Extra works authorisation, signed on a phone
An extra works authorisation is the homeowner’s written, priced yes to work that wasn't in the original quote. Without it, the extra is a favour until the invoice arrives and an argument after. Send the authorisation you already write as a link; the client opens it on their phone, approves and signs, and the dated record stays with the job.
What is an extra works authorisation on a domestic job?
On a house extension, a refurbishment or a kitchen, the client changes their mind. They want the socket moved, the wall taken down after all, the tiles swapped for the more expensive ones. None of that was in the quote, so none of it is covered by the contract price. An extra works authorisation is the piece of paper that says what the extra is, what it costs and that the client agreed to it.
The standard domestic forms all have a route for this. The RIBA Domestic Building Contract, the FMB domestic contracts and the JCT Home Owner contracts each set out how the scope can be changed during the job, and where there is an independent contract administrator the instruction comes from them; where there is not, it comes from the property owner.
Who signs is therefore usually the homeowner, and often only one of them. That's where the trouble starts: a nod from one partner at the door isn't the household’s agreement.
What should an extra works authorisation say?
The guidance for builders on getting paid is blunt: extra work should never be carried out without a written price and the client’s approval. The authorisation is short, but it has to be complete enough that nobody can later say they thought it was included.
The price is the part most often left blank, on the promise of sorting it out later. Later is the final invoice, and by then the work is done and the leverage has gone.
- What the extra work is, in plain words, and what it replaces or adds to in the original quote
- The price, or the rate and the estimated quantity, and whether VAT is included
- Any effect on the finish date
- The date and the client’s signature
- A reference so it can be matched to the invoice line later
What goes wrong when extras are agreed on site and never written down?
The extra gets done, the job goes on, and weeks later the final invoice lands with a list of additions the client half remembers agreeing to and doesn't remember agreeing to pay for. Payment is withheld, the relationship sours, and a job that was priced correctly ends up losing money on the extras.
The Federation of Master Builders describes this as a slow leak: not one big dispute, but a dozen small extras that were never priced in writing, each one a discount the builder didn't intend to give. When a dispute does escalate, the documents that count are the signed contract, the approved variations and the photos; a text message saying fine, go ahead is thin evidence, and a conversation in the kitchen is none.
The form isn't the hard part. Getting it signed while the client is at work and you are on site, before the plasterer arrives, is the hard part.
How do I get extras authorised with Portal Worx?
You upload the authorisation, as a PDF or a photo of the sheet, to the job in Portal Worx and send the client a link by email. They open it on their phone at work. No account, nothing to install, nothing to learn: they see the document and are asked to approve or decline.
They can leave a note or ask a question before deciding. If you asked for it, they must enter a one-time code emailed to them before signing, which shows whoever signed had control of that inbox at that moment. Then they draw their signature on the screen and submit.
If nothing comes back by lunchtime, you chase from the same screen. If the price changes after a question, you send a new version; it supersedes the first, and the first stays on the record.
What does the signed record hold?
The record is dated, signed, and pinned to the exact file the client saw, with its SHA-256 fingerprint. The approval, any notes and every version are kept with the job, next to the quote, the photos and the rest of the paperwork.
When the invoice goes out, each extra points at a signed authorisation rather than a memory. A simple electronic signature is admissible evidence in the UK under the Electronic Communications Act 2000; what weight it carries is up to the court and depends on the record around it, which is why the fingerprint, the date and the notes are on it.
Where doesn't this fit?
One request goes to one person. If both homeowners need to sign, you send each of them a request. There's no multiple-approver flow and no passing a request to someone else. The file has to be a PDF, an image or plain text, so a Word authorisation is exported to PDF first.
Portal Worx doesn't price the extra, doesn't write the authorisation, and doesn't check the signer’s identity; the code proves control of an inbox and nothing more. The page opens on our domain, not yours.
Common questions
- Is a signed screen on a phone enough to hold a homeowner to an extra?
- A simple electronic signature is admissible as evidence in the UK. Whether it settles the argument depends on the record: what was signed, when, by which address, and whether the document is provably the same one. That record is what comes back to the job.
- Can I send a photo of a handwritten extras sheet?
- Yes. Images are accepted alongside PDFs and plain text. The client sees the photo, can mark a note on it, and signs against that exact image.
- What if the client asks a question instead of signing?
- The question comes back as a note on the request and you answer it in the same place. If the answer changes the price, send a new version; the client signs the new one and both stay on the record.
- Do I pay per authorisation?
- No. Requests and links are unlimited on every plan, from £29 a month. Plans are cut on the number of projects, storage and AI credits.
- Does the client have to sign up for anything?
- No. They get an email with a link, open it on their phone and sign. No account, no app, no password.
Related
What else Portal Worx does
This page covers one part of it. Behind every request for sign-off is the job it belongs to: projects holding your documents and site photos, with a folder or a file shareable by link to someone with no account; versions with history and an approval pinned to each; reports built on site and exported as a PDF with your logo; threaded messaging; a year-long activity trail; and AI that catches you up on where a job stands without ever seeing more than you can.
See everything it does, or check the plans. Unlimited users and unlimited requests on all of them.
Price the extra, send it, get it signed before you start.
Upload the authorisation and send the link. The client signs on their phone and the record stays with the job. 14 days free, no card, unlimited requests on every plan.