A retaining wall is a structure that acts like a wall holding back soil. A retaining wall might be to keep soil from flooding into your home with heavy rains, or it might be to hold back soil and create a patio or outdoor space if your home is built into a slope. 

Retaining walls come in all different types, so there will be a style of retaining wall to compliment your home and budget. Retaining walls can also be used to create garden beds and terraced style gardens.

What are the different types of retaining walls?

The four main types of a retaining walls are;

  1. Cantilever
  2. Gravity
  3. Soil Reinforcement
  4. Anchor retaining

  1. Cantilever retaining walls

This is built using reinforced concrete, with an L-shaped or inverted T-shaped foundation.
Cantilever retaining walls are further broken up into different types;

  • King Post
    Steel UC columns driven or cast into augured post holes. Concrete panels or timber sleepers are slid down the channels to fill the gap between the posts.
  • Sheet Pile
    Steel sheet piles driven in the ground, then tied back using ground anchors.
  • Secant Walls
    A continuous line of bored and concrete fill piles, common when building large basements.
  • Precast concrete L shaped
    Can be bolted down or cast in a concrete foundation, the units are made in a precast concrete factory and brought to site. 
  • Hollow block L Shaped
    Blocks are laid on top of a reinforced raft with started bars, then cement is used to fill the cavity of the block.

 

  1. Gravity retaining walls

These walls use their own weight to hold back the earth, the four main types of gravity retaining walls are;

  • Gabion basket
    Steel baskets filled with various size stone.
  • Criblock
    Constructed from timber or concrete frames and filled with stone.
  • Concrete block
    Interlocking concrete blocks.
  • Masonry
    Walls built using bricks.

 

  1. Soil Reinforced retaining walls

Created by excavating layers of soil and placed on top of a geogrid. Geogrid sheets reinforce the soil and the soil becomes the retaining structure. Concrete blocks wall are connected to the geogrid layers.

 

  1. Anchor Retaining Walls

A wall is constructed and then given strength to the wall by  using cables or steel bars anchored in the rock or soil behind by being bored into the ground.

What is the cheapest way to build a retaining wall?

The cheapest retaining walls to hold a massive amount of earth back would be masonry bricks that are filled with concrete as well as gabion baskets filled with stone.

If the retaining wall is for a garden bed so not as much earth, then wood would suffice. The wood will need to be pretreated to withstand the elements of being semi buried into the earth. These can be wood blocks or even wood sleepers.

How much will it cost to build a retaining wall?

The cost of building a wall is of course the labour time of the builder, but then the expense of the materials. Building a brick retaining wall versus a stone retaining wall might be a similar amount of labour time but the material costs will vary greatly. Before speaking with the builder do your research on which style wall will best suit your property and be strong enough for the amount of soil the wall needs to hold back. Then take into account the access to the area and location on your property. If living in a terraced house could a small digger be taken around to the back of your garden or will the foundation have to be dug by hand adding days of labour onto the cost of the retaining wall?

The height and width of the wall will depend on how deep the foundation needs to be dug and there will be a cost involved for the removal of the excavated soil. The ground conditions will affect the price as sandy soil equals better drainage than clay soil, and this too will influence the materials needed for the construction of the retaining wall as will the extent of the slope the wall needs to hold back.

Cost to build a retaining wall

Per

Average total labour cost

Build a 5 metre long gabion retaining wall

Per day

£280

Build a 5 metre long brick retaining wall

Per day

£300

Build a 3 metre long wooden garden retaining wall, ½ metre high

Per day

£200

Repairing a concrete 5 metre long retaining wall

Per day

£200

Creating drainage holes on a concrete 5 metre long retaining wall

Per day

£180

Does my retaining wall need a foundation?

