Im an idiot. Led down the garden path on gabion construction.

[dampsquid]

So I had a plan for a gabion wall. I researched loads and came up with a design which had nice angular stone at the front and was backfilled with a load of concrete block from the demolition of the previous terrace.

I hired a contractor who was very well reviewed, has dug basements under houses and done all kinds of civils work, with photos and videos to prove it.

I hired him to dig out so that I could put in the footing.

After discussing my plans in depth he gave me some advice which boils down to:

1. Get solid dense concrete blocks for the face, since it's cheaper than stone.
2. Dry stack these to the face and backfill with the concrete waste.
3. A 1.5m base layer is overkill and actually increases the risk of overturning since the face of the wall is going to be flush.

I don't know why but I listened to this guy, he seemed really knowledgeable and said he had built 100s of these walls.

I ordered the blocks and he helped me build the baskets. He was done digging out and I was paying for a week either way, so he didn't gain anything by giving me this "advice"

He also installed the land drain...underneath the baskets themselves, he said that's how it's done the water drains through the bottom. That's when I began to doubt his credentials.

Then he said to my wife it would be fine if we wanted to pull them forwards onto the flags, without lifting up the flags. So by this point alarm bells are going off. He left with the bottom row complete and one of the top row almost filled. He machine filled the bottom row mostly and I'm concerned they could be quite big voids further down into the baskets.

After the fact I have googled gabions filled/faced with concrete blocks and I've never found anything like it.

My concerns are that i am left with a gabion wall that is not as free draining as rock would be, that has the drain underneath the sub base instead of behind the wall, that if it where to fail is more likely to overturn than bulge as it would with rock. My number 1 fear is that this is going to fall over on my daughter. I think I'm going to have to dismantle the whole thing and start again. Spent over a grand on baskets and a grand on blocks to end up with the worst of both worlds.

Are my fears justified, would you start again? The labour is going to be intense and my neighbours already hate me. But I don't think I'll sleep again. Why am I such an easily lead naive tw*t.

 

[stevie888]

It's unlikely to fall over and it will drain but by the blue cringe it looks stupid: you could have just built a block wall. What a clown you employed;.

I've done gabions with rock at the front and basically hardcore behind: there is a lot of handwork involved to do the job right.

 

[dampsquid]

It's unlikely to fall over and it will drain but by the blue cringe it looks stupid: you could have just built a block wall. What a clown you employed;.

I've done gabions with rock at the front and basically hardcore behind: there is a lot of handwork involved to do the job right.

I've decided I'm gonna dismantle it and build a block wall then I can at least render/paint.

You're right it looks ****e and the falling over things will always be on my mind because its built wrong, the standard design is that it's set back at a batter to the earth and has a drain behind it not underneath the thing.

It looks well packed at the top because I've hand laid the top half of the baskets, but I could only get so far the chunks of concrete at the bottom are too heavy to move about, I'm concerned that there is basically 1 ton of concrete blocks facing each of the baskets, if there was any big movements in the freeze/thaw that the over turning potential is there especially with them stacked at a 2:1 height to base ratio.

Revised plan is to take the 2nd row basket down (only one second row filled), remove all the blockwork from the face and sides of the bottom row. Unclip the face panel of the gabion basket and move it in 400mm back so ive basically got a 60% gabion with just the infill crap behind. Pour a concrete foundation, build a block wall in front of the infill, drainage pipe and some limstone chippings behind, backfill it.

Will try and sell off the rest of my spare baskets and chalk it off as an expensive lesson.

 

[scbk]

I like natural stone. But in a way I don't dislike the concrete blocks, looks quite modern.

I was working at an architects house, it was actually built by his father in law who was also an architect. The walls of the house and garage are bare concrete block. At first I thought it was mad, it looks unfinished. But then it grew on me. Realised you have a finish that is totally maintenance free. No render to fall off, and not having to paint it every ten years - the house has been up for decades.

 

[Deluks]

Horses for courses.
It looks like the goods yard of a builders merchants.

As stated, it won't be affected by frost or fall onto anyone, but It would look better done the proper way.
Or you could always clad it with timber!

 

[dampsquid]

Horses for courses.
It looks like the goods yard of a builders merchants.

As stated, it won't be affected by frost or fall onto anyone, but It would look better done the proper way.
Or you could always clad it with timber!

I mean it's the falling over thing that is my main issue tbh.

As you say I can cover it up with cladding or whatever. But I can't say for sure that its not gonna fall over. That's what is stressing me out.

I'd much rather finish off the 4 baskets as is and figure out how to make it look nice after. But I read some **** about people scooping out dogs from under collapsed walls and can't get that image out of my head. Realistically there is 2 ton of downwards pressure from the top basket which is holding back significantly less earth. But are they still front heavy idk.

Would have to pay someone to come and do the actual block wall and could get the gabions finished this weekend.

 

[Deluks]

They are flat stacked and bonded, so they're not as front heavy as you might think.
I've never heard of anyone digging dead dogs out from failed walls, in Gaza maybe?

 

[robinbanks]

But are they still front heavy idk.

No. There is no fulcrum for it to rotate around, no eccentricity to the mass, no centre of gravity outside the confines of the gabion basket.

You could create a square metre wall out of concrete blocks then glue a cubic metre of polystyrene to the back of it. Adding the polystyrene doesn't spontaneously make it more likely that the whole thing falls over "because it is front heavy".

A dice with a penny glued to the side of it doesn't magically automatically tip so the penny is flat on the table.

When your 28 stone mother in law and her 28 stone husband sit in the front and back passenger seats of your car it doesn't abruptly keel over onto its side in the middle of the driveway "because it is left heavy"

Cease your irrational thoughts; they're not rooted in any sensible physics

 

[Deluks]

Alright Professor Calculus, leave his mother in law out of it!