Extra work is construction work that was not included in the original scope or quotation and may change the project cost, programme or method. It is not always evidence of poor practice. Without a written proposal and technical review, however, it can become a major source of budget drift.
If you are building or renovating in Portugal, this guide explains why extra work arises, how to distinguish legitimate unforeseen conditions from weak planning and what information an owner should receive before approving an additional cost.
What counts as extra work in construction?
Extra work, often discussed in Portugal as trabalhos a mais, is an intervention proposed after the original budget has been accepted. It may involve labour, materials, technical correction, a change requested by the owner or a task that was not clearly included in the contractor’s proposal.
Common examples include:
- replacing old pipework discovered after demolition;
- strengthening an area after the existing structure is exposed;
- treating concealed moisture or water ingress;
- changing a material selected by the owner;
- adding electrical outlets or lighting points;
- correcting work that does not meet the agreed requirement;
- adding finishes omitted from the original quotation;
- extending work because the initial scope did not define the limits clearly.
Renovation projects can reveal conditions that no reasonable visual survey could fully confirm before opening the building. Extra work may therefore be necessary. The problem begins when work proceeds without a precise description, agreed price, programme effect and written owner approval.
The practical rule is simple: if a proposal changes cost, programme or scope, it should be approved in writing before execution.
Why does extra work arise?
Several causes are possible. Understanding the cause helps the owner decide whether the work is necessary, whether the proposal is complete and where responsibility may sit.
1. Genuine unforeseen conditions in an existing building
Some conditions become visible only after walls, floors, ceilings or finishes are opened. Deteriorated pipework, concealed moisture, outdated electrical installations or defects in existing construction may not have been accessible before work began.
The discovery should be recorded before the area changes further. Dated photographs, location, technical comment and a description of the proposed response allow the owner to understand what has been found.
A genuine unforeseen condition does not remove the need for approval. It explains why a change may be required.
2. An initial quotation with too little detail
Broad descriptions create room for different interpretations. A line such as “renovate bathroom” does not define demolition, disposal, preparation, waterproofing, sanitaryware, fittings, tiling quantities, painting or service alterations.
The owner may reasonably believe an activity is included. The contractor may have priced a narrower interpretation. If that difference is discovered halfway through the work, the owner must decide under time pressure.
3. Poorly defined scope
The scope should state what will be done, where it will be done and to what standard. It should also identify quantities, responsibilities, materials, exclusions, assumptions and acceptance criteria where these are relevant.
If those points are absent, some items described as extra work may be work that was never defined properly at the start. The owner needs to compare the new request with the original documents before accepting the classification.
4. Changes requested by the owner
Owners change their minds. A different layout, finish, lighting design, item of equipment or material may be appropriate as the property develops.
The change should still be treated as a project decision. A small visible alteration can affect procurement, lead times, specialist design, several trades and completed work. Its full cost is not always limited to the price difference between two products.
5. Defective work or rework
Work that does not meet the agreed requirement may need correction. That correction should not automatically be presented as a new owner cost.
The original instruction, approved material, inspection record and evidence of the completed work help establish what happened. The owner should obtain technical and contractual advice appropriate to the situation before agreeing responsibility.
6. Poor coordination between disciplines
Incompatibilities between the architectural, engineering and technical specialist designs can also create avoidable extra work when they are not identified and communicated in time. A detail may need to change because two parts of the design do not coordinate or because information arrives after the relevant trade has priced the work.
The owner does not need to resolve that technical comparison alone. Independent supervision acts as the central communication channel between the relevant designers, specialists and contractor, helping clarify the requirement, record what changed and resolve dependencies before they become rework, added cost or delay.
Why does extra work create so much conflict?
Change requests often arrive when the building is open, the contractor is mobilised and the next trade is waiting. The owner has already committed money and may fear that asking questions will stop the project.
The contractor may also face a real issue. The discovered condition may be outside the priced scope, labour may be waiting and a decision may be needed before the area can be closed.
Conflict grows when either party feels surprised. An owner may ask:
- Was this not included?
- Why has it only been raised now?
- What evidence shows the work is needed?
- How was the price calculated?
- What happens to the programme if I do not approve it today?
- Are there other options?
The contractor may say:
- This activity was not in the quotation.
- The condition could not be seen earlier.
- The owner requested a change.
- The next activity cannot proceed until there is a decision.
A documented change process turns these positions into a defined question. It gives all parties the same description, evidence, price, programme effect and decision record.
By standing between the owner and contractor, independent supervision takes on the strain of these difficult conversations on the owner’s behalf. Technical, impartial mediation helps preserve the professional relationship between the parties and reduces the risk of cost and programme decisions being made under emotional pressure at the project’s most vulnerable moment.
What should be in writing before extra work is approved?
A request does not need to become a long bureaucratic document. It does need enough detail for the owner to make an informed decision.
