How to invoice variation orders and extras UK (2026)
How to invoice variation orders and extras UK (2026)
By InvoiceAdept Team29 March 2026Updated 29 August 202613 min read
This page is the process for extras and variation orders. It is not a second invoice template. When you need the field list for a trade PDF — labour, materials, CIS columns — open the relevant template: electrician, plumber, roofer, builder, carpenter. Stay here for when to confirm an extra, how to code it, and how CIS and VAT treat it.
An older version of this page invented dispute and cost-overrun statistics and treated a signed variation order as the only legal path to payment. That was wrong for Saturday extras on a householder job. Domestic trades confirm extras in WhatsApp or email every week. Main-contractor and JCT work wants a numbered VO against the purchase order. Be honest about both.
Rules from GOV.UK. Worked figures below are illustrative only, not a price list. General information for UK trades, not tax or legal advice.
InvoiceAdept is from Tech Me Today Ltd, Companies House 15917255, ICO ZB944663. Free: five invoices a month. Pro £7.99. Pro+ £12.99 (CIS). No InvoiceAdept platform fee on Stripe. We do not file CIS300, VAT returns or Making Tax Digital updates to HMRC.
In short
Confirm the extra in writing before you do it. Code it V01 (then V02). Put it on own lines, never as a buried lump inside the original package. Split labour and materials if CIS applies. Invoice the extra when the work is done, or on the next stage invoice — do not invent a second live number for the original job, and do not silently inflate the original lump.
WhatsApp or email counts as writing for a homeowner. A signed PDF is best on main-contractor work; it is not a requirement to get paid for a Saturday extra if the chat shows they asked for it and you priced it. Retention is not a variation. A deposit is not a variation. VAT registration is £90,000. InvoiceAdept keeps digital records; it does not file to HMRC.
General walkthrough: how to invoice a UK client as a tradesperson. Deposit process: deposit invoice template UK. WhatsApp send: WhatsApp invoicing UK.
Who is paying for the extra
A homeowner asking for another bedroom wallpapered, a landlord’s agent adding sockets, and a main contractor issuing VO-03 against a purchase order are three different paper trails. Get the customer type wrong and you chase the wrong inbox with the wrong document.
Homeowner / private client | Landlord / managing agent | Main contractor / JCT or PO job | |
|---|---|---|---|
How extras usually start | Chat, site visit, “while you’re here” | Email or portal ticket from the agent | Instruction against the PO / valuation |
Confirm in writing | WhatsApp or email with price and scope is enough for most domestic extras | Email to the person who hired you; copy the landlord if they pay | Numbered variation order (V01…) against the contract / PO; signed PDF preferred |
What the invoice needs | Description of the extra, labour and materials, link to the chat date | Property address, agent ref, who pays | PO, site/plot ref, VO number, labour/materials split, UTR if CIS |
How they pay | Card, Apple Pay, same-day transfer | BACS from the agent or landlord | BACS on their run, often 14–30 days |
What you do not do | Demand a JCT-style signed VO before a £300 Saturday extra, then refuse the chat trail | Bill the tenants when the agent hired you | Email a domestic-looking PDF with 20% VAT tacked on when reverse charge applies |
A signed PDF is the cleanest record on contractor work. It is not the only path to a payable domestic extra. If the homeowner wrote “yes, do the second bedroom, £220 labour + £85 paper” and you did that work, you have a written confirmation. Keep the thread. Photograph the extra. For more on chat as a record: WhatsApp invoicing UK.
What counts as a variation (and what does not)
A variation is a change to the agreed scope, materials or specification on this job. It is not every awkward conversation on site.
Situation | Treat as | Why |
|---|---|---|
Extra room, extra elevation, extra sockets, colour change mid-job | Variation / extra | Scope grew after the quote |
Rotten timber, failed membrane, asbestos surprise found once opened up | Variation if they approve the fix | Unforeseen but still a change to what was priced |
Client changes the spec (different tiles, different sanitaryware) | Variation | Their instruction; price the difference |
Snagging — paint touch-up, screw heads, a hinge that sticks | Defects under the original scope | Not an extra charge unless the quote said otherwise |
A second property, or a wholly new package months later | New job | New quote, new invoice number sequence for that job |
Retention release after completion | Retention invoice | Not a variation — money already earned, held back |
Deposit / advance before materials | Deposit invoice | Not a variation — see deposit template |
If you are unsure, ask: did the original quote already cover this? If yes, it is snagging or a programme issue. If no, price it as an extra and get a yes before you start.
