retaining wall

[mousiemouth]

My garden boundary is a stream which in the last couple of weeks has become a raging torrent that has taken away a wall and about 14 feet of my garden.I need to get another wall built to stop further erosion quickly. A groundworks contractor has proposed buiding a concrete block wall (the same as the one that came down)with reinforced concrete foundations 200mm thick.The wall will be 450mm for first 750mm of height and thereafter wall thickness reduced to 225mm. He wasn't going to put in any drainage holes in the wall because of the stream on the other side and said water would get in the drainage holes. The total height of the wall will probably be about 4 feet and I'm asking people who know much more than me whether I should trust this man's apparent knowledge and go ahead with wall which will be about 35 feet long and is costing £6,500. Any opinions welcomed. Also should the wall be straight up and down or slanted towards the garden? thanks for any advice.

 

[Norcon]

What you are doing will be OK. A small slant on the wall will relieve some pressure from it but plum is fine.

But £6,500???

The materials will hardly pass £700 and about two days work.
OOh well, its your money.

 

[Chukka63]

i beg to differ with that price.if my sums are correct you need approx 2808 bricks (engineering bricks), 3 ton sand,30 bags cement,if using a 4:1 mix.just under 1.5 metres cube of concrete.we dont know the ground conditions or depth of dig so cant comment.but materials listed above will cost approx £2,500.00.dig out and concrete first day.brick up using an approx average of £400.00 per thousand.builder maybe back filling with top soil???.i would put weep holes in myself to drain the soil when its not raging.if it back flows the stream needs to be level with the garden ,which means the stream is bursting its banks.

id use solid engineering bricks as perforated ones arent that good at withstanding normal weather conditions

 

[mousiemouth]

Thank you both for taking the time to answer. The builder is not using engineering bricks - only concete blocks. He's not putting in any drainage material behind the wall nor any kind of waterproofing- will that be ok on a 4 - 5 foot wall?

 

[Chukka63]

solid or hollow blocks???.id drain the soil,costs peanuts but not draining could cost you double youre now shelling out..get him to put some reinforcing rods in the foundations to anchor wall to founds.again,peanuts and 100% more stable .

 

[Norcon]

(engineering bricks),

You wouldn't use engineering bricks for a project like this!

 

[mousiemouth]

how would he drain the soil behind the wall- sorry for my ignorance?!

 

[Norcon]

how would he drain the soil behind the wall- sorry for my ignorance?!

Some contractors lay a drainage pipe and a few feet of stones.
Some can also be compacted with clay fill layer by layer using an excavator and vibrating roller which effectively seals the back of the wall and reduces the amount of pressure the wall has to withstand.
Have seen this been done a few times if soil and weather conditions permit.

 

[noseall]

The materials will hardly pass £700 and about two days work.
OOh well, its your money.

Are you having an effing laugh!

Either you are completely clueless or a wind up merchant.

 

[Norcon]

The materials will hardly pass £700 and about two days work.
OOh well, its your money.

Are you having an effing laugh!

Either you are completely clueless or a wind up merchant.

No Im not a wind up merchant nor am I completely clueless.
Building retaining walls is what I do for a living and specialise in.
Mostly mass reinforced structures though.
With concrete its about a load which is £50 per cubic meter. The steel will cost about £200 tops.

The last one we did was over 50 meters long and stood 3.5 meters tall.

In the last three years we have pumped some 15,000 cubic meters of concrete into retaining walls with a further 12,000 -16,000 into foundations.
We average about 100 cu meters weekly poured into walling structures.
I take care of the shuttering aspect mostly and have my own team of men.
We own all our own Peri shuttering (rarely have to hire) which is about 300 sq meters and various plant and craning equipment which was built up over the last 25 years from nothing.
All our work is word of mouth.
Never advertised!
Any questions?

An aerial view of our sites wouldn't look to dissimilar to this......

 

[noseall]

If you think a wall of this nature can be finished in two days and with only a £700 outlay then you are seriously misguided.

I suppose if you had a dozen men on board...

Regardless of your blather above i still think you are clueless.

 

[Norcon]

If you think a wall of this nature can be finished in two days and with only a £700 outlay then you are seriously misguided.

I suppose if you had a dozen men on board...

Well there you go. There's 2 men in my squad. On an odd occasion 3.
Count your self lucky you don't have to compete against us.

 

[freddiemercurystwin]

Any questions?

The wall will be 450mm for first 750mm of height and thereafter wall thickness reduced to 225mm. The total height of the wall will probably be about 4 feet and 35 feet long.

Not forgetting something then? What a Bozo!

 

[Thermo]

dont think its an unreasonale cost, as the site conditions near a stream sound akward as well.

when ever we do similar to these we use hollow blocks threaded over rebar from the founds and fill with conc. I would put weep holes in definetly

 

[Norcon]

Any questions?

The wall will be 450mm for first 750mm of height and thereafter wall thickness reduced to 225mm. The total height of the wall will probably be about 4 feet and 35 feet long.

Not forgetting something then? What a Bozo!

I don't think Im forgetting anything.
We compete against block layers now and again and their prices are usually lower.
You're looking at about 400 blocks for this I believe.

My apologies if I offended anyone.
Thermo's suggestion is a good one.