Build Your Own House

Bugger.

I had the concrete and pump booked today to fill the retaining wall, but the pump operator pulled out at the last minute citing problems with the pump. I actually think he didn't want to bring the truck up the mountain in damp weather, in case he had trouble getting back out of the house site again. So, no wall filling happened today

Instead I kept myself busy between rain showers by building up the end columns for the rammed earth forms.





The Hilux tray certainly makes a convenient work platform

I'm using second-hand 90x45 F5 pine for the bracing on these, as I have a bundle which I picked up for next to nothing. I've been thinking about the form panels - I had originally intended to use full 1200x2400 form ply sheets to minimise the number of joints which will be visible in the rammed panel, but after putting the columns together I think they'll be too heavy to handle by myself.

So, I think what I'll do tomorrow is cut the sheets down to 2400x600 and use two lengths of 50x50x5 steel angle horizontally as bracing, since I have plenty of that handy and using these will allow me to bolt successive courses of panels together accurately and hopefully minimise the visibility of the joint between them. The smaller sheets should be easier to handle by myself without giving myself a hernia.

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Simon.

The adventures of an owner-builder in the Tallarook Ranges

I feel your pain simon
We have experienced delays due to weather
my observation is that it does seem like an early autumn break
but it will dry up and you will have plenty of beautiful days before winter proper
so keep on the contractors case and have them ready to go
i'm sure there is still time to get a concrete truck in
good thing down here is that it has settled the dust

formwork
tearout
I have some feedback coming

Ah, I'm not too worried about the weather - I'm sure it'll dry out a bit next week and I'll get the wall filled.

I made a bit of useful progress on my formwork today - I have both sets of columns just about complete, and one full side panel completed with all the steel cut for the second. I did however run out of acetylene - I've only just got these bottles so I think they gave me a short fill So that put a halt to the construction this afternoon.





Once assembled, these seem pretty stiff - I am able to stand on the middle of the form with blocks at both ends, and it barely deflects at all with my 80kg weight. Here's hoping they don't deflect much (at all) during ramming - I know they will, it's inevitable, but I can hope

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Simon.

The adventures of an owner-builder in the Tallarook Ranges

Those forms and columns look great Simon. Once again some very tidy work you have there.
Bluey.

Thanks Bluey, you should find the columns somewhat familiar I'm trying to maintain as much precision in the formwork construction as I can, as any error here will show up as flaws in the wall and I'll know they're there...

I'm planning to start ramming my first wall over Easter, but the weather may have something to say about that. It'll take most of next weekend to get the forms complete, and I also have to get the retaining wall core filled so it'll be a busy time

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Simon.

The adventures of an owner-builder in the Tallarook Ranges

I am interested in where are going to position the bolts. It looks like the forms will clamp on to the outside of the column and then I assume the bolts will go through the forms and the column. If so this will be fine for the first couple of walls but where will the bolts go when you want to clamp the forms on to the other wall panels instead of the column. Will they be set in from the join and the holes filled later like I did on my garage?

I've not yet updated the through holes on my drawing of the latest (final!) prototype, but with my 1200 high form panel design I had the holes positioned such that everything lined up either when using the columns, or when clamped against the walls "filling in the gap", so to speak.

I'm hell bent against unnecessary holes in the walls, both to minimise the amount of filling I'll need to do afterwards and to avoid the imperfections visually. There will be one set of holes in the chamfer between wall panels, and that's it. My form panels will be long enough that the clamping rods will pass through the columns and miss the wall entirely on the end wall sections.

Once I get the Sketchup drawings updated I'll post pics of the detail

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Simon.

The adventures of an owner-builder in the Tallarook Ranges

A little more work in Sketchup tonight to detail the type, size and placement of the reo mesh inside the rammed earth walls. As usual I’m glad I’ve done this work, because I’ve picked up (yet again) a couple of little gotcha’s which would have made the earth ramming a little challenging in a couple of places.

Case in point - without having placed the starter bars in the drawing before jumping in and doing them for real, I wouldn’t have realised that they will interfere with the placement of the end column forms. Since I’ll be leaving a gap between panels as I ram them (and filling in the gap without using the columns, bracing against the rammed section of walls), if I installed the starter bars in these gaps then I’d have nowhere to place the column on that side.

Thanks, Sketchup!

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Simon.

