Retaining wall project.

[cynic]

Greetings, discoverd this mine of info a few weeks ago and figured i'd throw my lot in.

Bit of a DIY nurd , done my own heating, stud, bathroom. fishtank base for a 300l tank, terraced the garden, shed, my drive (can handle a 44t tractor parked on it) etc.

Finaly reached a point where i fancy a second opinion from outside my own circle of mates to check my thoughts on my lates progect if you don't mind.

To bussiness, a good friend of mine has a rather disasterous issue where his garden is falling into his neighbours, owing to a previous resident now long left deciding to terrace his side. Lots of mumbo jumbo. Short vertion is he's got to deal with it. Enter me.

His garden is actually on average 2ft above his neighbours, he wants (well his missus) wants the garden level. This means taking it up another 18 inches.

My plan is: (this is where i get shot down)

(23ft garden boundry)

12inch by 2ft foundation by 23ft, concrete (1.5cuY)
(supplied mixed),reinforced with rebar mesh.
Vertical reinforcement of rebar (12mm) within double width hollow 7nm blocks (which are channeled for horisontal rebar)
5 course of these blocks with 3 piers, these blocks filled with concrete around the rebar both verticle and horisontal.

Still undecided as to drainage as whatever i do it will drain into the neighbours garden, weep holes or land drain? Weep holes i think...

From bottom of footing to the top will be 4ft 6 or therabouts, of which roughly 6-8 inches will be above ground on Pauls side and around 3ft on the neighbours, screened by their apallingly bad fence.

With the footings i'm going to include the fence posts for a 6 foot inch spaced open pattern fence (so wind can pass) as a final screen as they are looking directly into their neighbours bedrooms almost. Yuk.

There is no water table issue as that is well below Pauls garden, i may be a bit ott but its all on, ready, CLAY. Sorry if its a bit much, digging the hhhuuuuggggeeee trench at the mo.

OK bring on the comments, i can take it.....honest....

 

[Static]

Probably wont need the horizontal lacer bars in the retaining wall stem if you put a B12 in each hollow core should be more than sufficient. Would also make it easier to build without having to thread bars through..

I would recommend putting in weepholes at about 1.5-1.8m centres and having the screening fence separate from the wall so if it does fall over in a hurricane the wall doesnt come down with it.. either that or beef up the footing width..

ps.. 12mm bars are sometimes hard to come by (16s may be cheaper)
oh and get frost proof blocks..

 

[cynic]

Cheers for the reply, i did wonder if the horisontal bars were being ott.

Thing is once this is in and done there is no access for any maintanance at all. Once its done, its done! I certainly don't want it failing 10years from now.

The builders merchant near me does 12mm rebar in 3Metre lengths for about 4 quid, (more you get cheaper etc) so thats ok.

Any sugestions for the fence?, i'm loath to increace the footing as it will be an epic trench as it is, best part of 5ft at its deepest 300cu ft of digging. Sacrificing garden area is of course worst case.
I was hoping gapping the fence would do it, esp as the fence posts will still be 2ft from the base of the trench even at 8ft long (assuming a 6ft fence).

 

[Static]

Ok.. what kind of clay are you into? and what depth are you taking the base down to below the neighbours ground level?

 

[cynic]

Ok.. what kind of clay are you into? and what depth are you taking the base down to below the neighbours ground level?

As it stands at the minute bottom of the footing is 400below the neighbours garden.

The village is known for being on clay, thick brown heavy stuff with tennis ball sized pebbles in it. Ok to dig though once your into it, comes out in spade sized chunks, bar the pebbles.

I'm wondering if some pits dug into the fotting under the fencpost positions going down another 3-400 and a spade width square would do it? Its a pain as i can't see the fence being secure if it goes in the back fill.

I'll take some pictures at the weekend.

 

[Static]

If you want to fix your fence onto the wall/ontop the wall then you will need a wider footing, about 3ft wide. Even then i wouldnt be 100% sure that the wall wouldnt sink a little over time, unless you have pretty solid clay (which it sounds like its quite weak).

 

[cynic]

Thats a heap extra digging, i kind of figured it would be needed though.

Using the ol half hight guesstimate for the footing gives the 600, but with 6ft of fence on top adding leverage its got to go up.

Like i said this cannot fail, no option for maintainance either so 3ft (900) footing it is.

I'm thinking fit some tubing at the fixing points BEFORE the concrete in the blockwork and then bolting the posts in place after the concreting in the blockwork.