Half four the day before, with a tape and a torch
Forty-two metres of basement wall, formed one side, cage tied out, bulkheads standing at both ends and the first truck booked for seven. The kicker was cast a fortnight ago with the slab and has been rained on twice since. Somewhere down in the corner of it there is a waterstop that was hog-ringed to the starter bars before anybody had walked through here with a hose. Tomorrow morning the second form face closes and nobody sees any of this again for the life of the building.
That asymmetry is the whole reason for the walk. A folded waterstop found tonight costs twenty minutes and a pair of pliers. The same folded waterstop found in eighteen months costs a specialist injection contractor, a scaffold in a finished plant room, a fee argument about who was responsible for the pre-pour inspection, and a client who now believes the basement leaks generally rather than at one identifiable metre of one identifiable joint. Below the water table there is no outside to go back to.
So the walk answers three questions and refuses to be distracted by anything else. Will tomorrow's concrete bond to the concrete already here, or will it sit on a film of dust and laitance with a crack plane pre-installed. Is the seal continuous, in the plane the detail draws it in, round every corner and through every stop-end. And will the steel still be at its specified cover after the placing crew, the poker hand and the hose have been standing on it for four hours.
A joint that is not allowed to move
A construction joint is a stopping place chosen by the programme: how much concrete a crew can place and finish in a shift, how far a pump can reach, where the shutter carpenter can strike and re-set in a day. Nothing about it is a movement joint. It accommodates no shrinkage or thermal length change, carries no filler, and is detailed to behave as nearly as concrete can manage like no joint at all — full shear and moment transfer across the interface, reinforcement running straight through, and a water path deliberately interrupted. ACI 224.3R, Joints in Concrete Construction, separates the two families properly, and confusing them is how a centrebulb profile ends up cast into a wall that will never open by a millimetre.
Three independent things make that joint watertight and none of them substitutes for the others. Bond comes first: mechanical interlock across a clean, roughened interface, which is what the shear-friction provisions in ACI 318 are counting on when they allow the higher coefficient for concrete placed against hardened concrete intentionally roughened to a full amplitude of about 6 mm. A trowelled-smooth face gets the low coefficient and a capillary path along its length. The seal cast into the joint is second. The concrete either side is third — low permeability, adequate cover, and crack widths controlled by reinforcement rather than by optimism, which BS EN 1992-3 formalises through tightness classes, the crack width its usual class allows falling as the ratio of hydrostatic head to wall thickness rises, and ACI 350 through its own liquid-tightness rules. A waterstop in a badly cracked wall is a very well sealed line through a leaking panel.
A wall joint, from tomorrow's pour down to the slab mat
- The lift going in tomorrow — placed in shallow layers along the joint rather than tipped toward it, and ordered against the form volume plus the overbreak the kicker line always produces Concrete Calculator
- Dowels through the joint — the reason the joint transfers force at all, lapped at the class the drawing names and staggered so the splices do not all land in one plane Rebar Lap Splice Length Calculator (ACI 318)
- Ribbed waterstop — half its width cast into the kicker and half into the wall above, fused at every splice and turned through corners on factory fittings Waterstop Linear Footage Calculator
- Kicker and its roughened face — cut back to sound exposed aggregate rather than scoured to a sand texture, then left clean, damp and free of standing water
- Slab mat on its chairs — held off the blinding or the membrane by supports rated for the bar and spaced tightly enough that a boot between them changes nothing Rebar Chair and Bolster Count Calculator
The face you leave behind is the face you have to bond to
The top surface of any lift is the worst concrete in that lift. Bleed water rises through the placed mix carrying the finest cement and filler particles with it, and what dries on top is laitance: a weak, dusty, poorly hydrated film with almost no tensile capacity and no interest in bonding to anything. On a kicker it is a few millimetres thick, it looks like concrete, it survives a broom, and it is the single commonest reason a joint that was fully detailed and correctly sealed still shows a damp line along its length for the rest of its life.
Removing it is a timing problem before it is a technique problem. Green cutting — an air and water jet worked across the surface once the mix has stiffened enough that the coarse aggregate stays put but before it has properly hardened — is the cheapest method by a wide margin, and its window is measured in hours, moving with mix temperature, cement type and any retarder in the load. Miss it and the job becomes abrasive blasting, high-pressure water jetting or scabbling after set, all of which need access the wall cage has since taken away. On a vertical stop-end, spraying the bulkhead with a surface retarder and washing the face down the following morning gets the same result with no timing anxiety, which is why it is worth specifying on any joint that will be hard to reach later.
