A screeding quote is really three estimates in one: materials, labour, and the preparation nobody prices until it becomes a variation claim. Comparing quotes without separating these three lines is how a "cheap" job finishes 60% over.
This guide builds a complete screeding cost estimate for real market conditions: current cement and sand pricing per square metre, labour rates by engagement model (daily wage versus per-square-metre), preparation costs that quotes omit, and a comparison framework for evaluating contractor numbers against your own. The arithmetic is simple; the savings come from knowing what to ask.
The Three Lines: Why Screeding Prices Are Three Different Numbers
Materials scale with area, thickness, and mix (the quantities guide computes them per wall). They are knowable in advance to within the waste factor, which makes material under-estimation a choice, not a misfortune.
Labour scales with area, condition, and the crew's model, and unlike materials, its rate varies by a factor of two across engagement models for the same wall.
Preparation scales with what the assessment finds, and it is the line quotes skip, because it is unknowable until the wall is read. Every unpriced prep hour returns as a "variation" at quote-plus rates.
A screeding estimate that cannot name all three separately is not an estimate; it is a mood. And the comparisons that go wrong go wrong there: the cheapest quote is usually the one that omitted the same preparation the expensive quote priced.
Line 1: Materials, Priced Per Square Metre
The material cost per m² follows one honest chain (run it yourself with the screed calculator or by hand): area × thickness → wet volume → ratio → bags and sand → waste-adjusted, then priced at delivered rates.
The worked shape per m², at a standard single coat of 8 mm at 1:4: wet volume ≈ 8 litres; dry-adjusted ≈ 10 litres; cement ≈ 0.06 bag/m² (order-rounded per job, not per metre); sand ≈ 0.008 m³/m², roughly a full trip of sand per 120–150 m² of wall. At a 12 mm levelling coat, the numbers scale to roughly 0.09 bag/m² and proportionally more sand; a finishing pass at 1:3 on top adds its own, richer bag line.
Pricing honesty: price cement at the delivered rate (depot price + transport, the "cheap bag" at the far market is a transport bill wearing a discount), sand per trip shared honestly across the job, and add the line the arithmetic always forgets: water for the cure, the 5–7 day misting regime is a real, if small, water cost on sites without a tap. Bonding agent, where the assessment calls for one (the bonding guide), is a priced line, not a surprise, and on smooth-wall campaigns it is one of the larger ones.
The calibration number to hold: materials are typically the smaller of the two big lines, labour, at screeding's skilled rate, generally out-prices cement and sand on most jobs. Any quote that is 80% materials has priced its labour somewhere else.
Line 2: Labour, by Engagement Model
Two models dominate, with different honest economics:
Per-m² (piece rate): the market standard for screeding, quoted per square metre of finished wall. Its honesty depends on the scope sentence: does the rate include preparation, staffs, and the cure, or only the trowel day? A per-m² rate plus a separate prep day is the truthful structure on walls that need work; the all-in per-m² rate on a wall nobody has read is a wager.
Daily wage: paid for attendance, not output, the honest model for unpredictable or repair-heavy work, and the dishonest one for repetitive large areas, where it quietly prices the same wall at double the per-m² market. The daily rate's second cost is the idle day: a crew waiting on materials or decisions is a wage line with no output line.
The professional structure most owners land on: per-m² for the measurable body of the work, daily or itemized for the preparation, and a payment gate at acceptance (the five checks in the complete guide), money follows a torch-and-tap-tested wall, not a handover conversation.
Line 3: Preparation, the Line That Becomes a Variation
Bonding materials + labour, priced per m² of treated face
Deviations >10 mm
Levelling passes + staffs campaign
Extra material volume + skilled labour, priced per wall
Damp/moist walls
Drying window, cause fixed first
Calendar cost; can idle the schedule
The professional move is pricing preparation after the assessment and before the quote is signed, the two-hour reading of the walls converts the variation-claim ambush into a written line. Quotes that skip the assessment entirely are not cheaper; they are unpriced, and the difference arrives as a claim at the worst possible negotiating moment (mid-wall, crew on site).
