You know how to do the work.
ConstructQS helps you work out what to charge.

Groundworks are where estimates most often go wrong, because so much of the cost is hidden below the surface and outside the drawings. A disciplined estimate starts with the site itself: the existing ground levels, the finished levels, the soil type, and the water table. Get those wrong and every quantity that follows is wrong too.

Begin with the topsoil strip and stockpile, priced by area and depth, and decide early whether that material stays on site or is carted away. Then work out your cut-and-fill balance — the volume you dig out that can be re-used as engineered fill elsewhere on the plot. Material you can re-use is material you neither pay to remove nor pay to import, so an accurate balance is the single biggest lever on a groundworks price. Remember to apply a bulking factor for excavated material (it takes up more space once dug) and a compaction factor for fill (it is compacted back down in layers).

From there, allow for the items that rarely appear on a drawing but always appear on site: dewatering where groundwater is high, temporary works and trench support, working space around foundations, and disposal of surplus. Muck-away should be priced by the tonne and by the lorry load, and you must check soil classification and contamination testing before you assume clean disposal — contaminated spoil can cost several times more to remove and is a classic budget-buster. Finally, add imported fill (for example 6F2 or Type 1) wherever cut and fill do not balance, priced delivered and compacted. Build all of this into a clear earthworks section so nothing is quietly absorbed into a lump sum you cannot defend later.

Four adjustments turn a direct cost into a tender figure, and understanding what each covers keeps your pricing honest and your margin protected. Confusing them is one of the most common reasons estimates end up either uncompetitive or unprofitable.

Preliminaries are the cost of running this particular job, regardless of the trades involved: site supervision and management, welfare and cabins, temporary services, scaffolding and access, plant that stands on site, insurances specific to the contract, and setting-up and clearing-away. Prelims are project-specific, so they scale with the size and duration of the job, not with the value of the work. Overheads are different — they are the cost of running your business, spread fairly across all your jobs: office, accounts, vehicles, marketing, and your own time when you are not on the tools. These are usually recovered as a percentage.

Contingency is your allowance for the unknowns on this job — ground risk, design that is not fully developed, weather, or items that cannot yet be measured. It is not padding; it is a considered figure that reflects how much risk you are carrying. A well-surveyed refurbishment might justify a small contingency, while a groundworks package on an unknown site justifies more. Profit is your margin, applied last, and it is what the business runs on. In ConstructQS each of these is a percentage you control, applied in sequence to the direct cost, so you can see exactly how a build-up becomes the final tender and adjust any one lever without losing sight of the others.

VAT is one of the most misunderstood parts of construction pricing, and getting it wrong can quietly erode a margin or land you with an unexpected bill. The UK standard rate is 20%, and ConstructQS applies it automatically for UK projects. For the Republic of Ireland, get in touch and we will confirm the current rate for your work — and the complications sit underneath the headline figure anyway.

In the UK, some work qualifies for reduced or zero rates — new-build residential, certain conversions, and energy-saving measures among them — and the rules are specific and evidence-based. On top of that, the domestic reverse charge applies to many business-to-business construction services: instead of the subcontractor charging VAT, the main contractor accounts for it. That changes cash flow and how invoices are worded, and it catches a lot of firms out. In the Republic of Ireland, the equivalent is Relevant Contracts Tax (RCT) together with a VAT reverse charge on many principal-to-subcontractor transactions, so the principal contractor accounts for the VAT rather than the subcontractor.

The practical takeaways are simple. Always price the net figure and let VAT be added correctly at checkout or on the invoice, rather than burying it in a rate. Establish early whether a job is standard-rated, reduced, zero-rated, or subject to a reverse charge, because it affects both your quote and your paperwork. Keep clean invoice and VAT records — you are legally required to retain them. And treat this article as general information, not tax advice: construction VAT is genuinely complex and changes over time, so confirm the treatment of each contract with your accountant before you rely on it.

Cut and fill is the art of reshaping a site by moving material from the high points (cut) to the low points (fill) to reach the finished levels shown on the drawings. Done well, it is invisible; done badly, it is one of the fastest ways to lose money on a groundworks package.

The goal is balance. If the volume you cut equals the volume you need as fill, you avoid paying twice — once to cart away surplus, and again to import replacement material. In practice a perfect balance is rare, so the estimate needs to quantify the shortfall or surplus precisely. Two factors always apply. A bulking factor reflects that soil expands once excavated: a cubic metre in the ground becomes noticeably more than a cubic metre in a lorry, which matters for disposal volumes and load counts. A compaction factor reflects the opposite on the fill side: material placed and compacted in layers takes up less space than its loose volume, so you need more loose material than the void suggests.

