Walls that hold their ground.

Interlocking concrete blocks. Stacked dry, without mortar.

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A stepped retaining wall of large interlocking concrete blocks holding back a garden of grasses, shrubs and a small tree
One Drylaid block: a long concrete block with two rows of four tapered studs along its top, two lifting anchor points between the rows, and two keyways underneath that show as notches at its end

One block. 3,600 pounds.

No mortar
Studs on top sit in keyways under the block above.
Two lifting anchors
Cast in, below the top face. Clip on two chains and lift.
Yours to move
Take the wall apart and build it elsewhere.

What it builds.

We build our own steel moulds and cast every block ourselves.

We sell the blocks, not the moulds.

The mould.

Two steel halves, wedged shut at two corners. These are working drawings, in inches, and stay provisional until the first pour.

Plan of the closed mould on its casting table: two L-shaped steel halves around a 72 by 24 inch cavity, with four stud pockets along one long wall, two full-length troughs on the other, two lifting anchors, and at each of two diagonal corners a lock tab passing through the other half's flangeStud wall: pockets press outward and cast the studs on topConcrete, 24″ deep. The open face is trowelled.Recess wall: two folded troughs cast the keyways underneathLock 1: three stationsLock 2: three stations9″18″18″18″9″72″ inside24″Casting table: one 4 × 8 ft plate, 96″ × 48″, on 15 levelling feetRings are lifting eyes. Blue dots are base bolts into the table. Black squares are locating stops.
From above, closed, on the casting table. The block is cast on its side.
Elevation of one opening corner: at three heights a shelf on the end wall passes through the long wall's flange as a tab, with a flat wedge dropped through the tab outside the flange and a round backup pin beyond it, and the clear space a hammer needs above and below each wedge markedend wallBase bolt into the tablecasting table5½″6½″6½″5½″4½″ tabOpen above the top wedgeNothing overhangs the tab.Wedge, straight edge to the flange5″ long, 1⅞″ to 1⅛″ wide, ⅜″ plateBackup pin and clip¾″ pin in a ⅞″ hole4½″ clear between stationsThree stations a corner: six wedges, six pins.Tab through the flangeThe shelf runs through a slot in it.Key gapThe T-end key twists in here.2⅛″ under the lower tipKnock it up from below, at an angle.
One opening corner, from outside the end wall.
Wedges clamp
Each shelf runs through the other half’s flange as a tab. A wedge dropped through it draws the corner tight. Three to a corner, six in all.
Pins back them up
A round pin and clip beyond each wedge keeps the tab in if a wedge works loose.
Bolted at the base
A bolt each side of the corner holds the bottom to the table, where the concrete pushes hardest.
Room to swing
Nothing sits above or below a wedge. It is driven down and knocked back up with a hammer.
A key opens it
With the wedges and pins out, a flat T-ended key goes in the gap and twists the halves apart.
The loose parts of one lock station: a tapered flat wedge, a round pin with a spring clip, the drilled and slotted tab, and the T-ended opening keyseats here1⅞″5″1⅛″ at the tipWedge¾″ roundPin and clip4½″flangeslot 1¾″ × 7⁄16″, along the tab⅞″Tab, from aboveTwist it in the corner gap32″ long, ⅜″ plateOpening key
The loose parts of one lock.
Section across the wall through one stud seated in the keyway of the block above, showing the clearance around it and the taper that lets the mould release2¾″ stud top6″ stud base1¾″¼″ cleareach side43° taperblock aboveblock below
A stud in the keyway of the block above, seen along the wall. The taper is what lets the steel come away.
The stud wall seen from inside the mould: eight square pockets in two rows, and two anchor magnets on the centreline, with a section showing one pocket as a pressed steel cup welded into a square cut-out72″24″18″ stud centresAnchor magnetsOn the centreline, between stud columns.concreteStud cupWelded into a6″ square cut-out.Flange, weldedoutside the wall6″
The stud wall from inside. Each pocket is a stud cup welded into a square cut-out. The two rings between the rows are the anchor magnets.
The recess wall seen from inside the mould: a flat steel wall with two folded troughs running its full length, one under each row of studs, one under each row of studs. A section shows one trough as a folded strip welded to the flat wall72″24″Two troughs, end to endOne under each row of studs.Capped at the end that opensconcrete6½″2″ deepFolded trough11 gauge, two bends,3″ flat crown.Flat wallNo cut-outs, no cups.
The recess wall from inside. Two folded troughs run end to end and cast the keyways the studs sit in, so courses can be set at any offset along the wall.
Two details. A steel bevel strip in the corner where the mould wall meets the casting table, which gives the block a bevelled edge. And the stud cup laid flat as one laser-cut blank: a square top with four flaps that fold up, each with a flange for weldingEdge bevelconcreteBevel strip¾″ on every edge.Edges stop chipping.wallcasting tableStud cup, laid flatOne laser-cut blankFour flaps fold up; seams are welded.Rounded bends⅜″ inside radius, so studs do not chip.Flange¾″ wide, welded outside the wall.
Edges and studs. A bevel strip runs along every edge of the block, and each stud cup folds up from one blank with rounded bends.
The lifting anchor in section. In the mould, a magnetic former on the steel wall holds a plain spherical-head pin with a rubber ring around its head. In the finished block, the head sits in a round recess below the top face and a lifting eye clips over itIn the mouldMagnetic formerStays on the mould wall.Rubber ringPeel it out afterwards.6¾″ pin, no thread3″In the blockLifting eyeClips over the head.Recess3″ across, 1¼″ deepHead below the faceSet back ⅜″, so blocks stack.
The lifting anchor. A magnet holds it while the concrete goes in, and nothing is threaded.
The logo liner from above and in section: a plastic tray the size of the mould floor with a raised panel and the lettering sunk into it in mirror image, which casts raised letters inside a sunken panel on the side of the blockrylaid71¾″23¾″Clipped cornersClear the bevel strips.Raised panelLettering is mirrored.Lip all round⅛″ clear of the walls.concrete⅜″Raised panelSinks a panel into the block.Sunk letterStands up, level with the face.Hollow under the panelBack it so it cannot flex.3⁄16″ sheet on the casting table. The section is not to scale along its length.
The logo liner. A formed plastic tray on the mould floor puts raised letters in a sunken panel on the side of the block. Nothing fixes it; the concrete holds it down.
The casting table from above and from the side: a 96 by 48 inch steel plate on a channel frame with cross-members every 12 inches and fifteen levelling feet on threaded rodlocating stopsmould sits here, 82″ × 34″96″48″12″ between cross-members¼″ plate on 3″ channelLevelling feet on 1″ threaded rod, with a lock nutuneven ground
The casting table. One 4 × 8 ft plate on a channel frame, levelled on screw feet so the block comes out square and no slurry leaks under the mould.

