Changes to the works
Understanding variations during building work
A variation is simply a change to what was agreed. Almost every project has some. Variations become a problem only when they are undocumented, priced after the event, or allowed to accumulate until nobody can say what the contract now covers.
What counts as a variation
- You change your mind about a finish, a layout or a specification.
- The builder proposes a different method or product.
- Site conditions require something that was not in the original scope.
- A statutory body, such as building control, requires a change.
- Something in the original scope is removed, which should produce a credit.
Agree it before it happens
This single habit prevents most variation disputes. A variation agreed in advance is a shared decision; the same variation discovered on a final invoice is an argument.
It does not need a formal contract document. A dated email that both sides have is enough for most domestic projects.
What a good variation record contains
- A number or reference, so it can be tracked.
- A plain description of what is changing.
- The reason for the change and who requested it.
- The cost effect, including any credit for omitted work.
- The programme effect, in days or weeks.
- The date and confirmation from both sides.
Watch the cumulative picture, not just each item
Individually reasonable variations can still take a project well past budget. Keep a simple running total: original contract sum, variations agreed to date, revised total. Reviewing that one line monthly is one of the highest-value habits a homeowner can adopt.
How to approve safely when you are unsure
If you cannot assess the technical merit, you can still control the commercial risk. Ask for the cost cap, ask what happens if the assumption turns out to be wrong, and ask whether a smaller, reversible step is possible first.
Case-style example
A typical example
Half way through a loft conversion the homeowner decides to move a door opening by around half a metre. It sounds minor. The builder confirms it affects the stud layout, one radiator position and a section of the electrical first fix.
Because it is priced and dated before the work starts, the homeowner sees the true cost, decides it is still worth it, and there is no dispute later. Had the same change been made verbally and priced at the end, the identical figure would have felt like an ambush.
How The Construction Clinic helps with this decision
The Construction Clinic helps homeowners recognise when something is a variation, understand what a fair record of it looks like, and keep track of the cumulative effect on budget and programme. We help you make the decision; we do not price or approve the work on your behalf.
Common questions
Questions homeowners ask about this
What is a variation in building work?
A variation is any agreed change to the scope, specification, quantity or method of the works set out in your original quote or contract. It can increase or reduce the contract sum.
Does a variation have to be in writing?
For domestic work it is not always a legal requirement, but it should always be a practical one. A dated written record protects both the homeowner and the builder if the cost or programme is later questioned.
Should a variation change the completion date?
Often yes. Additional work usually needs additional time. Agreeing the programme effect at the same time as the cost avoids a later argument about whether the project is late.
What if I remove work from the scope?
You should receive a credit reflecting the labour and materials no longer required. Omissions are variations too and should be recorded in the same way.
How many variations is too many?
There is no set number. The warning sign is not the count but the absence of a running total: if neither side can state the current revised contract sum, control has been lost.
Can a builder carry out a variation without asking me?
Except in genuine emergencies affecting safety, they should seek your agreement first. Work carried out without instruction is much harder for a builder to justify charging for.