Variation orders in interior work, priced from the BOQ

What a variation order is

Once a client accepts a quotation built on a BOQ, every later change is a variation: an extra item, a line dropped, a material swapped, a quantity that grew on site. A variation order writes that change down with its price and its effect on time before the work is done, so the final bill is the BOQ plus a short list of approved changes, not an argument.

In interior work most variations are substitutions (veneer instead of laminate, a different tile), additions (a loft nobody drew) and quantities that move once walls are measured.

The model: CPWD's clause 12

Private interior contracts aren't bound by government rules, but the Central Public Works Department's General Conditions of Contract give a tested structure for changes. Clause 12 says, in short:

• Changes are made in writing. The engineer in charge may alter, omit, add or substitute work by a signed written instruction, and the changed work becomes part of the contract.
• A changed item keeps its contract price. Altered or substituted work is done on the same conditions, including price, as the main work, unless the rules below apply.
• A new item gets a market rate, claimed quickly. For an item not in the contract, the contractor claims a market rate within 15 days, backed by a rate analysis and invoices; the engineer decides the rate within 45 days.
• Quantities far above the BOQ can be re-rated. Where a contract item exceeds the limit set in the contract's schedule, the rate for the excess quantity can be revised the same way.
• Time moves with cost. The completion time is extended in proportion to the added cost against the original contract value, plus 25% of that extra time.

What to write on a variation order

1. Which line it changes: the BOQ line number and its description, or "new item".
2. What changes: added, omitted, substituted or quantity revised, with the new description written as fully as a BOQ line (board and grade, thickness, finish, hardware, unit and measurement basis).
3. The rate and where it comes from: the BOQ rate if the item is already in the BOQ; a new rate with its rate analysis if it isn't.
4. The amount, plus or minus, and GST on it.
5. Effect on time: the extra days, worked out the same way as clause 12 or as agreed.
6. Effect on payment: which payment stage it is billed with.
7. Signatures and date, before the work starts.

Pricing a change from the BOQ

Most of the price is already in the BOQ. A wardrobe that grows from 60 to 72 sq ft by front elevation is 12 more sq ft at the agreed rate. A swap from laminate to veneer shutters is the difference between two rates, each built from material, labour and wastage. An omission is a credit at the BOQ rate.

This only works if the BOQ line said what was priced. "Wardrobe, per sq ft" gives nothing to price a change against; a line that names the board, thickness, finish, hardware and measurement basis does. The measurement rules and material specifications are where those lines are settled.

Agree the rules before the first change

Put the variation rules in the quotation's terms: changes only in writing, the BOQ rate for listed items, how a new item is priced, and how much quantity can grow before its rate is reopened. Ahrom Labs' own default terms for a design studio's quotations include "work not listed here, or changed after acceptance, is quoted separately as a variation".

Boundary

The clause 12 summary is from the CPWD General Conditions of Contract for construction works, April 2026 edition; it binds government works under that contract, not a private interior job. Use it as a model and put your own rules in your contract. The schedule limits it refers to vary by contract and are not given here.

Quoted from the official text (3) ›

“shall be carried out by the contractor on the same conditions in all respects including price on which he agreed to do the main work except as hereafter provided”

CPWD General Conditions of Contract (April 2026), clause 12

“within fifteen days of the receipt of order or occurrence of the item(s), submit claim for market rate(s), supported with proper analysis of rate”

CPWD General Conditions of Contract (April 2026), clause 12.2

“25% of the time calculated in (i) above or such further additional time as may be considered reasonable by the Engineer-in-Charge”

CPWD General Conditions of Contract (April 2026), clause 12.1(ii)