Aim for sound, exposed coarse aggregate at a full amplitude of roughly 6 mm, and stop the moment the stone starts to move. Over-jetting produces a face littered with loosened aggregate, which is laitance with bigger particles in it and behaves exactly the same way. ACI 301, the specification for concrete construction, is the document that requires construction joint surfaces to be clean and free of laitance before new concrete is placed, and the amplitude is what turns a clean face into a face that can carry shear.
Two products belong nowhere near a joint face. Membrane-forming curing compounds to ASTM C309 are designed to leave a bond-breaking film, which is the whole point of them and a disaster here — mask the joint if a sprayer is working anywhere near it. Form release is the same problem arriving by a different route, usually from an over-generous coating on the bulkhead. And at the pour itself the face wants to be clean, sound and damp, with no standing water: a saturated surface takes no water out of the fresh mix, whereas a puddle in the bottom of the kicker joint raises the water-cement ratio of the first hundred millimetres of the pour, precisely where the waterstop is.
- Decide the treatment before the first lift goes in, because green cutting has a window of hours and everything else needs access the cage will remove.
- Where the joint is a vertical stop-end, spray the bulkhead face with surface retarder and book the wash for the following morning.
- Cut back to sound exposed coarse aggregate, roughly 6 mm of amplitude, not to a scoured sand-textured surface that photographs as clean.
- Stop before the stone starts moving; loosened aggregate is laitance with bigger particles in it.
- Wash down and blow the arris out with air, rather than sweeping the debris into the corner where the waterstop sits.
- Lift standing water with a vacuum or a sponge immediately ahead of the placing crew, not the night before.
- Keep curing compound, form release and every other bond breaker off the face, and mask it if a sprayer is working on the same level.
Choosing the seal, then buying it by the metre
The profile cast into the joint is chosen for the joint, not for the wall. A ribbed dumbbell in PVC or rubber is the default for a construction joint under permanent head: ribs on both sides of a central web, half the width embedded in each pour, and a long tortuous path for any water that gets past the bond. A centrebulb profile is a movement-joint product — the bulb exists to deform as the joint opens — and casting one into a joint that will never open buys a void through the middle of the wall in exchange for nothing. The material specifications are worth naming in the order: the US Army Corps of Engineers CRD-C 572 covers polyvinylchloride waterstop, and the rubber equivalents are specified through the manufacturer's own literature against tensile and hardness test methods such as ASTM D412 and ASTM D2240.
Hydrophilic strips work on a different principle: a bentonite or modified-rubber section that swells on contact with water and seals by developing pressure against the concrete around it. They fix quickly and they suit congested joints and pipe penetrations where a rigid profile will not fit, and two conditions come attached that get skipped. They must not hydrate before the pour — a strip left out through a wet week swells against nothing and never recovers its density — and they need the cover their manufacturer states all round, because the same pressure that seals the joint will spall a thin edge off it. CETCO Waterstop-RX and the Sika Greenstreak Hydrotite range both publish that cover as a performance requirement, and it differs by profile, so read the sheet for what was delivered. Re-injectable hose systems such as Sika Injectoflex are a designed second chance rather than a primary seal, and they only work if the ports come out somewhere that will still be accessible.
Then buy it. Joint length adds up much faster than crews expect, because it is never just the wall. Take a box 34 by 18 m on plan: the perimeter kicker joint alone is 104 m, nine vertical day joints in a 3.6 m wall add another 32 m, and a slab poured in six bays contributes three more — two across the 18 m width and one along the 34 m — for a further 70 m. That is 206 m of joint holding water on what most people would call a small basement. Add a real waste allowance: splices consume material, every corner and tee wants a factory-moulded fitting, and cutting round starter bars wastes more than a straight-run measurement can see. Waterstop is the classic item that stops a pour at four in the afternoon, because nobody counted the corners.