In short, yes. Another term for foundation of a retaining wall is footing.  The footing is important as over time the ground will shift causing the wall to shift and this can result in the wall falling down. The wall also needs good drainage to avoid a pressure being created against the wall from water which also can eventually push the wall down. The depth of the foundation will depend on how tall the retaining wall needs to be, e.g.; a four foot wall needs 9 inches of foundation with an inch being crushed rock to keep the retaining wall stable.

The foundation should also be wider than the wall and double the depth, for added stability.

As well as ensuring a foundation, the retaining wall needs to be suitably thick to hold back the earth. The least thick a wall should be is the depth of a house brick. A formula to work out best thickness is taking the thickness as a quarter of the depth of the soil, e.g. 150cm deep divided by 4 (1 quarter) = 37.5cm thick.

How often do I need to replace my retaining wall?

If the builder has built your retaining wall with good drainage and a solid foundation, depending on the material used, the wall should see you through 25-100 years. Over the years, check on the health of  your retaining wall, noticing any signs of flooding, deep cracks, bending or loose mortar.  Certain cracks or loose mortar a builder might just be able to repair and maintain the wall to stop the wall from crumbling. If drainage is an issue, see if a builder can retrofit some drainage points or weep holes.

If the retaining wall is buckling, speak to a builder about strengthening the foundation, possibly adding deeper anchors to secure the wall. It is a lot easier to repair a retaining wall than the expense of removing the wall to build a new retaining wall. The only time the builder will want to replace a wall is if there is no other option to save the existing retaining wall.

How many years will a retaining wall last?

This question is dependent on the type of material used to construct the retaining wall and as already touched on, the amount of drainage and solid foundation. A tough material like stone might not last 10 years, nevermind a 100 years if it has no way of draining out the water.

Average life span for different types of material:

Stone; 50 – 100 years
Stone makes for an attractive and sturdy wall without the concern of insects infesting in the wall, however certain stone can be very costly and this wall comes with limited colour choices.

Wood; 25  -40 years
An inexpensive way to create a retaining wall with a natural look but will not last as long as other retaining walls and must be weather treated as well as pest treated.

Brick; minimum of 100 years
An easy to create, pretty option that complements many gardens and is weather resistant but there are not many colour options.

Concrete;  a 100 years
This is a good mid-range costing wall, allowing many design options to create a feature in the garden aside from the practicality point of a retaining wall. The builder will need to factor in the need for drainage as this does not naturally occur like with stone.

Gabion;  50 -100 years
Gabion walls are easy to install without the need for deep foundations and have a great lifespan and require little or no maintenance. Plants can be grown to flower over the wall and the vegetation can help strengthen the wall. This style however does not suit all properties.


Estimates for common builder jobs;

Job Estimate
Cost to fit windows, doors and conservatories £160
Cost to build a side return extension £61000
Cost to repoint or repair brickwork £405
Cost to remove a chimney breast £800
New fitted kitchen cost £19500
Cost to lay a new driveway £3400
Cost to fit a new bathroom £8000
Cheap fixed rate mortgage 4.00 %
Cost of a loft conversion £49900
Cost of home insurance £20.00 per month
Cost of contents insurance £12.00 per month
Cost of building insurance £10.00 per month
Cost to build a retaining wall £320
Basement conversion cost £43000