Many UK tradespeople also find it helpful to review VAT invoice requirements UK 2026 at this stage.
Confirm in writing before you start
Do not start the extra and hope. Confirm, price, get a yes, then do the work.
Describe the extra in one or two sentences: what, where, why it was not in the original quote.
Price labour and materials separately — especially if a contractor will pay you under CIS.
Send it in writing — WhatsApp, email, or a short PDF variation note. Photo of the rotten timber or the blank wall helps.
Wait for a clear yes — “OK do it”, “agreed £X”, a tick emoji after your price, a signed VO. Silence is not agreement.
Keep the thread with the job folder. You will need the date on the invoice line.
Signed PDF is best when a main contractor, QS or accounts team will process the bill. For a householder on a Saturday, a WhatsApp yes with the price is written confirmation. Do not tell domestic clients they have no liability unless a wet-ink signature exists — that overstates the position and matches the bad advice this page used to give.
If they refuse to confirm: do not do the extra. Do not start and hope. If you already did it without a yes, you are arguing, not invoicing. Negotiate, or walk away from that slice of work. Do not invent a line later and surprise them on the final account.
How to invoice the extra
Two clean methods. Pick one per job and stick to it.
1. Own lines on the next stage (or final) invoice
Add coded lines to the next invoice you were going to raise anyway:
V01 — Extra bedroom wallpaper, labour, as WhatsApp 12 Aug 2026 — £220V01 — Extra bedroom wallpaper, materials — £85
Same invoice number you would have used for that stage. Own lines. Own codes. Never bump the original “full redecorate package” lump from £2,400 to £2,705 in silence.
2. Separate variation invoice the same day
Raise a new invoice only for the extras, same day the work finishes (or the day they approved, if you bill approval-first on contractor work). Reference the original job / quote / PO. Still code V01, V02. Useful when accounts want extras on their own PDF, or when the stage invoice is already with the QS.
What never to do
Never create a second live invoice number for the same original scope (that looks like double-billing). Credit-and-reissue if you must correct the first bill.
Never inflate the original lump without a VO code the client can see.
Never bury “sundries £800” that are really six sockets and a coil of cable.
Never reuse an invoice number you already sent.
Legal baseline for what an invoice must include: GOV.UK — invoices, what they must include. Field lists by trade live on the templates linked above, not here.
InvoiceAdept Free is five invoices a month. Deposit + stage + final + a separate variation invoice will burn the cap. That is the product doing what it says. Pro removes it. See pricing.
CIS on extras
CIS applies because a contractor is paying you for construction operations, not because the line says “extra”. A homeowner paying for wallpaper: no CIS. A main contractor paying for six extra sockets on plots 8–11: CIS on the labour.
Extra labour is still CIS labour. Extra materials you bought for this extra are materials if evidenced (merchant ticket matching this address / this VO). One lump “extras £800” is how a cautious contractor deducts 20% of the lot — including the cable and the sockets.
Line on the variation | CIS treatment (when a contractor pays you) |
|---|---|
Extra labour for the VO | In — deduct at 20% verified / 30% unverified |
Materials you bought for this extra, evidenced | Out of the labour base if the contractor accepts the evidence |
Free-issue from their stores | Not your materials — do not list as yours |
Mark-up on materials | Labour, not materials |
You invoice gross. They withhold from labour. Show the split so they can. Rates and scheme basics: GOV.UK Construction Industry Scheme. CIS lines sit on InvoiceAdept Pro+ (£12.99). The printout is not a CIS300. The contractor files the monthly return. InvoiceAdept does not.
VAT, reverse charge, and the tax point on extras
Extras are a new supply (or an addition to the supply) for VAT. If you are VAT-registered, charge the right rate — usually 20% standard-rated on work to an existing occupied dwelling. Check VAT Notice 708 for zero-rated new dwellings and reduced-rate cases; do not guess from a forum.
If domestic reverse charge applied to the original contractor job, it usually applies to the extra too — same parties, same kind of construction services, same CIS reporting. Show the VAT; do not add it to what they pay. Never put reverse charge on a private homeowner extra. Walkthrough: domestic reverse charge invoice UK.
