reo mesh in the middle.


Wow, I hadn't realised my panels were that much larger than yours! That puts it into clearer perspective, but quite honestly the reo mesh doesn't impose much of a penalty at all. If anything, since it (and the centre bolts) force me to ram the earth in quadrants it's actually helping my speed because I spend less time going back over sections which I've already rammed. I find that when ramming each quadrant I "spill" mix through the mesh as I move through the loose stuff, and if I had easy access to it I'd want to go back and ram it down unnecessarily. As it is, that spill just gets rammed with the next layer.

Out of interest, what sort of ramming head do you have on your rammer? I've been trying to understand what has caused the tiger stripes in my walls, and I've come to the conclusion that it's a thin film of rubber which is being left on the form ply by the ramming head. Two things lead me to this:

1. The stripes fade towards the bottom of each layer, where the ramming head has little opportunity to strike the formwork.
2. It seems that any colour on the forms is very, very easily transferred to the earth. I've marked my final height on the pine chamfers with permanent red texta, and in this last panel where I've gone over this height slightly I've found that the earth has a very clear red line ;)
3. For some reason the ramming head isn't leaving anything behind on the pine chamfers - once or twice I'll leave a skid mark if I hit it hard enough, but generally the pine stays clean and the earth there is unstained.

I think when I build my next rammed earth structure (yes, there will be another - I'm addicted :lol:) I'll build the forms using CD or DD grade plywood (perhaps clad over the form ply). The earth takes such a perfect negative image of the forms that I think it'd look pretty cool 8)

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PostPosted: Wed Jun 06, 2012 5:42 pm 
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Simon,
The head on my rammer is stainless steel so you might be onto something with your thoughts about the rubber marking the formwork. The couple of times I had black staining on the walls was from the newer formwork. The black did not appear as tiger strips but more a general darkening that matched the formwork panel. Once the forms had been used they stopped causing the stain.

Your idea of using heavily featured ply sheets should create an interesting effect.
Bluey.


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PostPosted: Wed Jun 06, 2012 8:09 pm 
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Bluey wrote:
The head on my rammer is stainless steel so you might be onto something


Ah, I reckon that's it then! I've still not attacked any of the wall surfaces with a brush, but I suspect if I do that then I'll lose some (or all, who knows) of the staining. It's starting to grow on me, so I'm not sure that I want to be rid of it now :lol:

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