Beyond the raw balance, allow for the quality of the material. Not everything you dig out is suitable as engineered fill — topsoil, soft spots and contaminated ground are not, and must be removed and replaced with imported fill to specification. Factor in compaction plant and the labour to place fill in layers, testing where the specification demands it, and any dewatering needed to work in wet ground. A clear cut-and-fill calculation, with its factors stated, lets you defend the disposal and import quantities to a client or QS and stops two of the biggest groundworks costs from hiding inside a single lump sum.

A bill of quantities (BoQ) is a structured list of the measured work in a project, broken down so that every item can be priced, compared and checked. It turns a set of drawings into a document that both you and the client can reason about, and it is the backbone of a fair, transparent tender.

Start by organising the work into logical sections — by trade, by element, or by work package — so a large job stays readable. Under each section, each item needs a clear description, a unit of measurement, and a quantity taken off the drawings. Units matter: excavation in cubic metres, blockwork in square metres, kerbs and drainage in linear metres, and one-off items as a number or an item. Consistent units are what let you apply a rate cleanly and check a total at a glance. Measure carefully and note your assumptions, because the person pricing the bill — possibly you, months later — needs to know exactly what each line includes.

Once the quantities are measured, apply a rate to each line. A good BoQ keeps the measured quantity and the rate separate, so if the design changes you re-measure the quantity without rebuilding the whole price. It also makes tender comparison honest: when several contractors price the same bill, differences show up line by line rather than hiding inside a single lump sum. ConstructQS builds the BoQ straight from your estimate, so quantities, rates and sections stay linked, and the finished bill exports as a clean, branded document you can issue to a client or send out to subcontractors for pricing.

Behind every unit rate is a build-up, and the firms that win work profitably are the ones that build their rates from first principles rather than guessing. A rate is simply the cost of the labour, plant and materials needed to complete one unit of work, plus the allowances that turn cost into price.

Start with labour. Take the gang and the output — how much of this item the gang completes in an hour or a day — and divide the gang cost by that output to get a labour cost per unit. Crucially, use the all-in labour cost, not the bare wage: add employer’s National Insurance, holiday pay, pension, and any training levy such as CITB, plus non-productive time. Underpricing labour on-costs is one of the most common estimating mistakes. Next, plant: whether owned or hired, work out the cost for the time the item needs, including fuel, an operator if required, and mobilisation. Then materials: take the net quantity, add a wastage allowance appropriate to the material and the workmanship, and price it delivered to site rather than ex-works.

Add those three together and you have a direct rate for the item. Keep the components visible so you can see what is driving the price and adjust the one that matters — a tight programme pushes labour and plant, a volatile market pushes materials. Save your build-ups in a rate book and reuse them, tuned by region, so the next estimate starts from real numbers rather than a blank page. In ConstructQS every rate carries its source — your own rate, a supplier quote, a regional rate book, or an AI estimate — so you always know exactly what your tender is built on.

Most estimates are lost not on the rates but on the gaps — the items that never made it into the price at all. A competitive rate on 95% of the work still loses money if the missing 5% has to be absorbed. The good news is that omissions tend to fall into predictable categories, so a checklist catches most of them.

The usual suspects are the things that support the work rather than being the work: waste disposal and muck-away, plant transport and mobilisation, survey and setting-out, temporary works and access, welfare and site set-up, testing and commissioning, and reinstatement and clean-up at the end. Drainage is frequently missed as a distinct item, as are builder’s work in connection with other trades and main-contractor attendances on subcontractors. On groundworks specifically, watch for topsoil strip, compaction in layers, dewatering, imported fill where cut and fill do not balance, and soil testing before disposal. On public-sector and larger jobs, add bonds, insurances, retention and any social-value requirements.

The discipline that prevents omissions is a structured review before the price goes out. Read the estimate against a standard checklist, then read it against the specific job — what does this site, this client and this programme demand that a generic checklist would not? ConstructQS builds this in: its AI QS assistant reviews an estimate for common omissions, and it is aware of the project type and of any earthworks in the job, so it flags the items that genuinely tend to be forgotten. A two-minute review is far cheaper than discovering the gap on site.

