Hi devo, If I've done my conversions correctly those are going to be huge. I am assuming you mean 200cm square for the base? That's about 6 1/2 feet on a side. 1.6 to 1.8M tall is 5-6ft high tapering to 80cm is 2 1/2ft square. Sorry to do that again for you but other readers may not know the size you are talking about.

That size project would seem to me to require a bit of engineering. I'd be careful doing this without some kind of input from a professional. I'd hate to see all your work come tumbling down due to some easily correctable oversight.

My unprofessional opinion is your idea about building a frame seems better than trying to cast, raise and set panels.

I hope someone can give you more concrete ideas as to how to finish this project than I can. I hope you're successful with this. Good luck.

Hi rockhewer...thanks for your reply. Let me just clarify the size issue. In my haste...I did not explain myself very well...

My plan (at this stage)is to have the pillar stand about 1.8m or say 6ft high. Each pillar will have 4 sides, with each side being say 50cm or approx 20inches at the base, tapering up to the top of 20cm or about 8inches. So then on completion, the base will be 4X50cm =200cm or approx 6ft around the whole pillar.

Now, the idea of using 4 X concrete panels came from a water feature I made last year. (photo below) This water feature consisted of 2 waterforms, made with the same mix I would use for tufa, but just left out the peat...and added reinforcing rods. Each waterform has a soild concrete footing, so is very stable. So, my thought process was to use a similar mould, just take out the "S" bend of the waterform mould, and lean the 4 concrete panels together to form a hollow pillar. Letter box can then be added, and a planter incorporated into the top. I can see it working in theory, but in practice....hmmmm...it may be a little more difficult.

Here is a photo of the waterfeature. The 2 waterforms are concrete, with a textured finish. The rear wall is concrete block, with plaster finish. Then a paint effect was applied to give the whole thing an aged...worn...rusting...look.

{{gwi:68579}}

So, just imagine 4 of these, together, (without the "S" bend)forming a square pillar, but having a true tufa finish.

What do you think....??? Am I on the right track....???

Hi devo, Thanks for the clarification. Yes I think that the smaller sized panels may work, especially after seeing your waterform feature you made. That is very nice work. I think you have a great idea there and could be done either way now.

The only thought I have now is what you really want it to look like when finished. Like a single piece of solid stone? The panel method may be a bit harder to finish off to get that type of look and may show cracks along the joint lines in the future after some aging. So I think it may just be a matter of what you'd be happy with.

Hi,
This is my first post, I think. Beautiful work! I'm getting too many ideas!
I can't remember where I found this, but this woman built some obilisks (sp?) that have the shape you want. She built a plywood form, with a removable top. Then, she packed tufa around the perimeter of the open "coffin." She made a conical shape with chicken wire and stuffed that with plastic bags, then used that to fill the void. She packed tufa on top of that, so it was level with the top edge, then secured the top piece to the rest of the form.

Maybe someone can point you to the website. I'm sure I found the link on this forum :) She may have used concrete, but tufa would probably work.

Can you tell us how you made your waterforms? And, everything else in the picture? If I had some lifesize Tonka trucks, I could get a faster start on my yard!

Tammy
Anchorage (zone: whatever)

Thanks for the tips rockhewer....I had not considered the issue of my pillar cracking on the joins....I guess I am going back to the tufa mix over a wooden frame idea.

Good timing on the post Tammy...that plywood form idea could work for me.

Now those waterforms are just a basic concrete mix, poured into a mould to give the shape I wanted. They each have a plastic water pipe inside to allow a little pump to recycle water from a sump hidden under the river stones, up thru' to the top of the forms, where it spils over and runs down the front face. The forms were created to serve as "garden art" (even with no water flowing) and to be a water feature, without the problems associated with an open pond. They do look very nice at night, with a spot light highlighting the movement of water as it slowly runs down the forms. The rest of the garden is just a planting of Bromeliads to add a punch of colour, mondo grass, astelia, & titoki for screening. You would have to alter the planting sytle to suit your situation....Bromeliads like it warm...but the water forms could go in any situation...even a bit of ice would add a nice touch...