| Seal | Where it belongs | What defeats it on site |
|---|---|---|
| Ribbed dumbbell, PVC or rubber | Construction joints held against permanent head | Folded flat in the pour, or spliced with tape instead of a fused weld |
| Centrebulb profile | Movement joints, where the bulb has to accommodate opening | Being bought for a construction joint, where the bulb is simply a void |
| Hydrophilic strip | Congested joints and around penetrations where a rigid profile will not fit | Hydrating in the rain before the pour, or cast with less cover than the data sheet asks |
| Re-injectable hose | Joints with no access afterwards, as a deliberate second chance | Ports buried, unlabelled or left where a follow-on trade will build over them |
| Permeability-reducing admixture | The concrete either side of the joint, never the joint by itself | Being sold to the client as the seal, which it has never been |
Total every joint that has to hold water — perimeter kicker, wall day joints, slab bay joints, returns — then carry the waste that splices, corner fittings and cutting round starters genuinely consume.
SettingsSettings for this calculation
The standard allowance most suppliers and estimating guides assume for ordinary work.
The sum of all construction/expansion joint lengths requiring a waterstop seal.
Extra material for splices, corners, and cuts.
Waterstop needed
182 linear ft
Corners and T-intersections need factory or field-fabricated waterstop fittings, which use more material than a straight run — increase the waste factor for joint layouts with many corners.
- Base joint length (no waste)
- 165 ft
They open the calculator with your figures already in it
Waterstop Linear Footage Calculator: 182 linear ft — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Estimated cost — your price
This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.
What this calculation does not cover
- This returns a length, not a specification. Waterstop width, profile — flat dumbbell, centerbulb, ribbed, hydrophilic — and material are selected from hydrostatic head, expected joint movement and chemical exposure, and none of those are inputs here.
- Prefabricated corner, tee and cross fittings are not counted. Those are ordered as individual pieces off the joint layout rather than as linear stock, and the waste percentage pads the straight run instead of producing a fitting schedule.
- The figure is a raw length, not a coil count. Waterstop ships in fixed-length rolls, and the offcuts left where a roll does not divide evenly into a joint run are not modelled — the waste factor is a flat percentage, not a per-splice or per-roll calculation.
- It does not decide which joints need a seal. You supply the total; water table depth, hydrostatic head and the project's waterproofing design determine which construction and expansion joints require waterstop, and this take-off is not a substitute for that design.
- Nothing beyond the waterstop itself is included. Hydrophilic strips, injectable hose, joint sealant, bond breakers, split formwork, and the hog rings or tie wire that hold the waterstop centred and upright during the pour are all separate items.
Fixing it so the pour cannot move it
A waterstop only works where it actually is. Half the profile has to finish up embedded in each pour, standing in the plane of the joint, and the forces trying to prevent that are considerable: a placing hose swinging across it, a poker head dragged along it, and a metre of fresh concrete arriving on one side before anything supports the other. The fixing has to win that argument on its own, because nobody is going to be looking when it is lost.
For a horizontal joint, the profile is held upright by tie wire or hog rings passed through the factory-punched eyelets and tied back to the reinforcement at the spacing the installation sheet gives — close enough that the section between two fixings cannot flop over. For a vertical stop-end, the bulkhead is split so the waterstop passes through it, which is fiddly carpentry and the reason the alternative gets improvised. Nothing is nailed through the web or a bulb: every hole is a leak with a fixing in it, and the eyelets exist so the fixing does not need one. Keep the exposed half clean as well — form oil, dried mud and concrete splatter on the projecting leg all break the bond between the profile and the second pour, which is the surface the seal depends on.
Splices are made by thermal fusion, not by overlapping. A PVC waterstop is spliced with a Teflon-coated splicing iron, the cut ends squared, melted until the material flows, held until it cools, and inspected afterwards for a continuous, void-free weld across the full section including the ribs. Rubber profiles are vulcanised or joined with factory-moulded splices. An overlapped and taped joint is not a splice; it is a bypass around the seal with tape holding it in place. Corners, tees, crosses and transitions from horizontal to vertical are bought as factory-moulded fittings and fused into the run. A field-mitred corner is the single most reliable place to find a leak in a basement wall, and it happens because a corner fitting was not ordered and a crew improvised at half past four.
Two last details for the evening walk. PVC softens in sunlight, so a run left projecting through a hot summer can distort enough to sit out of plane — check it rather than assume it. And where a service crosses near the joint, look at where the sleeve lands: a penetration in the joint plane forces a broken waterstop run and a detail somebody invents on the spot. It belongs above or below, with its own puddle flange or hydrophilic collar to the specialist's drawing.
