Home Renovation Insurance: What You Need During a Build

Most homeowners starting a renovation assume their existing buildings and contents insurance will cover anything that goes wrong during the build. In almost every case, it will not. Standard home insurance policies contain clauses that exclude or void cover when the property is undergoing significant building works — and the consequences of being uninsured during a renovation can be catastrophic. This guide explains the three policies you actually need, what your contractor should hold, and the specific risks that catch homeowners out.

Why Standard Home Insurance Does Not Cover a Renovation

A standard home insurance policy is priced on the basis of a property in normal residential use. When you start building works, several things change that fundamentally alter the insurer's risk:

• The structure is partially open to the elements (roof off, walls open)
• Non-resident workers and subcontractors are on site daily
• Building materials and plant are being stored on the property
• The property may be unoccupied for extended periods
• The risk of fire, flood, vandalism, and theft increases substantially

Many policies contain a clause that voids cover entirely if the property is left unoccupied for more than 30 or 60 days. A renovation that requires you to move out — even temporarily — can trigger this exclusion immediately. Crucially, even if you remain living in part of the property, most insurers class significant building works as a material change of risk and require you to notify them. Failure to notify can void your policy.

Contact your insurer before any significant building works begin. In most cases they will confirm in writing that the cover is inadequate for your needs, at which point you need specialist renovation cover.

The Three Policies You Need

1. Contract Works Insurance (Site Insurance)

Also known as all-risks insurance for the works, contract works insurance covers the building under construction against damage — including fire, flood, storm damage, vandalism, and theft of materials on site. It covers both the existing structure (which can be damaged during renovation) and the new works themselves.

If you are employing a main contractor, check whether their contract works policy covers the entire project including your existing property, or only the new works. Some contractors' policies cover the works they are constructing but not the existing structure — leaving you exposed for accidental damage to the original building. This needs to be confirmed in writing before work starts.

If you are self-managing with direct labour, you will almost certainly need to take out your own contract works policy.

Typical cost: £500–£2,000 for a full renovation of a residential property, depending on the total rebuild value, duration, and location. Premiums are higher for properties in flood risk areas, high-crime postcodes, or where the property will be fully unoccupied.

2. Public Liability Insurance

Public liability (PL) insurance covers claims from third parties — neighbours, members of the public, or visitors — for injury or property damage caused by your building works. If a scaffold pole falls and damages a neighbour's car, or a visitor trips over materials on site and breaks a wrist, public liability insurance covers the legal costs and any damages awarded.

Your main contractor should hold public liability insurance as a condition of appointment. The minimum acceptable limit for residential renovation work is £2 million, though £5 million is preferable for larger projects. Request the insurance certificate before work starts, check the expiry date, and confirm the limit.

If you are self-managing and acting as the client-employer, you may need your own PL policy as a separate layer. Some contract works policies include a combined PL element — check the schedule carefully.

3. Employer's Liability Insurance

If you are directly employing anyone to work on your property — including labour-only subcontractors who supply their time but not materials — you are legally required to hold employer's liability (EL) insurance under the Employers' Liability (Compulsory Insurance) Act 1969. The minimum legal limit is £5 million, though most policies provide £10 million as standard.

This requirement catches many self-managing homeowners by surprise. A labour-only bricklayer, carpenter, or labourer who provides their services (rather than supplying a finished product) may be considered a worker for legal purposes, even if they are self-employed and invoicing as a sole trader. If that person is injured on your site and you do not hold EL insurance, you are personally liable for the full cost of any compensation claim.

If all your contractors supply their own materials and are genuinely running their own businesses (with their own tools, multiple clients, and their own insurance), the risk is lower — but obtain legal advice if you are uncertain.

Unoccupied Property Insurance

If your renovation requires you to vacate the property, standard home insurance will typically lapse after 30 to 60 days of unoccupancy. You will need to arrange specific unoccupied property insurance, which is available from specialist brokers including Adrian Flux, Aviva, and Zurich. Expect to pay a premium of 10–25% above standard home insurance rates, with reduced cover (fire, lightning, explosion, and aircraft only — not storm, flood, or escape of water) under some policies.

Before exchange of contracts on a property you are buying in a poor state, confirm with your solicitor and insurer who bears the risk of loss between exchange and completion. Standard conveyancing practice in England and Wales places risk on the buyer from exchange — so you are responsible for insuring a property you do not yet have the keys for.

Structural Warranty Requirements

If your renovation involves a substantial conversion — a barn conversion, a basement excavation and fit-out, or a change of use from commercial to residential — most mortgage lenders will require a 10-year structural warranty as a condition of lending. This applies even if the conversion is carried out to building regulations standard with a Completion Certificate.

Structural warranties for conversions and renovations are available from Buildstore, Premier Guarantee, LABC Warranty, and NHBC Buildmark (via approved contractors). Costs vary depending on build value and property type, but expect £1,500–£5,000 for a typical residential conversion. Note that an NHBC Buildmark warranty requires the work to be carried out by an NHBC-registered builder — it is not available retrospectively or for DIY builds.

How to Check Your Contractor's Insurance

Do not simply take your contractor's word that they are insured. Before work starts:

1. Request the current insurance certificate(s) for public liability, employer's liability, and contract works cover
2. Check the expiry date — policies renewed annually can lapse mid-project
3. Check the indemnity limit — £2 million minimum for PL; £5 million minimum for EL
4. Check the named insured — ensure it matches the trading name on your contract
5. Contact the insurer directly if you have any doubt about the certificate's authenticity

For related reading on renovation risk and finance:

• Home Insurance During a Renovation UK: What Your Policy Won't Cover — why standard home insurance may be void during a renovation and the 5-point checklist before work starts
• Getting a Mortgage on an Uninhabitable Property in the UK — specialist lenders, bridging finance structure, and a full cost table for a typical £150,000 bridging loan
• How to Project Manage a Home Renovation in the UK — pre-build planning, trade sequencing, variation discipline, and CDM 2015 thresholds