1. A precise description
The description should identify the area, quantity and activities included. “Resolve plumbing problem” is too broad. “Replace eight metres of existing pipework in the main bathroom, including opening, removal, new installation, testing and closing the channels” gives a basis for review.
The scope should also state what is excluded. If making good, decoration, disposal or testing is not included, that omission may create another request later.
2. The reason for the work
The owner should know whether the request comes from an unforeseen condition, owner change, design revision, original omission, product substitution or correction. The reason affects both the technical decision and the discussion about responsibility.
3. Evidence of the condition
Photographs, measurements, marked drawings or a short technical note may be appropriate. Evidence should identify the date and location. If the work will soon be concealed, the current condition should be recorded before it disappears.
4. Additional cost
The proposed cost should be agreed before execution. The level of detail should match the size and complexity of the change. Materials, labour, specialist subcontractors, plant and related work may need to be separated so the owner can see what the total covers.
The review should also compare the proposed rates and quantities with relevant items in the original budget where possible.
5. Programme and sequencing effect
Extra work can affect more than its own duration. It may delay the next trade, change a delivery date or require completed work to be reopened. The request should state the expected effect and any dependency on a rapid decision.
6. Alternatives
There may be several technically acceptable responses, each with different cost, durability, appearance or programme implications. The owner should receive those trade-offs rather than a single unexplained instruction when alternatives exist.
7. Consequences of not proceeding
Some changes are optional. Others may be required to complete the intended work or avoid damage to later stages. The owner should understand what can proceed, what must pause and what risk remains if the proposal is rejected or deferred.
8. Written owner approval
The final decision should be dated and recorded. Email, a change form, meeting minutes or another agreed record may be used. The important point is that the description, price and programme effect approved by the owner can be traced later.
A practical extra work approval record
A simple record can include:
- Change reference number.
- Date of proposal.
- Area and trade.
- Description of the additional work.
- Reason for the change.
- Supporting photographs, measurements or drawings.
- Additional cost and what it includes.
- Effect on the programme and sequencing.
- Alternatives considered.
- Technical recommendation.
- Owner decision.
- Date and method of approval.
The purpose is not paperwork for its own sake. At the end of the project, the owner should be able to see why each additional amount entered the budget and what was delivered for it.
As part of CMSI’s service, this approval record and the final checklist are provided to the client as ready-to-use tools adapted to the project. The service includes not only site supervision, but also the practical instruments needed to record, assess and approve each change consistently.
How does independent site supervision control extra work?
Independent supervision supports the owner before, during and after the decision.
Before the decision
The supervisor reviews the existing scope, relevant design information, site condition and contractor’s explanation. This helps identify whether the work is genuinely new, a development of the original requirement or potentially connected with work already included.
The supervisor can request missing details and make the comparison understandable for the owner. A recommendation should state its basis and any evidence that is not yet available.
During the decision
The owner receives a clear summary of what changed, why it changed, what it costs, how it affects the programme and what options exist. Where input is needed from the architect, engineer or specialist designer, that decision should be coordinated rather than guessed on site.
Independent supervision also brings knowledge of current market prices. CMSI can identify inflated rates or quantities in extra work proposals and negotiate on the owner’s behalf so that the proposed value reflects the actual scope and site conditions.
After the decision
The approved change is added to the project records and budget. Its execution is followed like any other work. Photographs, measurements and open items should show whether the agreed scope was completed before payment is recommended.
Supervision cannot remove every change. It prevents a change from entering the project as an unexplained surprise.
How can owners reduce extra work before construction starts?
Some uncertainty is unavoidable, especially in an older building. Good preparation can still reduce omissions, incompatible assumptions and late decisions.
Review proposals before appointment
Comparing only the final total is risky. One contractor may include disposal, preparation and specialist work that another has excluded. A higher total may cover a more complete scope, while a lower total may rely on allowances or assumptions.
A comparison schedule should place similar items side by side and identify missing information. Owners should not have to perform this technical comparison alone.
Confirm inclusions and exclusions
The proposal should make the limits clear. Disposal, permits, transport, access equipment, surface preparation, final cleaning, testing, specialist works and certification may all create later cost if responsibility is not defined.
The list should be project-specific. A generic statement that “everything necessary” is included is difficult to verify.
Specify materials and performance
“Quality material” is not a specification. The project may need a product reference, finish, size, performance requirement or approved equivalent. If an allowance is used, its basis and the process for selecting the final item should be clear.
Investigate existing conditions where proportionate
Surveys and opening-up inspections may reduce uncertainty before the final scope is priced. They cannot reveal every condition. Their purpose is to improve the available evidence, not to guarantee that the existing building contains no surprises.
Define the change process
The owner and contractor should know who can propose a change, who provides technical input, who confirms price and programme effect, who approves it and how the record is distributed. A response period may also be useful for decisions that affect the sequence.
Maintain a contingency
A contingency is a planned allowance for uncertainty. It is not permission to spend without approval. Every proposed use should still follow the same review and written decision process.