Cover has to survive fourteen pairs of boots
The other half of the walk is the steel, and the joint zone is where cover is under most pressure because it is where everything converges: dowels, the wall cage, ties, the waterstop and often a hydrophilic strip as well. ACI 318's cover provisions ask the most of concrete cast against and permanently exposed to earth, and ACI 350 asks for more again in liquid-tight structures, because cover is what stands between a chloride and a bar and a repair on a submerged face is not one anybody wants to price. Below grade those requirements land on the two faces least able to defend themselves: the earth face, unreachable once the form closes, and the top mat, which everybody walks on.
Bar supports hold it, and they are a specified product rather than an accessory. The CRSI Manual of Standard Practice sets out the types and the protection classes: plastic-protected and stainless-protected supports near any face that will be exposed, plain wire only where it will never see moisture or view, precast blocks with cast-in tie wire where the mat sits on earth or blinding. Support height comes from the specified cover and the layer order, not from what is on the truck. Where the slab sits on a vapour retarder, supports need sand plates or wide bases — ASTM E1643 is explicit that the sheet is to be kept intact, and a chair leg is one of the standard ways it stops being intact.
Then count them, because adequate support is arithmetic on a grid rather than a judgement. Take one slab bay 18 by 12 m with a 200 mm grid top and bottom, supports rated at 1.2 m along the bar and the mat stiff enough to carry every second bar: sixteen support lines, thirty-one bars carried on each, and 992 individual chairs once both mats are counted — or 384 m of continuous bolster, which on a bay that size is usually quicker to place. The rated spacing is not something to guess at; it comes from the supplier's data or the specification, and a spacing chosen for a static check is the wrong spacing for a mat a crew will drag a hose across. Vertical faces need their own count of side-form spacers, because gravity does nothing to hold a cage back from a form face.
None of it survives without traffic management. Lay runway boards over the top mat and agree the pump hose route before the truck arrives; put a spotter behind the placing crew with a tape to lift anything that has gone down while there is still time; and cap protruding dowels, which OSHA 29 CFR 1926.701(b) requires guarded against impalement anyway and which also stops people picking a route through the cage instead of over it. This matters more than it sounds because a mat walked flat photographs as correctly placed. Nothing in the record shows the loss; it appears years later as a rust stain following a bar line, and by then the only honest answer is that the chairs were too few on one evening in August.
Put the bay dimensions, the bar grid and the support spacing your supplier actually rates into it, and take both numbers off the answer: individual chairs to order, and the equivalent run of continuous bolster if the mat would be faster to carry on runners.
The longer plan dimension of the reinforcing mat.
The plan dimension across the direction the support lines run.
Centre-to-centre spacing of the bars being supported.
How far apart the supports may sit along a bar, from your supplier's data or your specification.
Whether each bar sits on a support or the mat spans between supported bars.
Enter one for a single layer, two where a top and a bottom mat each need supporting.
The length of vertical form face where cover has to be held off the steel.
Centre-to-centre spacing of the spacers along that vertical face.
Bar supports needed
140 chairs
A count on the grid you entered. It does not judge whether the support spacing is adequate — that depends on bar size, mat stiffness and the traffic the mat will take, and it belongs to your supplier's data or your specification.
- Support lines along the mat
- 10 lines
- Bars across the mat at this spacing
- 27 bars
- Bars actually carried on each line
- 14 bars
- Chairs per mat
- 140 chairs
- Continuous bolster instead of point chairs
- 260 ft
- Side-form spacers
- 33 spacers
- Mat area supported
- 1,014 ft²
- Supports per unit of mat area
- 0.14 chairs/ft²
They open the calculator with your figures already in it
Rebar Chair and Bolster Count Calculator: 140 chairs — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Estimated cost — your price
This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.
What this calculation does not cover
- No support-spacing table is applied; the spacing is yours to supply and yours to defend.
- Chair HEIGHT is not calculated. It follows from the specified cover, the bar diameters and the layer order.
- Sand plates or larger bearing feet may be required on soft subgrade or on a vapour barrier; the count is the same, the product is not.
