Pricing Blocks for Tender Contracts Without Losing the Job: Building the Cost Behind the Bid

Pricing blocks for tender contracts is a cost exercise, not a guess. Before you write a figure on a bid form, build the cost per block from seven lines: cement, aggregate, labour, power, waste and breakage, mould and pallet amortisation, and delivery. Each line responds to something you can measure or ask about, and their sum is the floor under your bid. A tender priced without one of those lines usually wins the job and loses the money.

Two plants can run the same machine and still carry different costs per block, because cement price at the gate, crew size, shift length, breakage and haul distance are local numbers. That is also why a bid copied from another project is dangerous: the structure of the cost travels, the values do not.

What has to go into a cost per block?

Material is the largest group. In a hollow block mix, cement usually carries about 45 to 70 percent of the material cost, while sand, crushed stone or processed rubble take the rest, and all of them are bought by the tonne at your gate. Compare a 1:6 mix with a 1:8 mix on the same aggregate: the leaner mix saves cement but can force a longer curing period or a lower strength class, so the saving has to be tested rather than assumed.

On top of material sit labour, power, water, waste and amortisation. On a semi automatic line, labour commonly lands between 8 and 15 percent of the cost per block, and it falls per piece as output rises. Take those shares from a real trial run and keep them in a sheet you update when a price changes, not when a tender arrives.

Add the pieces you cannot sell as well: breakage at the press and in the yard often runs 2 to 5 percent, and a mix that is too wet or too dry adds to it. Those pieces were paid for in cement, labour and power, and nobody pays you back for them.

Why does cement dominate a bid and a negotiation?

Cement is the line that moves fastest and hurts most, because a small change in price per tonne lands on every block you ship. A hollow block mix commonly holds between 150 and 300 kg of cement per cubic metre of concrete, so a tenth on the tonne price lifts the material cost of that cubic metre with it.

For that reason the bid needs two things: a mix design proven by cube tests at 7, 14 and 28 days, and a written line on how cement price movement is handled between bid and delivery. Ask the buyer how their contract treats it. The answer tells you whether the tender is workable at the number you are about to write.

Compare a fixed price for six months with a price tied to the delivered cement cost: the second protects you, but it reads as a higher number on the bid form. Show the basis inside the quotation so the buyer compares like with like instead of rejecting the number outright.

How do labour, power and water change the cost per block?

Power is the next surprise. A QST6-15 installs 34.4 kW and runs on roughly 30 kW at site, while a QST1800 installs 104 kW and delivers 280 kN of vibration force for high output blocks and pavers. On a weak grid, generator fuel per hour belongs in the cost sheet. On a stable grid it is a smaller line, but the connection, cabling and protection still cost money.

Water and compressed air look like small lines until the yard runs dry or the air system leaks. Measure water per shift and carry the losses in the sheet. A leaking manifold costs more across a season than the repair would have.

Site voltage and frequency decide the drive configuration, so send them to your supplier early instead of quoting around an assumption. A quote built on the wrong supply is a quote that has to be rebuilt after the machines are ordered.

Which hidden costs sink a block tender quietly?

Pallets and moulds come first. A pallet of 1,350 x 880 x 25 mm on one machine class and 1,400 x 1,400 x 30 mm on a larger one has a replacement cost and a life counted in cycles. Divide that life into the pieces it carries and you get a real cost per block that most bid sheets never show. Moulds wear at the edges, and a worn mould shows up as a block that fails a dimensional check.

Delivery is second, and it is usually underpriced on heavy wall products. Blocks are bulky per tonne, so a truck fills by volume before it reaches its weight limit. Work out the load factor for each truck type you use, then quote per cubic metre delivered rather than per piece picked up.

Third is standing time. A crane blocked by a broken pallet, a mixer waiting on cement, a crew waiting for a truck: all of it lands in the cost per block even though no line on the bid form mentions it. Estimate those hours from last month, not from a good week.

How do you convert a block price into a price per cubic metre?

Work from geometry, then add waste. A hollow block of 400 x 200 x 200 mm occupies 0.016 cubic metres, so one cubic metre of wall holds about 62 of them before you allow for joints and breakage. In a wall 200 mm thick, one square metre of face equals 0.2 cubic metres of masonry, which is about 12 blocks. Add 3 to 5 percent for cutting and breakage, then multiply by your cost per block.

Tenders often measure wall area or masonry volume rather than pieces, so state the basis you priced: ex works per piece, delivered per cubic metre, or per square metre of a stated wall thickness. If the bill of quantities uses a different basis, convert before you compare, and write in the quotation which basis you used.

Watch the joint as well. A wall built with 10 mm joints takes slightly fewer blocks per square metre than the plain geometry suggests, but the mortar adds its own cost, so price both sides of that trade instead of one.

What should a block quotation for a project state in writing?

A quotation that survives a tender review states: the unit basis and the currency, whether the price is ex works or delivered and to which point, quantity tiers and how they are calculated, the validity period, the treatment of cement price movement, who takes and tests samples, the packing or pallet arrangement, and the payment milestones. Every item on that list is a place where a bid can be read in two ways.

Then close with what you need from the buyer. Send the quantity breakdown, the delivery point and discharge port, the site voltage and frequency, the product list with dimensions, and the curing and handling conditions you expect on site. With that in one message we can confirm the configuration, the document set and the commercial basis alongside the quotation.