Was this created with formwork?

[kingandy2nd]

Hi all,

Only the builders could say for certain I know, but do you guys think these concrete structures were made with formwork?

http://www.houzz.com/photos/54213/Parks-Residence-contemporary-landscape-san-francisco

We need a small retaining wall in our garden, and I like the idea of something like this with the deck built into it.

Cheers
Andy

 

[noseall]

Casting seamless smooth concrete structures in-situ is a difficult job and requires plenty of skill. Ask Norcon!

It certainly looks like cast in-situ though a closer look would tell more, i.e. if the concrete sections were say small, interlocking and portable.

 

[kingandy2nd]

Hi Noseall,

Many thanks for taking the time to respond.

Yes I’ve seen some of Norcon’s postings and he’s into some serious concreting. Saw one of his threads about a football grandstand which looked huge!

There’s a couple of slightly closer up shots on that website, and I can’t see any evidence of joints.

For my house we’ve got about 200mm of soil to retain so not exactly excessive forces, but there’s about 20m of length to the existing wall (which is a the horrible rock wall pictured below):

View media item 57778
I thought something like in the link might be a nice solution – albeit difficult to achieve.

When the weather gets a bit better I might do an experiment with a run of a few meters and see how it turns out. Worst case I end up with some hardcore for my new shed base

Cheers
Andy

 

[noseall]

Shuttering for concrete is all about preparation, pouring the concrete in is the easy bit!

Don't underestimate the weight of the concrete.

If your shutter forms are wonky or misaligned, then so will be the finished product.

You may need to vibrate/poker the concrete after pouring.

You will likely need steel reinforcement, i.e. rebar etc.

You will require a decent mix of muck with plenty of fat i.e.C35 etc.

 

[kingandy2nd]

Many thanks again for the info, that's really helpful.

I feel a really good project coming on for the summer

 

[dann09]

As above,
great care in the formwork/shuttering, and working the mud and the three finish surfaces. Note the pencil round "corners".

The mix must be a particular specified mix, and the pour arrangements must be agreed in advance.

Often, custom (aluminium?) forms are used, and stripped just in time to work any blemishes in the green concrete.

As a DIY'er it's great that you want to tackle such a job, but it's truly a very professional skill that's required to achieve such a finish.

 

[kingandy2nd]

Very good points dann09 thanks for the input.

I had spotted he rounded corners and wondered about how to achieve this.

I know that I likely won't be able to achieve such a perfect finish, but I fancy giving it a crack and seeing what I can achieve. I'll do a couple of trails of a couple of meters and see where I get to. If it looks awful I'll reconsider.

Nothing ventured...

 

[joe-90]

That's rendered concrete blocks, nothing poured there.

 

[kingandy2nd]

What makes you think that Joe? Looks to me like there is a distinct horizontal line where the different layered heights meet.

Another photo here:

http://www.houzz.com/photos/54212/Parks-Residence-contemporary-landscape-san-francisco

 

[joinerjohn]

That's rendered concrete blocks, nothing poured there.

You sure it wasn't created by God ? (because, it sure as hell didn't evolve there)

 

[Norcon]

It looks like a cast in situ pour to me.
With a little pond like that you could easily suspend the inner shutter and complete the base and dwarf wall in one pour creating a seamless seal.

With little walls up to 300mm tall we would sometimes make "over brackets" in a U shape thus no tie bar holes through the finished cast.

The overall look in that image with the decking and lawn divided with the dwarf wall looks very professional.
Its not sitting at the back of your average semi.

 

[joe-90]

I'll go with what Norcon says - that's his specialty.

 

[kingandy2nd]

.

With little walls up to 300mm tall we would sometimes make "over brackets" in a U shape thus no tie bar holes through the finished cast.
.

Thanks for your input Norcon, I know you're the authority on concrete on here.

I do think it looks like a very professional job.

Could you explain the sentence above for me please as I don't really follow.

Thanks again
Andy

 

[noseall]

Making a 'u' shaped box involves a bottom and two sides, whereby the sides need supporting.

I think what Norcs is suggesting is rather than use something that penetrates the side shutters to tie the sides together, thus leaving a 'scar', use a cross bar that bridges the two sides externally and still allows access for the pour.

 

[Norcon]

Yes thats it noseall.
A top bridging. Which is a little higher to allow finishing off the top.
It could actually be a H shape if made from timber.