A deposit on extras: if you are VAT-registered and you receive money for the extra before (or as) you do it, receipt is usually a tax point for that amount on the day it lands. Do not wait until the final account to “put all the VAT on the last bill”.
The VAT registration threshold is £90,000 of taxable turnover in a rolling 12 months — register for VAT if you have gone over, or will. Older pages (including some of ours) still said £85,000. That figure is stale. Do not copy it. Track turnover from the invoices you actually raise, including extras and deposits.
If you are sorting this alongside other compliance work, read Conservatory invoice template UK.
Worked examples (illustrative only)
These figures are examples to show the process, not a price list or a claim about typical UK rates.
Homeowner painter — extra bedroom wallpaper
Original quote: full ground-floor redecorate. Mid-job, client asks for the spare bedroom wallpapered.
Confirm in WhatsApp, 12 August 2026: labour £220, materials £85.
They reply “yes please”.
On the final invoice, add:
- V01 — Spare bedroom wallpaper, labour, WhatsApp 12 Aug 2026 — £220 - V01 — Spare bedroom wallpaper, materials — £85
No CIS. No reverse charge. If VAT-registered, add VAT at the correct rate on those lines.
Do not bump the original package line and hope they do not notice.
Contractor electrician — extra six sockets, plots 8–11
Working under a main contractor, CIS verified, reverse charge on the package.
Extra: six double sockets across plots 8–11. Labour £360, materials £94 (ticket kept).
Raise VO / get written instruction against the PO. Code V01.
Invoice (separate variation or next valuation — whatever their QS asked for):
- labour £360 (CIS applies — they deduct 20% from labour) - materials £94 (evidenced — out of labour base if accepted) - reverse charge wording on the extra, same as the original supply
Do not send a domestic PDF with 20% VAT added to the total they pay.
Field layout for electrics: electrician invoice template UK.
Roofer — second elevation, rotten timber and extra lead
Strip and re-tile agreed for the front elevation. Opening up shows the side elevation needs lead and timber.
Photo the rot. Price labour, timber, lead separately.
Get written approval (email or WhatsApp from the person who hired you; numbered VO if a contractor).
Invoice as V01 own lines on the next stage or a same-day variation invoice — not a silent bump inside “re-tile front elevation”.
Process detail for roofing cashflow: invoicing for roofers. Fields: roofer invoice template.
Late extras near completion
Clients often invent a wish-list in the last week. Treat late extras the same as early ones: confirm in writing, price, get a yes, then start — or say no.
Late extras can push practical completion and retention release. Say so in the confirmation: “Extra sockets V02 — labour £180 materials £40 — adds two days; final account moves from Friday to Tuesday.” If they need the keys on Friday, they choose: skip the extra, or accept the new date.
Do not absorb a late extra into “goodwill” and then resent the unpaid hours. Either it is a coded, agreed line, or it is not on the invoice.
Commercial payment timing for business-to-business work: GOV.UK late commercial payments. That regime does not turn a domestic chat into a statutory interest claim by itself — know who you contracted with.
Retention and deposits are not variations
Retention is money held back from sums already earned, released after a defects period. Invoice the release when due. Do not call the release a variation.
Deposit / advance is money taken before (or early in) the job so you can order materials or book access. Invoice it when received. Sister page: deposit invoice template UK.
Mixing the three words on one PDF is how homeowners and accounts both bounce the bill. Extra = change to scope. Deposit = advance. Retention = hold-back.
Making Tax Digital: records, not filing
If your qualifying income is over £50,000 for 2024–25, Making Tax Digital for Income Tax applies from 6 April 2026, with lower thresholds later. GOV.UK — when you need MTD.
What you need from invoicing software for extras:
a dated digital record of every variation invoice and payment
labour and materials visible so CIS and VAT can be checked later
the written confirmation (chat export or PDF) stored with the job
What InvoiceAdept does not do — and what no honest “stay MTD-compliant” button should claim:
send quarterly Income Tax updates to HMRC
submit Self Assessment
file your VAT return
file the contractor’s CIS300
Records are not filing. Pair invoices with software that does file, or with your accountant. Detail: InvoiceAdept and MTD for UK trades.
Related: see How to invoice for the first time UK for practical next steps.
How InvoiceAdept fits
Domestic extras confirmed in WhatsApp: put the invoice in that thread. Native send is Pro; Free users attach the PDF. Contractor VOs: email accounts with the PO and VO number.
