Workmanship Warranties Explained: What They Cover and How to Use One
What a builder's workmanship warranty usually covers, when the clock starts, how it fits with your legal rights, and how to make a claim.
The short version
A workmanship warranty is the builder's promise to put their own work right. Knowing what it covers, and for how long, makes it far easier to use.
A workmanship warranty is a written promise from the contractor who did the work to come back and fix defects in that work for a stated period. It usually covers faults caused by how the job was done: poor fixing, poor sealing, poor finishing. It usually does not cover the materials themselves, which normally carry their own manufacturer's guarantee, or damage caused by something else, such as a storm or later work by another trade.
A warranty sits alongside your legal rights, not in place of them. If the work was not done with reasonable care and skill, you have rights under consumer law whether or not a warranty was offered, and a warranty cannot take those rights away.
This guide explains the different kinds of cover you may hold after a building job, what a typical workmanship warranty includes and leaves out, when the clock usually starts, and how to make a claim so it gets dealt with. It is part of our guide to when building work goes wrong. This is general information, not legal advice.
Three kinds of cover
Who stands behind what
After most building jobs you may hold more than one kind of cover. They come from different places and cover different things, so it helps to know which is which before anything goes wrong.
Workmanship warranty
Given by your contractor. Covers defects in the way the work was carried out, for the period written in your paperwork. It is only as good as the contractor's willingness and ability to honour it, which is why the contractor you choose matters as much as the length of the warranty.
Manufacturer's guarantee
Given by the maker of a product, such as a rooflight, a membrane or a window unit. Covers the product failing, not the installation. Some depend on the product being fitted by an approved installer or registered within a set time, so keep the paperwork and check the conditions.
Insurance-backed guarantee
Offered by some contractors, often through a trade body or a specialist insurer. Designed to honour the workmanship guarantee if the contractor stops trading. Cover, conditions and cost vary a great deal, so read what it actually includes rather than relying on the name.
What's usually included
What a workmanship warranty normally covers
The core of any workmanship warranty is simple: if something fails because of how the contractor did the job, they come back and put it right at no cost to you. On a roof, that might be a tile that was never fixed properly, flashing that was poorly dressed, or a leak around a rooflight that traces back to how it was sealed in. On an extension, it might be cracked plaster from poor preparation or a door hung out of true.
Most warranties are written around defects, meaning faults in the work, rather than around results. A warranty does not usually promise that nothing will ever go wrong with the building. It promises that the part the contractor built was built properly, and that they will correct it if it was not.
The wording matters. Look for what counts as a defect, what the contractor will do (repair, replace, or either at their choice), how you should tell them about a problem, and how quickly they aim to respond. A warranty that is one line on a quote, such as "12 months guarantee", is better than nothing, but it leaves a lot open. It is reasonable to ask for more detail before you accept, and our guide to what a building quote should include covers where warranty terms fit in.
Keep the warranty with the rest of your paperwork for the job, not in a separate drawer. When you need it, you will also need the quote that describes the work, the completion date and your payment records.
Reading the terms
Usually covered, and usually not
Every contractor writes their own terms, so check yours. As a general picture, these are the common inclusions and exclusions.
Usually covered
- Faults caused by poor fixing, fitting or finishing
- Leaks traced to how the work was installed or sealed
- Work that does not match what was agreed in writing
- Labour and materials to put the defect right
- Making good the area disturbed by the repair
- Defects that appear within the warranty period
Usually excluded
- Normal wear and tear over time
- Storm, impact or accidental damage
- Parts of the building the contractor did not touch
- Problems caused by later work by someone else
- Damage from a lack of reasonable maintenance
- Product failures covered by a manufacturer's guarantee
How long, and from when
The warranty period and when it starts
There is no single standard length. Warranty periods are set by each contractor and tend to reflect the kind of work. A repair to one part of an older roof may carry a shorter warranty, because the repair can only be as sound as the roof around it. A full replacement is reasonably expected to last far longer, and warranties on larger works tend to be longer to match. Our answer on how long a workmanship warranty lasts goes through the range in more detail.
Most workmanship warranties run from completion, so the date the job was finished matters. Make sure it is written down somewhere: a completion email, a final invoice or a signed-off snagging list all work. If a job finishes in stages, ask whether each stage has its own start date or whether the warranty starts when the whole job is done.
Two other points are worth checking. First, whether the warranty passes to a new owner if you sell the house. Some do, some do not, and some need the new owner to register. Second, whether any conditions apply, such as paying the final balance in full or reporting a defect within a set time of noticing it. Conditions like these are common and usually reasonable, but you need to know about them before you rely on the warranty.