How should extra work be compared with the original budget?
The new proposal should be read alongside the accepted scope, exclusions, drawings, specifications and previous change records.
Useful questions include:
- Was the activity expressly excluded?
- Was it described in broad terms that could include this work?
- Was the condition reasonably visible before the price was agreed?
- Is the change caused by a new owner decision?
- Has the design or specification changed?
- Is it connected with correction of completed work?
- Do the quantities and rates correspond with similar original items?
- Does the proposed duration reflect the work and its effect on other trades?
- Are making good, testing and associated work included?
The answer may require input from more than one party. The purpose of the questions is to prevent automatic approval, not to assume the contractor’s request is invalid.
How should extra work be handled in stage payments?
An approved change becomes part of the controlled project budget. Approval to proceed is not the same as confirmation that the work is complete and payable.
Before recommending payment, check:
- Was the change approved in writing before execution?
- Does the completed work match the approved description?
- Are measurements or dated site records available?
- Have concealed stages been recorded before covering?
- Are there incomplete items or unresolved non-conformities?
- Does the invoiced amount match the approved value and measured progress?
- Has the programme effect been added to the current record?
This process does not mean that every minor observation must stop every payment. It means the recommendation should state clearly what has been completed, what remains open and how those items affect the amount under review.
Common owner mistakes
Approving by telephone only
A call may be necessary to discuss an urgent point. The decision should still be confirmed in writing with the agreed scope, price and programme effect. Otherwise, each party may remember the conversation differently.
Accepting a price without scope
A total amount does not explain what will be delivered. The owner needs a description detailed enough to inspect and measure the result.
Treating urgency as the absence of options
A technical issue may need a quick response, but the owner still needs minimum clarity: what was found, what is proposed, the cost, the effect of delay and who recommends the solution.
Paying immediately after approval
Approval allows the work to proceed. Payment should reflect the agreed payment terms and verified progress. If the change includes several stages, the record may need to distinguish work started from work completed.
Failing to update the overall budget and programme
Several individually approved changes can materially alter the project. The owner should see the cumulative approved value, pending requests, remaining contingency and current completion forecast.
Keeping decisions in separate message threads
Important instructions can become difficult to trace across messaging applications, calls and emails. The central change register and weekly report should point to the approved record.
Checklist for approving extra work
Before approving, confirm:
- Is the work described by location, quantity and activity?
- Is the reason clear?
- Is the existing condition supported by evidence where relevant?
- Does the proposal identify related making good, testing and exclusions?
- Is the additional cost defined?
- Is the effect on the programme and other trades stated?
- Have reasonable alternatives been explained?
- Is the consequence of rejecting or delaying the work clear?
- Has the appropriate designer or specialist provided input if needed?
- Is responsibility for the decision recorded?
- Will the owner approval be dated and kept with the project records?
- Will completed work be validated before payment is recommended?
If several points are unanswered, the owner does not yet have a complete basis for the decision.
Conclusion: the problem is not change, but uncontrolled change
Extra work is common in construction and particularly in renovation. The aim is not to pretend that every unknown can be removed before work starts. It is to stop a change from becoming an unpriced instruction, an unexplained delay or a surprise invoice.
When each proposal is described, evidenced, priced, programmed and approved in writing, the owner can make a better decision. The contractor receives a clearer instruction. The project record shows what changed and why.
CMSI helps owners establish this process through proposal comparison, independent site follow-up, structured change records, progress reporting and validation before payment recommendation. If you are preparing a project or have started receiving requests for extra work, CMSI can review the available evidence and identify the decisions that should be clarified before work proceeds.
FAQ
Is extra work always a sign that something has gone wrong?
No. Existing buildings can contain concealed conditions, and owners may request legitimate changes. The important point is that each request is explained, priced, assessed for programme impact and approved in writing before execution.
Can an owner refuse extra work?
It depends on the proposal and its consequences. Some changes are optional. Others may be necessary to complete the intended work or address a technical condition. The owner should understand the evidence, alternatives and effect of refusing or delaying before deciding.
Should a contractor carry out extra work without approval?
The project process should avoid that situation. Any proposal that changes cost, programme or scope should be presented and approved before execution. If an urgent condition requires immediate protective action, the scope of that action and the route for further approval should be recorded as soon as possible.
How can I assess whether the price is reasonable?
Check quantities, labour, materials, associated work and exclusions. Compare rates with relevant original budget items where possible. Price should be reviewed together with scope, urgency, programme impact and available alternatives. An independent technical review may help when the comparison is complex.
Does site supervision eliminate extra work?
No. It can identify omissions before commitment, document unforeseen conditions, review requests and follow approved changes. It does not promise that an existing building will contain no unknown conditions.
When should I seek independent support?
Ideally before contractor proposals are accepted, so scope and exclusions can be compared. Independent support can also be introduced when additional costs, delayed decisions, quality questions or unclear payment requests arise during the work.