A building variation is a change to the work described in the contract: something added, removed or altered after the contract is signed. Variations come from a small number of sources. Some can be narrowed before signing, some cannot, and knowing which is which is the practical way to keep their number down.
What a variation is
The contract describes a particular house: the drawings, the specification, the selections and the price. A variation is any change to that description once the contract is in place. It can add work, remove work or change how something is built or finished.
Each variation can change two things: the price and the programme. A variation that looks small on paper can still affect the order of work if it touches something other trades depend on.
A variation on its own is not a sign that something has gone wrong. A house is designed and priced before it exists, and some decisions and discoveries can only happen once it is under way. The aim is a contract in which each change is handled the same way, in writing.
Changes the owner asks for
One familiar source is a change of mind. A different benchtop, an extra power point, a window moved, a room reconfigured. Each is a reasonable request, and each is still a change to what was priced.
Timing matters as much as the change itself. A change made before the relevant work starts is usually easier to price and sequence. A change made after related work is built may also involve rework.
Before asking for a change, it helps to ask what it touches: which trades, which work already built, which items already ordered. The answer is where the price of the change comes from.
Changes that remove work can still carry a cost if materials have already been ordered or work has to be taken out. Writing down the reason for each change, with its price and its effect on the programme, also helps later: at handover, the variation record explains why the finished house differs from the original drawings.
Selections left open at signing
Where a selection has not been made when the contract is signed, the quote carries an allowance for it, often as a prime cost item. When the actual selection is made, the allowance is replaced by the real figure, and the difference becomes an adjustment.
The more selections that are settled before signing, the fewer allowances the contract carries, and the fewer adjustments later. Selections that genuinely cannot be made yet are better listed with a realistic allowance than left vague.
Some selections affect work well before the item itself is installed. A freestanding bath may need its waste location resolved before the slab is poured or the floor is laid. A wall-mounted tap needs its fittings in the wall before the wall is lined. An appliance may need its own circuit. Choosing late can mean changing work that has already been built.
A selections schedule that shows when each choice is needed, set against the build programme, makes late choices visible before they turn into variations.
What the site reveals
Some conditions cannot be known until the work reaches them: rock, old footings, buried services, fill, or ground that differs from what the soil investigation found at its test locations. These are latent site conditions.
They can only be priced once they are found. What can be done in advance is investigation, a soil report and a survey, plus a contract that says what counts as such a condition and how it will be priced and agreed when one appears.
A provisional sum in the quote is one way of acknowledging this in advance. It sets aside an allowance for work whose extent is not yet known, and the actual figure replaces it once the work is done.
On a knockdown rebuild, the previous building adds its own category of unknowns: old footings, a buried slab, backfilled service trenches. On vacant land, the questions centre on what the ground is made of and how it varies across the block.
Requirements that arrive during the build
A requirement from an authority, a utility or a network operator can change the work after the contract is signed. These usually sit outside both the owner’s and the builder’s control, and they are priced once the requirement is known.
Gaps in the documents are a related source. Where the drawings, engineering and specification do not agree, or a detail is missing, resolving it on site can become a variation. A coordinated documentation set before signing narrows that.
Ask how a requirement that arrives during the build is handled: who tells the owner, how it is priced, and what happens to the programme while it is resolved.
Design development after signing is a similar case. If engineering is refined after the contract is priced, a change to a footing or a beam flows through to the work and the price. Settling the engineering before the contract is signed narrows this source as well.
How to keep variations to a minimum
Settle as many selections as possible before signing. Make sure the quote is priced from the final drawings. Have the site investigated. Read the exclusions and the allowances, and ask what each one assumes.
When a variation does arise, ask for it in writing before the work proceeds: what is changing, the price, and any effect on the programme. Keep each one with the contract documents, so the record of the build stays in one place.
Then read the variations clause in the draft contract. It is the document that sets how a variation is requested, priced and agreed on that build. At Cyberidge, variations are priced and approved in writing before the work proceeds.
Some variations reduce the price rather than increase it, for example when an item is taken out of the scope. They go through the same process, so the contract sum can be traced from the original quote to the final figure.
Common Questions
How can I avoid building variations?
Not all of them can be avoided, but many can be narrowed before signing: settle selections early, make sure the quote is priced from final drawings, have the site investigated, and read the allowances, exclusions and variations clause in the draft contract.
What is a building variation?
A change to the work described in the building contract after it is signed: work added, removed or altered. A variation can change the price, the programme or both.
Why do variations happen on a build?
They come from owner-requested changes, selections left open at signing, site conditions found once work starts, requirements from authorities or utilities, and gaps between the drawings, engineering and specification.
Where are variations dealt with in a building contract?
In the contract’s variations clause, which sets out how a variation is requested, priced and agreed for that build. Read it before signing and check that it matches what the builder has described.
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