Your legal rights
A warranty adds to your rights
When a business carries out work for you as a consumer, the Consumer Rights Act 2015 requires the service to be carried out with reasonable care and skill. Materials the business supplies as part of the job must be of satisfactory quality, fit for purpose and as described. These rights apply whether or not a warranty is offered.
A trader cannot use a warranty, or any other contract term, to remove or reduce those rights. So if a warranty has run out but the work was never done properly in the first place, you may still have a claim. The time limits for bringing a claim for breach of contract are measured in years rather than months, although they differ between the nations of the UK.
In practice, a warranty is usually the easier route. It sets out a process, the contractor has already agreed to it, and it avoids arguments about whether the work met a legal standard. Your statutory rights are the backstop. Our guide to consumer rights for building work explains them in more detail, and Citizens Advice publishes clear, free guidance. This is general information, not legal advice.
Making a claim
How to use your warranty
A warranty claim goes best when it is clear, early and in writing.
Check your paperwork
Look at the warranty terms, the quotation and the completion date. Confirm that the problem falls within the period and is the kind of fault the warranty covers.
Record the problem
Take dated photographs and short videos, from a distance and close up. Note when you first noticed it and when it appears, for example only in heavy rain. Our guide to keeping evidence and records explains what helps.
Tell the contractor in writing
A short email or letter: what the problem is, where it is, when you noticed it, and that you are asking them to put it right under their warranty. Attach the photographs.
Agree a visit
Ask for an inspection date. Be reasonable about access and timing, and keep a note of what is said on the day.
Get the fix confirmed
Once the repair is done, ask the contractor to confirm in writing what was done, and whether the repair carries its own warranty or falls under the original one.
Escalate if it stalls
If the contractor does not respond or refuses, follow a clear complaint process. Our guide to raising a complaint with a builder sets out the steps.
If a defect is causing damage, such as water coming in, you can take reasonable steps to stop it getting worse before the contractor arrives. Photograph everything first, keep any temporary measures simple, and tell the contractor what you did. Avoid having the original work stripped out or redone by someone else before the contractor has had a chance to see it, as that can make a warranty claim much harder.
Before you sign
Questions to ask about a warranty up front
The best time to understand a warranty is before you accept the quote, when a contractor is keen to answer. Ask how long the workmanship warranty runs and from when, what it covers and excludes, and whether you will receive it in writing.
Ask whether any products carry a separate manufacturer's guarantee and who registers it. Ask whether the warranty passes to a new owner. If an insurance-backed guarantee is offered, ask who provides it and what would trigger it. Our guide to trade accreditation schemes explains how some schemes approach guarantees.
Then compare warranties as part of comparing quotes. A longer warranty from a contractor who is hard to reach may be worth less in practice than a shorter one from a contractor who answers the phone and comes back when asked.
If you use Mortaro
Where the warranty sits when we coordinate your project
Mortaro coordinates domestic building projects. We appoint a contractor from our network, arrange the site visit, prepare your quotation, and handle the communication and payment administration from there. The work is carried out by an independent main contractor who is named in your quotation. Your contract for the work is with them, and so is the warranty.
Every contractor in our network agrees to a minimum 12-month workmanship warranty, usually running from completion, and warranties on larger works are typically longer. The exact terms are set by your contractor and confirmed in your quotation. Because the warranty is the contractor's, it depends on the contractor continuing to trade. We do not guarantee or insure the work ourselves.
What we do is escalate. If something covered by the warranty needs putting right, tell us and we raise it with your contractor, push for a visit and keep you updated. Contractors who fail to put their work right are removed from our network. Putting things right explains how that works, and how quotations work shows where the warranty terms appear.
Straight answers
Questions about workmanship warranties
Is a verbal warranty worth anything?
It can be, but it is hard to rely on. What a trader tells you can form part of the contract if you took it into account when deciding to go ahead, but proving what was said is difficult. Ask for the warranty in writing, even if it is a short email.
Does a workmanship warranty cover materials?
It covers how the work was done. Products usually carry a separate manufacturer's guarantee. If a product was fitted badly, that is usually a workmanship issue. If it failed on its own, it is usually a product issue, and the contractor may help you make that claim.
What if I held back part of the final payment?
Check your terms, as some warranties only apply once the job is paid in full. If you held money back because of an unresolved problem, keep a written record of why. Our guide to final payment and snagging covers this.
What happens to the warranty if the contractor stops trading?
A warranty from a business that has closed is usually difficult or impossible to enforce, unless it is insurance-backed. Our guide to when a contractor goes out of business explains what you can still do.
Can another builder's work affect my warranty?
It can, if another trade alters or disturbs the warranted work. If you need other work done nearby, check your terms first and let the original contractor know.
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