The covering comes off and soft boards appear beside the valley. A roofer variation process stops that discovery becoming unpaid work, a rushed site decision or a surprise on the final invoice.
Treat deck exposure as a hold point. Make the area safe. Map and measure the damage. Compare it with the quotation. Price any added work and get written approval before the crew installs it.
Put concealed deck risk into the quotation
A roof survey can show visible defects. It cannot confirm every board or sheet hidden below the existing roof build-up.
The quotation sets the boundary for the roofer variation process. Write that boundary before strip-off, while the roof is still covered and everyone can make a calm decision.
State the deck condition assumed by the price
Name the deck type you expect where it can be identified. State the condition assumed by the price. For example, the quotation might assume that the existing decking can receive the specified roof system and fixings.
If the deck type cannot be confirmed, say it will be checked after strip-off. Do not write vague lines such as repair as required or concealed damage extra. Those words give the crew no stopping point and the customer no basis for checking the bill.
Record defects already visible during the survey. If a known damaged area is included, locate it by roof plane and fixed points such as a valley, chimney, wall or opening.
Define included repairs and the variation trigger
State whether the price includes any deck replacement. If it does, give the quantity, location and measurement method. Explain what happens when the included quantity has been used.
The quotation should record:
- the deck condition assumed by the price
- any included repair quantity and location
- the unit used to measure additional work
- how partial boards, sheets or irregular areas will be counted
- work excluded from the roof scope
- the condition that triggers a variation
- the point where the crew must stop and report
Keep suspected structural work separate from routine deck replacement. Do not bury framing, masonry, flashing or design work inside a general deck allowance.
Use the quote template to set out the original scope, exclusions and concealed-deck assumption in one document.
Choose the pricing method before the deck is visible
Decide how changed deck work will be priced before strip-off. You can include a defined repair quantity, use a stated measurement method or prepare a fixed variation after exposure and measurement.
Whichever method you choose, define the unit and rounding rule. State whether the measurement covers removal, cutting, fitting, fastening, handling and disposal. Do not change the method after exposure because another method produces a better selling price.
If further damage may remain concealed beyond the first opened area, state that the approval covers only the measured work. Give the crew another hold point at the new boundary.
Set the approval chain before opening the roof
Find out who can approve roof scope changes. Identify the contracting customer and each named representative with delegated authority, including any approval limit.
Record one primary authorised contact and a backup. Write down where approval must be sent and whether the customer requires a particular reference on the variation. Do this before materials arrive.
Do not assume that a spoken instruction from somebody at the property changes the contract. The person must have authority to accept the scope, price and programme effect.
Separate temporary protection from permanent work
Temporary weather protection and permanent deck replacement are different instructions.
Agree what the crew may do if the authorised contacts cannot be reached. The instruction should describe the temporary protection allowed and the record the crew must make. It should not give open authority to replace whatever damaged deck appears.
If the roof cannot safely remain exposed, protect it under the agreed instruction and pause permanent unquoted work. Follow the roofer wet-weather plan for securing the site, recording the delay and restarting the job.
Use a deck-exposure hold point in the roofer variation process
The covering and underlay have been stripped. Soft boards appear beside a valley that looked sound during the survey. Stop there.
Control access to the affected roof plane. Keep the crew away from material that may not support them. Make the area safe under the job method before anyone measures, cuts or removes more material.
One person should record the discovery. That avoids several crew members sending different descriptions and quantities to the office.
Locate the damage before measuring it
Start with the roof plane. Then use fixed reference points: ridge, eaves, valley, chimney, wall, rooflight or other opening.
Mark the current edge of the visible damage. A total quantity without a location is not a usable instruction. The customer cannot see what is changing, and the crew cannot tell where the approved work ends.
Take a wide photograph that shows the roof location. Take close photographs that show the visible condition. Add a tape, rule or marked drawing where it helps explain the measurement.
Photographs support the variation. They do not replace a defined scope, price and written acceptance.
Measure with the method in the quotation
Use the unit stated in the original quotation. Record boards, sheets, area or another defined unit consistently.
For partial sheets or irregular areas, follow the stated counting rule. For boards, record their position and replacement length. If controlled removal reveals more damage, measure the new section separately and stop again at the agreed boundary.
The quoted deck repair allowance may already have been used when more damaged decking appears towards a chimney. Record the included quantity used before raising an added quantity. Otherwise the customer may be charged twice for the same work.
Classify the discovery before pricing it
Compare the exposed condition with the quotation. Use the written scope, assumption, allowance and exclusions. Do not rely on what somebody remembers from the survey.
Put the discovery into one of three buckets:
- included work within the quoted quantity
- additional deck work that needs a variation
- work outside routine deck replacement that needs another qualified party
If the work is included, record it against the quoted quantity and release only that work. If it crosses the written boundary, define the added scope before pricing it.
A roofer may remove one damaged board and expose a condition near the supporting structure. Do not label that routine deck replacement. Record what is visible, make the area safe and pass the question to an appropriately qualified party where needed.
Keep roof scope changes narrow. Decking, supporting structure, flashing, masonry and work around openings are not one vague extra. Separate them so each instruction has a clear owner and boundary.
Apply a short UK compliance gate
Identify the issue. Check the right authority. Record the answer. Then release the defined work.