Rates for other trades

Build retaining wall cost in the UK
Build retaining wall cost in the UK (excluding VAT or callout charges)
Location in UKBuild retaining wall cost
Build retaining wall near Aberdeen£290
Build retaining wall near Amber Valley£244
Build retaining wall near Angus£235
Build retaining wall near Arun£257
Build retaining wall near Ashfield£248
Build retaining wall near Aylesbury Vale£255
Build retaining wall near Barnsley£273
Build retaining wall near Basildon£261
Build retaining wall near Basingstoke & Deane£265
Build retaining wall near Bassetlaw£246
Build retaining wall near Bath & North East Somerset£258
Build retaining wall near Bedford£282
Build retaining wall near Belfast£172
Build retaining wall near Birmingham£233
Build retaining wall near Blackburn£233
Build retaining wall near Blackpool£218
Build retaining wall near Bolton£233
Build retaining wall near Bournemouth£261
Build retaining wall near Bracknell Forest£278
Build retaining wall near Bradford£239
Build retaining wall near Braintree£253
Build retaining wall near Breckland£218
Build retaining wall near Bridgend£222
Build retaining wall near Brighton£255
Build retaining wall near Bristol£257
Build retaining wall near Broadland£211
Build retaining wall near Broxtowe£244
Build retaining wall near Bury£238
Build retaining wall near Caerphilly£226
Build retaining wall near Calderdale£228
Build retaining wall near Cambridge£269
Build retaining wall near Canterbury£229
Build retaining wall near Cardiff£226
Build retaining wall near Carmarthenshire£219
Build retaining wall near Charnwood£221
Build retaining wall near Chelmsford£257
Build retaining wall near Cheltenham£260
Build retaining wall near Cherwell£262
Build retaining wall near Chester£229
Build retaining wall near Colchester£248
Build retaining wall near Conway£219
Build retaining wall near Coventry£230
Build retaining wall near Crewe & Nantwich£252
Build retaining wall near Dacorum£272
Build retaining wall near Derby£244
Build retaining wall near Doncaster£245
Build retaining wall near Dover£229
Build retaining wall near Dudley£233
Build retaining wall near Dumfries & Galloway£200
Build retaining wall near Dundee£244
Build retaining wall near East Ayrshire£228
Build retaining wall near East Devon£204
Build retaining wall near East Dunbartonshire£254
Build retaining wall near East Hampshire£261
Build retaining wall near East Hertfordshire£278
Build retaining wall near East Lindsey£235
Build retaining wall near East Riding£246
Build retaining wall near Eastleigh£260
Build retaining wall near Edinburgh£272
Build retaining wall near Elmbridge£276
Build retaining wall near Epping Forest£270
Build retaining wall near Erewash£242
Build retaining wall near Exeter£203
Build retaining wall near Falkirk£241
Build retaining wall near Fife£260
Build retaining wall near Flintshire£233
Build retaining wall near Gateshead£254
Build retaining wall near Gedling£245
Build retaining wall near Glasgow£276
Build retaining wall near Gloucester£246
Build retaining wall near Guildford£286
Build retaining wall near Gwynedd£193
Build retaining wall near Halton£228
Build retaining wall near Harrogate£231
Build retaining wall near Havant & Waterloo£255
Build retaining wall near Highland£230
Build retaining wall near Horsham£262
Build retaining wall near Huntingdonshire£281
Build retaining wall near Ipswich£233
Build retaining wall near Isle of Wight£257
Build retaining wall near Kings Lynn & West Norfolk£221
Build retaining wall near Kingston-upon-Hull£236
Build retaining wall near Kirklees£242
Build retaining wall near Knowsley£219
Build retaining wall near Lancaster£234
Build retaining wall near Leeds£237
Build retaining wall near Leicester£215
Build retaining wall near Lisburn£173
Build retaining wall near Liverpool£223
Build retaining wall near London£272
Build retaining wall near Luton£266
Build retaining wall near Macclesfield£237
Build retaining wall near Maidstone£269
Build retaining wall near Manchester£236
Build retaining wall near Mid Bedfordshire£277
Build retaining wall near Mid Sussex£255
Build retaining wall near Middlesbrough£243
Build retaining wall near Milton Keynes£271
Build retaining wall near Neath Port Talbot£225
