retaining wall - How high

cheepskate_2

Hi

For a retaining garden wall, compacted earth would be behind it, Can anyone foresee any problems that may occur dependent on the height. and length . Would there be any planning issues as such
Any ideas of the work/cost involved in cutting into and disposing of the earth and building the retaining wall . Wall would be approx 11 feet high not too sure of length but maybe 20ft.

ian103

thats some wall, i'd guess you will be looking reinforced concrete, with a fairly wide base slab as well.

not sure about planning but that will be an expensive wall.

27col

I wouldn't want to be anywhere near an 11' high retaining wall unless it was built to an extremely high specification. The weight of the masonry alone would be huge.You are talking about a huge structure that would need to be engineered to a very expensive quality.

cyclonebri1

To be honest the issue is what is the difference in height between the 2 properties, that will govern construction/thickness etc as the retaining factor is almost entirely down to the mass or weight of the masonary.

Also depends if you are high side or low side.

Depending on your situation it may well also invoke the party wall act as foundations will be needed under the neighbouring property.

Planning depends if it is front or rear, rear is not likely to need it, not building regs.


Height wise, planning will govern that on a frontage, but in general it will be cost and the actual purpose of the wall, at this stage only you know the info that's been guessed at here;)

Incidentally, I did my own about 18 months ago, just short of 30mtr and between 1.5 and 1.0 mtr high above ground, max 1mtr height differential.

Mine was 6" block/4" concrete infill with rebar/4" stone facing.

You also need to bear in mind what purpose the high side is used for, simple foot traffic, vehicular use, etc etc, it make a difference as does the soild stability.

So many variables preclude offering views on cost to be honest.

gmgmgm

Completely agree with the other posters. 11ft retaining wall is a major engineering project and will be very expensive. It will be holding back many many tonnes.

cyclonebri1

gmgmgm wrote: »

Completely agree with the other posters. 11ft retaining wall is a major engineering project and will be very expensive. It will be holding back many many tonnes.

It may not, this is the ambiguity of the question, the issue is the difference in height, ie, just what in terms of height is the wall holding out/in??????


Maybe not clear?, an 11 foot high retaining wall could be holding back 11ft of earth, or 3ft and be 8ft high on the high side.

swail

Another great money saving option for retaining wall building are formablok molds that allow you to pour your own free draining interlocking 16x8 landscaping blocks. You can go very high if you add batter to the wall

Fred56

OP, you really need to speak to a structural engineer. Find a proper one with knowledge of soil mechanics through the institute of structural engineers.

Don't neglect your responsibilities under the Party Wall Act which may apply depending upon the proximity to neighbouring property.

I don't think cheap retaining walls exist. I built one to an engineer's design in 2011. About 30m in total along two sides of a sloping plot with a max height of 1.4m. Cost was about 10K inc excavation but excluding the muckaway which was another 18 x £160.

cyclonebri1

Fred56 wrote: »

OP, you really need to speak to a structural engineer. Find a proper one with knowledge of soil mechanics through the institute of structural engineers.

Don't neglect your responsibilities under the Party Wall Act which may apply depending upon the proximity to neighbouring property.

I don't think cheap retaining walls exist. I built one to an engineer's design in 2011. About 30m in total along two sides of a sloping plot with a max height of 1.4m. Cost was about 10K inc excavation but excluding the muckaway which was another 18 x £160.

That's remarkably similar to the 1 I did, 29yds x 1.5/1.0mtr as it sloped to the road.

DIY cost was about half yours, I'm guessing due to the fact that it was replacing an existing structure, most of the removed material was hardcore that went to a local farm rather than landfill;);)

Mine was 1 single length which I guess also reduced the cost

Hintza

If it was me I would be trying to bank as much as possible (if at all possible) and keep the retaining wall height to a minimum. As has been said this is a job for a professional.

cyclonebri1

But don't you just love posts where the op sets it all up for replies over time and then disappears without so much as a thanks for anyone??