- Openings, thickenings and bays that break the mat need counting separately.
Supporting every second bar leaves the mat spanning between lines — fine on a stiff grid, and the reason a light mat shows a wavy cover line in the finished soffit. At 1.49 supports per square metre (0.14 per square foot), the same grid bought as continuous bolster comes to 79.2 m (260 ft) of runner, which on a large pour is usually the faster fix and often the cheaper one.
Concrete has to get under the bulb
Everything above is undone if the mix does not arrive properly around the seal. The 300 mm either side of a construction joint is the most congested concrete on the job — dowels, ties, the waterstop web, whatever the cage is doing locally — and a honeycomb void behind a correctly installed waterstop is a leak with a perfect seal running through it. Horizontal profiles in slab joints are the worse case, because air and bleed water collect under the bulb and stay there unless the placing method drives them out.
Place in shallow layers and place along the joint rather than toward it, so the concrete arrives at the profile at a controlled rate instead of surging past it. Do not drop the mix from height onto the waterstop; the coarse aggregate separates on the way down and lands as a stone pocket exactly where it does most harm. Consolidation follows ACI 309R, the guide for consolidation of concrete: the poker goes in vertically under its own weight, penetrates about 150 mm into the layer below so the two knit rather than stack, and comes out slowly enough for the hole to close behind it. Keep the head off the waterstop and off the form face — vibrating the profile directly tears it away from concrete it has already gripped.
The insertion pattern is worth setting out rather than leaving to the poker hand's judgement in the dark. The radius of action is a property of the head and the mix, published by the vibrator manufacturer, and it shortens in a stiff mix and in heavy reinforcement, which is precisely the condition at a joint. Space the insertions so their radii overlap rather than merely touch, and work out what that means in insertions per square metre before the pour, because a crew that is behind schedule consolidates on a grid it can remember, not on one it has to think about.
Take the radius of action from the head you actually have, treat the catalogue figure as an upper bound in congested steel, and turn the required overlap into a spacing and an insertion count the crew can hold at two in the morning.
The distance from the head over which the concrete is actually consolidated.
How much the circles of action are made to overlap rather than merely touch.
The thickness of concrete placed in one pass before the next layer goes on.
How far the head is driven into the previous layer to knit the two together.
Insertion spacing
14.6 in
The geometry is exact for the radius entered, and the radius is the uncertain part. Published figures assume a workable mix and open reinforcement; in congested sections the working radius falls, which tightens the spacing this calculation returns.
- Insertions needed per unit of lift area
- 0.67 points/ft²
- Overlap achieved between adjacent circles of action
- 4.87 in
- Minimum vibrating length to reach the layer below
- 22 in
- Ground consolidated by one insertion
- 1.49 ft²
They open the calculator with your figures already in it
Concrete Poker Vibrator Insertion Spacing Calculator: 14.63 in — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Add the equipment this sizes
This result is a specification — 14.6 in — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.
What this calculation does not cover
- Assumes a square insertion grid. A wall is a line of insertions rather than a grid, so use the spacing and ignore the per-area figure there.
- Says nothing about duration. Insertion spacing decides where the poker goes; how long it stays is judged from the surface levelling, bubbles ceasing and a mortar sheen appearing, and over-vibration is as damaging as under-vibration.
- Excludes form-face treatment entirely. Vibrating against formwork or reinforcement puts energy where it is not wanted and can shift bars already tied to tolerance.
The walk itself, in the order water will take it
Work upward, because the things at the bottom of a pour get buried first. Start at the slab bay joints, come up onto the kicker, follow it round every corner and into every return, then the vertical stop-ends, the penetrations, the cage, and the access arrangements over the top. Reversing the natural instinct, which is to look at eye level, is what stops the bottom 300 mm being the part nobody inspected.
Photograph as you go, with a tape in frame, and raise anything you cannot resolve tonight as an RFI dated tonight. A hold point signed at half past six the following morning under the noise of a waiting truck is not an inspection, and everybody involved knows it. The list below is the one worth carrying on a phone.
- Slab bay joints: waterstop continuous, splices fused, and the joint face cut back rather than swept.
- Kicker joint: continuous round every corner and into every return, on factory-moulded fittings, with every splice thermally fused across the full section including the ribs and no taped laps anywhere in the run.