Build retaining wall near New Forest£265
Build retaining wall near Newbury£261
Build retaining wall near Newcastle-under-Lyme£233
Build retaining wall near Newcastle-upon-Tyne£256
Build retaining wall near Newport£236
Build retaining wall near North Ayrshire£248
Build retaining wall near North East Lincolnshire£246
Build retaining wall near North Hertfordshire£277
Build retaining wall near North Lanarkshire£247
Build retaining wall near North Lincolnshire£219
Build retaining wall near North Somerset£257
Build retaining wall near North Tyneside£261
Build retaining wall near North Wiltshire£247
Build retaining wall near Northampton£256
Build retaining wall near Norwich£214
Build retaining wall near Nottingham£246
Build retaining wall near Nuneaton & Bedworth£231
Build retaining wall near Oldham£239
Build retaining wall near Oxford£267
Build retaining wall near Pembrokeshire£180
Build retaining wall near Perth & Kinross£252
Build retaining wall near Peterborough£276
Build retaining wall near Plymouth£244
Build retaining wall near Poole£264
Build retaining wall near Portsmouth£254
Build retaining wall near Powys£230
Build retaining wall near Preston£233
Build retaining wall near Reading£277
Build retaining wall near Redcar & Cleveland£246
Build retaining wall near Reigate & Banstead£277
Build retaining wall near Renfrewshire£286
Build retaining wall near Rhondda, Cynon, Taff£225
Build retaining wall near Rochdale£237
Build retaining wall near Rotherham£270
Build retaining wall near Salford£233
Build retaining wall near Salisbury£313
Build retaining wall near Sandwell£232
Build retaining wall near Scarborough£233
Build retaining wall near Scottish Borders£292
Build retaining wall near Sefton£225
Build retaining wall near Sevenoaks£270
Build retaining wall near Sheffield£277
Build retaining wall near Slough£280
Build retaining wall near Solihull£230
Build retaining wall near South Ayrshire£233
Build retaining wall near South Bedfordshire£282
Build retaining wall near South Cambridgeshire£274
Build retaining wall near South Gloucestershire£256
Build retaining wall near South Kesteven£226
Build retaining wall near South Lanarkshire£221
Build retaining wall near South Oxfordshire£270
Build retaining wall near South Somerset£289
Build retaining wall near South Tyneside£258
Build retaining wall near Southampton£259
Build retaining wall near Southend-on-Sea£250
Build retaining wall near St Albans£274
Build retaining wall near St Helens£220
Build retaining wall near Stafford£242
Build retaining wall near Stockport£240
Build retaining wall near Stockton-on-Tees£245
Build retaining wall near Stoke-on-Trent£234
Build retaining wall near Stratford-on-Avon£234
Build retaining wall near Stroud£245
Build retaining wall near Suffolk Coastal£224
Build retaining wall near Sunderland£253
Build retaining wall near Swale£247
Build retaining wall near Swansea£239
Build retaining wall near Tameside£240
Build retaining wall near Teignbridge£227
Build retaining wall near Tendring£239
Build retaining wall near Test Valley£248
Build retaining wall near Thamesdown£247
Build retaining wall near Thanet£211
Build retaining wall near The Wrekin£259
Build retaining wall near Thurrock£264
Build retaining wall near Torbay£244
Build retaining wall near Trafford£239
Build retaining wall near Vale of Glamorgan£233
Build retaining wall near Vale of White Horse£260
Build retaining wall near Vale Royal£236
Build retaining wall near Wakefield£240
Build retaining wall near Walsall£233
Build retaining wall near Warrington£236
Build retaining wall near Warwick£232
Build retaining wall near Waveney£235
Build retaining wall near Waverley£287
Build retaining wall near Wealden£251
Build retaining wall near West Lancashire£223
Build retaining wall near West Lothian£264
Build retaining wall near West Wiltshire£247
Build retaining wall near Wigan£228
Build retaining wall near Windsor & Maidenhead£280
Build retaining wall near Wirral£224
Build retaining wall near Wokingham£276
Build retaining wall near Wolverhampton£233
Build retaining wall near Wrexham Maelor£244
Build retaining wall near Wychavon£236
Build retaining wall near Wycombe£274
Build retaining wall near York£226