Winning the job is only half the battle; getting paid the right amount, on time, for what you actually build is the other half. Two processes govern that: variations and valuations. Handle them well and cash flow stays healthy; handle them loosely and profit leaks away quietly.

A variation is any change to the agreed scope — extra work, omitted work, or a change in specification. The single most important habit is to price and record variations as they arise, in writing, and to get them agreed before proceeding wherever possible. Work done on a nod and priced at the final account is work you may struggle to recover in full. Keep each variation as a distinct, dated item with its own value and status, so the contract sum is always the original plus the running total of approved changes, and there are no surprises at the end.

Interim valuations are how you get paid during the job rather than only at the end. At agreed intervals you value the work completed to date — measured work, materials on site, and approved variations — and apply for payment, less any retention and previous payments. Accurate interim valuations keep money coming in to fund wages and materials, and they surface problems early: if the value of work done is drifting away from the cost of doing it, you want to know in month two, not at the final account. ConstructQS tracks approved variations, interim valuations and the final account against the original estimate, so the commercial picture of the job stays current as it runs.

Concrete looks simple to price — volume times a rate — but the volume is the smallest part of the cost. The work around the concrete, and the reinforcement within it, is where accuracy is won or lost.

Start with the net volume from the drawings, then decide how the concrete is supplied: ready-mixed and delivered, or site-mixed from bags and aggregate. Ready-mix is priced per cubic metre delivered, with part-load and waiting-time charges that are easy to overlook on small or awkward pours. Add a realistic wastage allowance — over-dig, spillage and over-order — because you cannot pour exactly the theoretical volume. Then price the operations that make the pour possible: excavation and blinding, formwork or shuttering measured by contact area, and the labour to place, vibrate, level and cure the concrete. Pumping should be a separate allowance wherever access is tight.

For reinforced concrete, the steel is a major cost in its own right. Reinforcement is priced by weight, so take off the bar schedule and convert to tonnes, then add cutting, bending, fixing labour and tying wire, plus spacers and chairs. Mesh is priced by area with laps allowed. Keep reinforcement as its own measured item rather than folding it into the concrete rate, because the two move independently — steel prices are volatile, and the reinforcement content varies hugely between a domestic slab and a structural raft. ConstructQS includes a concrete calculator for volume, weight and bag equivalents, and lets you build reinforced concrete as separate, visible items so each part of the cost can be checked and defended.

The lowest price does not always win the job, and it rarely wins the right job. Good tender strategy is about pricing to win the work you actually want, at a margin that keeps the business healthy, while carrying the right amount of risk. That is a commercial decision as much as a technical one.

Start from an accurate, honest build-up — you cannot make a sensible strategic decision on top of a wrong number. Once the cost is solid, think about margin in the context of the job. A repeat client, a job that fits your gang and plant perfectly, and a quiet period in the diary might justify a leaner margin to secure turnover. A one-off, an awkward site, a demanding client or a busy period justify more, both for profit and for the risk you are carrying. Margin is not a fixed percentage you stamp on everything; it is a lever you set job by job.

Risk deserves the same deliberate treatment. Ground conditions, design that is not fully developed, long programmes and volatile material prices all add risk, and that belongs in your contingency, in your assumptions and exclusions, and sometimes in a conversation with the client rather than silently in a rate. Be explicit about what your price does and does not include — clear exclusions protect your margin far better than a padded rate. Finally, review the whole tender before it goes out: is the margin thin enough to worry about, are the omissions covered, does the price reflect the risk? ConstructQS flags thin margins, quantifies the savings available from your own figures, and helps you draft clear exclusions — so the number you submit is one you can stand behind and still profit from.

Yes. Start from the built-in rates, then replace them with your own labour, plant, supplier and subcontract prices. Your rates always take priority.

Yes — whole-project estimating covers site works, substructure, superstructure, M&E, external works, preliminaries, overheads, profit and margin, not just single trades.

Yes. Upload PDF drawings and use the AI QS Assistant to help identify scope, quantities and possible omissions. It supports pricing — it doesn’t replace CAD or an architect.

No — it’s a tool for the people who price construction. The AI is a second set of eyes; you stay in control and approve every figure.

Yes. Turn an approved estimate into a branded, customer-ready PDF quotation or bill of quantities.

Yes — ConstructQS runs in any browser on desktop, tablet and mobile, and syncs across your devices.

Yes. Price in pounds or euros with UK or Republic of Ireland VAT handling.

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