The adventures of an owner-builder in the Tallarook Ranges

As promised

I basically have four panels to ram - three are 2000mm long, one is 2100 (and there's also the infill above the door, which is 900 long, making for a 9m wall in total). I'm ramming the wall 400mm wide, for two reasons - firstly, the engineering spec suggests (but does not require) a 400mm base tapering to a 300mm top, but I think it will be much easier ramming the wall parallel. The second reason is that the panels have internal reo mesh, so the additional width will be welcome space during the ramming.

The fact that I have one 2100 long panel complicates the forms a little, but not by much - it means I have one additional set of holes for clamping bolts, but I should be able to blank these with some appropriate sized dowel when I don't need to use them, and hopefully this will prevent the wall being damaged by "plugs" of earth being torn out when the forms are removed.

So this first illustration shows the assembled forms for the 2100 long panel, with reo in place. Each 600 high panel is secured by two bolts on each end, and will be bolted in four places to the panel above when that is placed.



Note that the column which forms the end of the wall has a "plain" surface - with my layout there will be no need to pass bolts through the joint which this column forms, so I can avoid the disruption to the end surface which would be caused by the grooves necessary to allow the bolts to pass through.



After this panel is rammed, the columns are moved to the other side of the doorway to form up the first 2000 long panel. Note that one column will have a block fitted to form a rebate in the earth wall, in order to allow positioning of the lintel prior to ramming the infill above the door. The through bolts miss the wall completely on the doorway side (again, keeping the surface smooth) but pass through the column at the joint between the wall panels at the other end.



And again with ramming in progress.



The columns and forms are then moved to the other end of the wall, leaving a gap which will be filled in last. Note the tapered rebate formed in the wall as a control joint - this will be lined with foam to keep the wall panels physically separate, and allow any expansion or movement without causing cracking. Not that the wall will go anywhere anyway, but it's in the spec.




Then finally, the columns are removed and the form panels clamped against the wall panels. For this panel the through bolts pass through the joint between the panels.




So this is the plan. I aim to get the forms pretty much complete this weekend (in addition to the core filling of the retaining wall.. wish me luck!) and potentially ram another test block using these forms and the actual wall materials over the Easter weekend.

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Simon.

The adventures of an owner-builder in the Tallarook Ranges

Simon,
That system looks great. I really like the idea of going to 400mm as I agree the extra space will be useful.



If the plugs still leave marks, pat them out as soon as you remove the forms rather than trying to patch/scrape them when the wall is hard. I reckon use your test block to experiment with ways to repair damage. I used a thin steel tile trowel that had the edges slightly turned up so they didn't leave marks and smacked any areas I filled with it. A flat piece of wood about 200mmx300mm with one face made slightly curved towards the edges by planing or sanding and a handle on the back I reckon would work just as well.


If that is a rectangular piece of wood, I think you will find it very hard to remove without cracking the remaining bits of wall. Consider making it from a couple of pieces like so:

When viewed from top:

To assemble first screw through the yellow piece into the red:


Then screw through the back of the column into the yellow:


When you are ready to strip the forms take the screws out of the column first, remove the column and then remove the other screws and the yellow piece should come out, followed by the red. I would only attach the block when the rammed earth is up to that level so that it is out of the way and you can compact under it properly (it is supporting a lintel after all).

I would even still put a slight taper on the block as shown by the folowing example dimensions:



The only other suggestion is that if you are planning on just bolting on to the outside of the ply where those couple of holes do not line up with the steel frame of the forms, I would also bolt through a piece of timber that spans from one part of the steel frame to another (I understand that you may be planning something like this but I am only going off the drawing).

All in all, it is looking good to me!
Bluey

It aught to, it's yours



Good tip I have a plasterer's sanding float at home which I'll fettle, I think... should do the job nicely.



I thought that myself when I drew it (I'm suspicious of simple pushed rectangles in Sketchup when it comes to rammed earth ) but that's a work of art, Bluey!! Very clever



To be honest I'd not really thought about it but now that you mention it, without some bracing the form ply is going to want to bow out between the bolts. Perhaps I'll cut up a couple of extra lengths of steel angle for this purpose...

Sincere thanks for the advice Bluey, I really appreciate you taking the time to produce drawings to help me avoid little mistakes. Next time you're in Victoria, the beers are on me

In other news, my core fill this morning went without a hitch. I had a bit of a mad scramble setting up a work platform along the wall before the pump arrived, but got it done and got the cores wetted down nicely before the concrete arrived.