- Profile position and fixings: standing in the plane of the joint, not folded and not sun-distorted, tied through the factory eyelets at the manufacturer's spacing, nothing nailed through the web or a bulb.
- Hydrophilic strip, where used: continuous, still dry, fixed hard against the substrate, with the cover its data sheet demands available all round.
- Steel: dowel projection and lap lengths taped at several points, splice stagger as drawn, clear spacing checked against the aggregate size.
- Cover: chairs counted against the mat area, sand plates where the mat sits on a membrane, side-form spacers on both wall faces.
- Access: runway boards over the top mat, pump hose route agreed and drawn, dowel caps on.
- Joint face: clean, sound, damp and free of standing water, with the vacuum on site for the morning rather than promised.
- Penetrations: nothing landing in the joint plane, every sleeve carrying the collar the specialist drawing shows.
- Record: photographs with a tape in frame at every corner fitting and splice, hold point signed, RFIs raised tonight.
What tomorrow cannot fix
Some of tonight's findings have a remedy in the morning and some do not, and being clear about which is which is the difference between a useful walk and a list of complaints. A laitance-covered face can be jetted at seven. A missing corner fitting can be fused in if the store has one and the pour can be held. A short lap, a mat lying on the membrane and a waterstop folded flat are all fixable before the boards close. Congestion so tight the aggregate cannot pass is not fixable tonight and never was — it is an RFI, and it wanted raising when the drawing was issued.
Once the concrete is in, the options narrow sharply. A joint that weeps can be injected — polyurethane resins for an actively water-bearing joint, where the reaction with water is the point, and epoxy where the requirement is to rebond a dormant crack rather than to chase water. ACI 224.1R is the reference for choosing between them, and the honest summary is that injection is a repair with a success rate rather than a detail with a design life. A joint built with a re-injectable hose has a genuine second chance; a joint without one has a coring rig and a hope.
Two failure modes deserve naming because neither is on any drawing. The first is the cold joint: the truck is fifty minutes late, the previous layer takes its initial set, and the wall now contains an unplanned joint with no preparation, no waterstop and no record of where it is. Continuity of supply on a below-grade pour is therefore a watertightness question, not only a programme one, and the retarder dose, the standby truck and the decision about when to stop and form a proper joint belong in the pre-pour briefing. The second is the joint nobody thought was a water joint: the lift pit poured by a different gang, the return in the corner where the drawing changed. Water finds those in the order the head presents them.
| What shows up inside | Usual cause | Cheapest moment to fix it |
|---|---|---|
| A damp line along the kicker, drying and returning with the season | Laitance left on the joint face, so the bond was never made | The morning of the pour, with a jet and a vacuum |
| A single weeping point on an otherwise dry joint | A folded profile, a taped splice, or a fixing nailed through the web | Tonight, before the second form face closes |
| A steady run at an internal corner | A field-mitred corner in place of a factory-moulded fitting | At the order, weeks ago |
| Honeycomb under the bulb, visible when the form is struck | Concrete placed at the joint faster than it was consolidated | During the pour, and only during the pour |
| Rust staining following a bar line two winters later | The mat walked down, cover lost, or plain wire supports at an exposed face | Tonight, with chairs, bolsters and a runway board |
Settle these before the bulkhead closes
Six numbers that decide whether tomorrow's joint holds water, all of them cheaper to argue about with a torch in your hand than with a coring rig in a finished basement.
- Joint length that has to hold water — Perimeter kicker, wall day joints, slab bay joints and every return — taken off the drawing, not off the wall length.
- Corner, tee and transition fittings — Counted individually and ordered as factory-moulded pieces; this is the line item that stops a pour at four in the afternoon.
- Waste allowance on the waterstop — Splices, cutting round starter bars and offcuts at fittings consume material a straight-run measurement cannot see.
- Rated support spacing for the mat — From the bar-support supplier's data or the specification, chosen for a mat that will be walked on rather than for a static check.
- Chair and bolster count per bay — Support lines times supported bars, times the number of mats, plus side-form spacers on every vertical face.
- Insertion spacing for the poker — Radius of action for the head you have, derated for congestion at the joint, converted into a grid the crew can hold at night.
Opens the calculators above on one screen with the dimensions from this article already filled in. Quantities only — this site publishes no price list, because local prices vary too much to publish honestly.