InvoiceAdept Free | InvoiceAdept Pro | InvoiceAdept Pro+ | |
|---|---|---|---|
Price (checked 29 Aug 2026) | £0 | £7.99 / month | £12.99 / month |
Invoices | 5 per month | Unlimited | Unlimited |
CIS lines | No | No | Yes |
WhatsApp send | Share a PDF yourself | Yes | Yes |
Files CIS300, VAT returns or MTD to HMRC | No | No | No |
Extras burn the Free cap fast: original stages plus a separate variation invoice are still invoices. Pro removes the cap. No InvoiceAdept platform fee on Stripe. Pricing · invoice generator.
Mistakes that turn extras into arguments
Starting the extra without a written yes, then “invoicing” it on the final account.
One lump “extras £800” on a CIS job so 20% comes off materials too.
Silently inflating the original package line instead of coding V01.
Demanding a signed JCT-style VO for every domestic Saturday change, while ignoring the WhatsApp trail you already have.
Putting CIS or reverse charge on a homeowner extra.
Using the old £85,000 VAT threshold. It is £90,000.
Treating retention release or a deposit as a “variation”.
Inventing a second live invoice number for the same original scope.
Assuming the invoicing app files MTD, VAT or CIS300. InvoiceAdept does not.
Quoting unsourced “20% of disputes” or “variations add 15% to costs” as if they were facts. An older version of this page did that. Those claims are removed.
Worth pairing this with our guide to How to invoice subcontractors UK CIS.
Frequently asked questions
Do I need a signed variation order before every extra?
No. On main-contractor / JCT / PO work, a numbered signed VO is the professional path and what accounts expect. On domestic work, WhatsApp or email with a clear price and a clear yes is written confirmation. A signed PDF is best when you can get it; it is not the only way a householder extra becomes payable.
Is WhatsApp enough to confirm an extra?
Yes for most homeowner jobs — if the message shows what was agreed and the price. Keep the thread. Photograph the work. For contractor jobs, follow their VO process as well. More: WhatsApp invoicing UK.
Should extras go on the next stage invoice or a separate invoice?
Either. Own coded lines (V01…) on the next stage or final is fine. A same-day separate variation invoice is fine when accounts want extras alone. Never a second live number for the original lump, and never a silent bump inside it.
How does CIS treat variation labour and materials?
Extra labour is still CIS labour when a contractor pays you. Evidenced materials for that extra can sit outside the labour base. A single “extras” lump invites 20% on the lot. GOV.UK CIS.
What if reverse charge applied to the original job?
It usually applies to the extra between the same VAT-registered CIS parties. Show VAT; do not add it to the amount due. Never on a private client. Domestic reverse charge guide.
What is the VAT threshold in 2026?
£90,000 of taxable turnover in a rolling 12 months, not £85,000. Register for VAT. Extras and deposits you invoice count toward that figure.
What if the client refuses to confirm the extra?
Do not do the work. Do not start and hope. If you already did it without agreement, you are in a dispute, not a clean invoicing workflow — negotiate or get advice; do not surprise them with a line on the final.
Are snagging, retention and deposits variations?
No. Snagging is usually defects under the original scope. Retention is hold-back on money already earned. A deposit is an advance — see the deposit invoice template.
Does InvoiceAdept keep me “MTD-compliant”?
No. It stores digital invoice records you can export. It does not send quarterly MTD updates, VAT returns, Self Assessment or CIS300 to HMRC. Use the MTD for UK trades guide for the records-versus-filing split.
Where are the trade invoice templates?
Electrician, plumber, roofer, builder, carpenter. This page is the extras process; those pages are the field lists.
About this guide
InvoiceAdept is invoicing software for UK trades (Tech Me Today Ltd, Companies House 15917255, ICO ZB944663). CIS on Pro+. We do not file CIS300, VAT returns or MTD updates.
Invoice generator · Pricing · How to invoice a UK tradesperson client.
Further reading on contracts (not affiliated): Federation of Master Builders and JCT publish contract guidance on their own sites — use those for form wording; this page is about invoicing the extra once it is agreed.
Last reviewed: 29 August 2026. Check the GOV.UK pages linked above before you rely on a rate or threshold. General information for UK tradespeople, not tax or legal advice. An earlier draft of this URL cited unsourced dispute and cost-overrun percentages; those claims have been removed.
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