From oil to lift

  1. Level the table. Seat the first half against the stops, close the second onto it, drive the wedges, drop the pins, tighten the base bolts.
  2. Oil every inside face: walls, stud pockets, troughs, magnets and the table. A thin film, no puddles.
  3. Set each lifting anchor on its magnet, with its rubber ring on.
  4. Pour in layers and vibrate. Trowel the open face.
  5. At 24 hours, pull the pins, knock the wedges up and open the halves with the key. Left longer, it opens harder.
  6. Lift the block by its anchors, never the mould with the block in it. Turn it upright on a turner, or over two old tyres.

Sizes.

BlockSizeWeight
Drylaid 180First mould72 × 24 × 24 in6 × 2 × 2 ft, about 183 × 61 × 61 cmabout 1,600 kg (3,600 lb)
What do I need to lift one?

A forklift, loader, telehandler or excavator rated above the block’s weight. Two chains clip onto the lifting anchors, or a block clamp grips it by the sides.

What does it sit on?

Firm, level ground: compacted gravel, concrete or asphalt.

How high can a retaining wall go?

It depends on the soil and the slope, and taller walls need an engineer’s design. Tell us about the site.

Can a wall come apart again?

Yes. Nothing is mortared, so the blocks lift off and stack somewhere else.

Do you sell the moulds?

No. We build them for our own casting and sell the finished blocks.

Tell us about your wall.

No drawing needed. We’ll count the blocks and send a price.

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