Retaining wall ideas

[geoffw]

Hi,

This one concerns PPOR.

Behind the house, there is an area which has been excavated. The block slopes heavily; the excavated area consists mostly of stone or rock. It's been that way for ten years, and is very stable. There's no structural need for a retaining wall- it's all cosmetic.

The cutaway bit slopes up at 45 degrees. It's too rocky to grow anything.

The area is big- about 40m length, 1 to 1.5 m high.

Behind the area is natural bush growth.

The retaining wall solutions I've seen so far are either not suitable for an "aesthetics only" retaining wall, or are Waaaay to expensive.

My personal option was to grow plants to cover the area. That's been rejected by management.

Any ideas for a cost effective/good looking wall please?

thanks

Geoff

[Kevmeister]

Expensive is a relative thing. What sort of quotes have you been getting?

Boral have a range of individual masonry unit walling systems. Some are interlocking but only suitable up to about 600 high, whilst others are capable of much greater heights with engineering advice.

If it's for aesthetic reasons then why would you want a massive retaining wall 1.5m high? For aesthetic reasons I'd go for something no higher than a metre, and use your idea to plant up the area. Plants are commonly used to keep sand dunes stable, so the principle should surely apply to your situation. Ideally you'll want plants they have the capacity to block out weeds (eg. groundcovers) because weeding a 45 degree slope ain't gonna be much fun.

Besides that, you've got the option of sleepers (redgum or treated pine), also cantilevered concrete. This is like an L shaped concrete such that the "flat" of the L cuts back into the area you are retaining and the weight of earth on top of the "flat" of the L prevents the structure from overturning.

Is there any possibility of rubble working loose and sliding down the slope, damaging the house.

Consider the longevity of the solution when you consider the cost. The masonry retaining walls probably last forever if done correctly, whilst timber rots.

Kevin.

[geoffw]

Thanks for that Kevin.

I haven't sought quotes yet- it's a long term problem, and MrsW is (quite rightly) asking for a way to make the house and grounds look better. I'm just worried about how much it will cost.

The last time I looked, it would have coist very many thousands for one of the interlocking blocks solutions. But i'd be interested to know about and costs per sqm.

Are there options of any brick/terracotta solutions vs the stone-lookalike products?

Any wood solution is out. Because it already slopes backwards 45 degrees, with only about two metres between the start of the slope and the back of the house, wood would take away space.

I guess I was hoping for a really innovative solution which would not cost huge amounts.

There is absolutely no possibility (imho) of rubble working loose- the cut has been there for ten years already, with a big hill behind and masses of water already pouring over in the past. It was cut out of very stony and solid base.

The one meter height plus planting sounds good. I'm not sure about the cantilevered concrete- it may take up too much space. Because the need is cosmetic rather than practical, any solutions I've seen so far seem to be overkill.

Thanks for those ideas though- there's a few options to investigate.

[Michael Croft]

Hi Geoff,

Obviously this issue isn't going anywhere in a hurry so if you are prepared to put in some sweat equity; hire a truck, come out to my farm, gather as many lichen covered rocks as required and do a free stone wall.

Don't want to get callouses or bend your back? Hire some Uni students to do it all under your supervision.

regards, Michael Croft

[geoffw]

Michael,

Many thanks for that. It may well be a great way out.

I will have to investigate a little on stonewalling. But that could well be a winner. Thank you.

Our personal supply of rocks may have been greater. Our block is largish, and with many rocks (though not lichen covered). We drove home one day- and, on our property, was one of our neighbours, with a barrowload of rocks- ready to complete building his own retaining wall.

And I have a few student tenants who may well be glad of a few extra readies.

[geoffw]

I've received a private reply on this. I did ask the poster to reply to the forum- but there's no reply so far. I thought it was worth while to share the info- it's very valuable info. (If the poster would like acknowledgement, I'd be glad to)

Hi Geoff

Don't know if you ever got your walls done, but I have found the following solution great and extremely low cost for long walls.

I have done retaining walls by using limestone blocks 1000mm x500mm x 500mm seconds. They cost from memory about $10ea.

The footings are a simple trench about 100mm deep and are just the existing soil, levelled and straight.

I hired a bobact for a couple of hours to move the blocks around as they have a special sling. They charge in the region of $40hr
and you will only need them for two to three hours.

We ran two rows of blocks side by side with an end spacing of pvc pipe off cut. There was a space of 150mm between each row which we filled with rubble and concrete scrap later, when we filled in the soil at the rear.

My mate mixed the cement, and i guided the blocks into position for the second level, in a brick bond pattern. Because of the bobcat, we had a 26m long by 1m high wall erected in two hours.

After the concrete had dried enough, I mixed up a white concrete and trowelled it into the gaps on the facing side, and allowed it to go slightly off. I then got a bucket of water and a broom head and scrubbed the joints down to smooth them off and clean it all up.

The end result? $400 approx in cost for a wall I was quoted up to $5000 to install.

Hope it helps

[bundy1964]

Hi GW

What about a cheap render with some colour added?

bundy

[geoffw]

Bundy,

What's there at the moment is just stone- what's been left behind from an excavation.

Not sure that a coat of render straight onto raw stone would work well.

But it may trun out that render on besser bricks would work. The besser bricks would have to be installed at an angle.

But I like the idea of sandstone seconds. That really appeals- especially to MrsW (where it counts)

[bundy1964]

There is always Groundforce or Backyard Blitz ;)

Mrs W may like to get on tv :p

bundy

[geoffw]

Hehehe

Gee, thanks Bundy.

MrsW has beeing praying for that for a long time. Except that she's been passing requests to her deity via me :D

I think our yard is too big even for ground force. A 2400sqm block- bush block, backing reserve, built 10 years ago, and minimal landscaping done since.

[Ruby]

You might not have rocks as nice as MC, Geoff. :D

But, paint a little milk on to the surface of the rocks and the lichens will soon develop.

Ruby :)

[michaelg]

Hi,

If you do decide to go with something like the Boral retaining wall bricks, ask for a quote of the "seconds".

"seconds" are factory seconds which the colours are not "perfect" (and they dont vary that much), and are much cheaper, I bought 2nd's pavers and bricks for a small deck out back.

Michael G

[Kevmeister]

I think our yard is too big even for ground force. A 2400sqm block- bush block, backing reserve, built 10 years ago, and minimal landscaping done since.

Hmmm. Backyard Blitz might do *something* but GroundForce, forget it. What could they possibly do with $3500 on a 2400 square metre block? It would cheap and trashy. Better *not* wish for it.

(BTW, I am trying to find a good landscape designer/contractor at present and none of them I've spoken to like either show... he he. And don't ask a paver about the way they lay their pavers on a crushed rock base - eek).