Do not send every routine deck replacement to building control. Contact building control (opens in a new tab) in England when the added scope may change approved work or you cannot tell whether building regulations approval is affected. In Wales, use the Welsh Government building regulations guidance (opens in a new tab). In Scotland, ask the local building standards service and use the Scottish Government building standards guidance (opens in a new tab). In Northern Ireland, ask the local council building control service and check the nidirect building regulations guidance (opens in a new tab).
If the discovery creates doubt about the supporting structure, stop the affected work and refer it to a competent designer or other appropriately qualified party. Building control does not replace the person responsible for assessing and specifying that work.
For workplace health and safety questions in England, Scotland or Wales about exposing, inspecting or replacing the deck, check with the Health and Safety Executive (opens in a new tab). For a job in Northern Ireland, check with the Health and Safety Executive for Northern Ireland (opens in a new tab). Record the site instruction before the crew returns to the affected area.
Check the current VAT treatment for the variation in the HMRC VAT guidance (opens in a new tab). Separately, use the HMRC CIS guidance (opens in a new tab) to check the scheme’s scope and what the business must do about verification, deductions and payment records. Give the office a separate instruction for each.
Price the measured change without charging twice
Build the variation from the work that changed. Start with the measured location and proposed quantity, then compare it with the quantity or allowance included in the quotation.
Define the net added scope first. Credit the included quantity or allowance using the pricing basis stated in the quotation. The remaining measured work is the scope you need to cost.
Cost labour by task for that net added scope. Include removal, handling, cutting, fitting, fastening and reinstatement where those tasks are part of the changed work. Use your own labour cost rather than a guessed roofing rate.
Add the deck materials, fixings and consumables needed for the net added scope. Add job-specific access, equipment, disposal and subcontractor costs only where the change causes them.
Those entries form the new cost base. Add your chosen markup to produce the variation price. Markup is what you add to cost to make the selling price. Margin is profit as a share of that selling price.
Worked example: follow the document chain
The house example is electrical, but the document control works the same way. R. Chen at 14 Oak Street accepted quote Q-1847 for a bathroom exhaust fan and four LED downlights. The quote total was 1,105 sample currency units.
The ceiling was lined and the quote excluded chasing. Extra cable and chasing were approved on site as a 160 variation. Invoice INV-1847 was therefore 1,265.
The given job cost of 850 is measured against the original quote only. Profit is 1,105 − 850 = 255. Margin is 255 ÷ 1,105, about 23%. Markup is 255 ÷ 850 = 30%.
The variation costs are not supplied. Do not combine the 850 cost with the 1,265 invoice or calculate profit on the variation. Use the profit margin calculator with costs taken from your own roofing job.
Write one variation the customer can decide
Send one complete decision. Do not scatter the photographs, quantity, price and timing effect across unrelated messages.
Use a variation number and link it to the customer, property, job and original quotation. State what the crew found without diagnosing work outside its competence.
Copy this blank record into your job file:
Variation number: [reference] Customer: [name] Property: [address] Job reference: [job number] Original quotation: [number and date] Discovery date: [date] Recorded by: [name] Discovered condition: [Describe the visible deck condition.] Location: [Roof plane and fixed reference points.] Evidence: [Photograph numbers and marked drawing references.] Original inclusion or allowance: [Quoted line, quantity, pricing basis and measurement method.] Included quantity already used: [Quantity and location.] Added measured quantity: [Unit, quantity and treatment of partial areas.] Net added scope: [Added measured work less the included quantity or allowance, credited using the quotation’s stated pricing basis.] Added work: [Removal, cutting, fitting, fastening, handling, disposal and reinstatement.] Price build-up for the net added scope: Labour: [task costs] Materials and consumables: [cost] Job-specific access or equipment: [cost] Disposal: [cost] Subcontractor work: [cost] New cost base: [cost] Markup: [business markup] Variation price: [selling price] VAT presentation: [use the checked VAT treatment for this variation] Still excluded: [Work not included in this approval.] Programme effect: [Change to sequence or completion.] Temporary protection: [Instruction and record required.] Customer approval: [Authorised name, acceptance, date and approved amount.] Crew release: [Approved location, quantity and next hold point.]
Use the VAT treatment checked for the variation. Record any separate CIS instruction in the office job record rather than treating it as part of the customer’s VAT presentation.
Get extra roof work approval and release a firm boundary
Send the authorised customer the variation, photographs, measured quantity, price and programme effect together. Ask for written acceptance at the agreed destination.
If approval is missing, hold the permanent extra work. Use only the temporary-protection authority already agreed. Record the protection installed, who was contacted and when the request was sent.
Once extra roof work approval arrives, the office or named site supervisor issues the crew release. It must state the variation reference, roof plane, fixed reference points, approved quantity and next stopping point. The crew leader records the actual quantity completed against that variation before the work is covered.
If the approved quantity is used and more damage appears, stop again. Raise another variation or extend the existing one through a fresh written acceptance. Approval for one measured area does not open the whole roof.
Close the change through the invoice and job record
Keep the original quotation, site photographs, measured record, approved variation, crew release and invoice attached to the same job. The document chain should show what was priced, what changed, who accepted it and what was completed.
Add the approved variation to the correct billing stage. The roofer stage payment invoice guide explains how to keep completed work, variations and the final balance clear without rewriting the original quotation.
Put actual variation labour, materials, consumables, access and disposal into cost tracking as part of the roofer variation process. Do not leave the changed work in a general roof-cost bucket. Compare the approved variation price with the costs caused by that variation.