The first shot from the pump was a little dry, but after we added some water to the mixer it flowed beautifully, only needing a little rodding with a rebar offcut to encourage it to the bottom of the wall. We took a 20 minute break after filling the wall half way to allow the first lift to go off a little, then poured the rest.

My fears of blowing out blocks were largely unfounded - we took it slow and the blocks which I thought would cause a problem were fine. I did spot one block towards the top of the wall which had cracked after I laid it (but before we filled it) so I braced that one to make sure it didn't move. It didn't



Easy peasy, I don't know what people are on about when they've told me this is a hard job

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Simon.

The adventures of an owner-builder in the Tallarook Ranges

Nice work on the wall!


With all of your research and preparation, hopefully you will find many things easier than expected.

I just spotted a couple of things with your bracing that might give you grief. You have put a single diagonal brace, offset to one side, on each end of the wall (Just like in the photo of my bracing). That was the first time I set the forms up that way and I found that the top of the column would twist as the forces were restrained on one side only, the unbraced side would still slightly push out. I then changed to putting double braces (like in my sketchup drawings) to prevent this.

I also see that you have packed the cross bracing out away from the column to clear the end of the forms. The ideal would be to have this bracing in line with the end of the wall. The further away from the end of the wall, the more chance the top of the wall will have of moving off line. Could you instead fix the cross piece on top of the column (assuming your forms are not higher than the column) and have 2 pieces on the bottom fixed somehow to the bottom bolt and extending out?

Maybe like this..


Bluey.

Well spotted I'm just lazy, I haven't drawn that in.

There are elements of the build process that I'm pretty confident with, and those I haven't felt the need to test in Sketchup first. These braces are one example - I've drawn a wide longitudinal base prop timber, to which I can attach a brace on both sides to the top of the column. I've already cut the timbers for these, but I never got around to updating the drawing - in Sketchup, it can be a PITA when you adjust one aspect of the drawing and have to completely redo others in response. I often find it easier to put "placeholders" in instead, as reminders that I need to add something else rather than draw it and maybe have to redo it later. These fit into that category



Yeah, I'm not terribly happy with this bit myself but I realised that after I altered the form panels to 600 high, I'll need one final lift for the last 150mm or so of wall and so the panel will foul the bracing. (I chose 600 high panels for two reasons - weight, and the fact that I can get two panels out of one sheet of form ply. In my original drawings I'd arrived at the panel height as an even fraction of the total wall height, but that turns out to be too impractical from a materials point of view. Everything is a compromise ).

Since my final lift will take the panels above the top of the columns, I can't extend bracing perpendicular to the wall within the length of the form panels - hence I've gone longitudinally. I'll have a fiddle with the drawings during the week and see if I can't arrive at something better.

I should have a decent update this weekend - I'm hoping to get the next set of panels welded up during the week, and the first forms fully assembled on Friday for a Saturday ram I have enough materials (sand and cement; the local earth is abundant) on site for one panel only, but I doubt I'll get any further than that with my first full-scale wall anyway.

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Simon.

The adventures of an owner-builder in the Tallarook Ranges

Well, it's taken quite a bit longer than I had hoped but I'm finally at the point where I can start ramming earth

I have my formwork columns erected, plumbed and braced and I have to say I'm quite happy with how they look and feel. Time will tell tomorrow how well they perform but since they're basically Bluey's design I'm confident there'll be no dramas.

Famous last words



There's one last detail to resolve, which is the perpendicular bracing on the far column. As I lift the panels to full height I'll need to adjust the mounting of these braces to miss the panels, since they're 2300 long in order to accomodate a 2100-long panel (this test wall is 2000 long).

The full story in the build-up to ramming is here - I'm too lazy to retype it here

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Simon.

The adventures of an owner-builder in the Tallarook Ranges

Simon,
Thanks for posting a link to your blog again as I had forgotten to check it for quite a while. The level of detail you go to in documenting your progress makes for interesting reading.

Congratulations on getting your trail wall panel up . I think it was a great idea to make use of it as a radiant heat shield though you must be frustrated by the council inspection process.

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.

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?

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).

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

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 ).

Keep at it,
Bluey