Building the Estimate: a Worked Room
A 3.6 m × 3.0 m bedroom, four walls, two openings, fair blockwork needing one 8 mm screed coat at 1:4:
Net area: ~38 m² (measured per wall, openings deducted)
Materials: ~2.3 bags → 3 delivered, sand ~0.3 trip shared, cure water, no bonding agent (open blockwork), priced at today's delivered rates, the room's materials are a modest line, dominated by the cement and the trip share.
Labour: 38 m² at the market's per-m² screeding rate, at typical rates, this is the room's biggest single line, commonly 1.5–2× the materials.
Preparation: assessment finds one drummy patch (0.4 m²) and standard suction, a half-day prep item for the patch plus washing/dampening; priced itemized rather than folded silently anywhere.
The total is then three clean numbers the owner can check against any quote, and the acceptance gate holds the last tranche.
Scale the same structure to the flat: measure per room, sum per line, add the waste once at the end, price at delivered rates, and the estimate lands within the honest band (±15% is realistic; ±0% is not a feature of estimating anywhere).
Comparing Quotes: the Framework
With your own three lines built, quotes become comparable:
Line-match, not total-match. Does the quote name materials, labour, and prep separately? A total without lines cannot be compared, only hoped.
Check the material line against your arithmetic (the quantities guide). Over-listed materials = padding or a thicker coat than discussed; under-listed = the shortfall arrives mid-job.
Interrogate the labour model: per-m² including prep, or per-m² plus prep days? The daily-wage quote needs its idle-day risk priced, by you, since no one else will.
Find the assessment. A quote without a wall-reading has not priced the prep; treat the difference as a claim you will receive later.
Fix the acceptance gate: payment schedule tied to the five checks, retention through the first season for exterior work. The cheapest quote without a gate is the most expensive job in the building's ledger.
The 60%-over quote from the intro is always this story: a cheaper total that omitted prep, priced labour for half the walls, and held no gate, while the "expensive" quote had read the same walls and written the same three lines you now know how to build.
The Calendar Cost: Time Is a Line Item
Two time costs recur in every screeding job and appear in almost no quote:
The cure window. The 3–7 day damp cure (the curing guide) is days in which the wall is tended but not worked, and on a multi-room job it is also days the next room is not starting (crew economics) or is starting (room-by-room sequencing, the honest solution, and the reason rooms finish in waves rather than all at once). The cure is not optional labour-and-water time; skipping it converts to the redo budget.
The paint wait. The polythene-verified drying window after the cure is more calendar, and the painter who starts early is borrowing from the paint budget at compound interest. The estimate that schedules this honestly (room A cures while room B is coated, painter follows two rooms behind the screeder) costs nothing extra; the estimate that pretends all rooms finish together pays idle crew days on one side and trapped moisture on the other.
Priced or not, these windows are real, the difference between the quote that names them and the quote that ignores them is rarely the money; it is whether the schedule that comes with the job is a plan or a wish.
Negotiation in Practice: the Ten Minutes That Save the Margin
With your three lines built, the site negotiation compresses into three questions the tradesman will recognise as professional:
"What does the per-m² include?", prep, staffs, and cure included makes an all-in rate honest; excluded makes the prep line the negotiation, and it is cheaper negotiated before the wall is half-coated.
"Which walls took the assessment?", the answer maps directly onto your prep line; a tradesman who has read the walls quotes with their names, not with a shrug.
"What are the acceptance checks and the payment gates?", the five checks named in the quote (the complete guide) and the payment split behind them is the difference between a rate and a relationship: the screeder who agrees to a torch-and-tap gate before payment is a screeder whose work survives the gate.
The savings in this guide are not aggressive-negotiation savings; they are information savings, the quote that meets an owner holding three honest lines is a quote written carefully, and the careful quote is the cheap one in every currency.
Conclusion
Screeding costs are three honest numbers, materials from the quantities chain at delivered rates, labour by engagement model with the idle days priced, preparation from a written assessment, summed once, gated at acceptance, and compared line-by-line against every quote that wants the job. Build your own three lines first; the comparison then takes ten minutes and saves the margin on every wall you ever commission.