How Renovation Notes Prices Its Figures

Every price on this site is built the same way, from the same set of books, and every one of them is a ballpark. This note explains how the figures are made, where they are checked, and what the confidence level attached to each one means for how far you should trust it.

The short version: we price materials from merchants’ own list prices, labour from published labour times and trade day rates, and installed work by adding the two, then check the result against prices published by other people, including the official rating cost guides. None of that turns a figure into a quote. In the terms of how cost estimates work, every figure here sits at the first level: a cost-guide ballpark.

Five Books, One Source for Every Figure

Every cost figure on the site traces to one of five books:

The UK Renovation Cost Index gathers the headline ranges from these books in one place, with the basis of each.

The Method We Follow

The books follow the procedure of a published construction estimating manual used by the US Navy, Army and Marine Corps, approved for public release. It breaks a job into work elements, each usually one trade doing one task, and makes a separate estimate of the materials, the plant and the labour for each element.¹

Materials are measured as a net quantity, and an allowance for waste is added for each type of material to give the quantity bought.¹ Labour is always worked out on the net quantity, never on the waste.¹

Every price assumes normal conditions. Known conditions, such as poor access, a home that is lived in during the work, an old building that is out of true or a premium finish, scale the labour task by task, never as one figure on the whole job.¹ The estimate builder lets you set these conditions line by line.

Each whole-job price is also checked against a list of general items, such as waste removal, scaffolding, protection, consents and making good, so it is clear what the price includes and what it leaves out.¹

The manual’s labour figures are for military crews, and the manual itself puts civilian work at 1.33 to 2 times their pace.¹ We use them only as a cross-check where they agree with UK figures, never to lower a UK figure on their own.

Materials

Materials are priced at the merchant’s list price: the price on the merchant’s own product page for the actual product, never a category listing or a search result. The books hold that price ex VAT, because trade counters and merchant accounts work ex VAT and it keeps every figure on one basis. VAT at the standard rate of 20% is then added where the homeowner pays it.² The notes usually show the VAT-inclusive figure where that is what you would pay, and our note on reading a builders’ merchant quote explains why the same item can carry two prices 20% apart.

A list price is not the best price. Builders with accounts, and anyone buying a full load, usually pay less; anyone buying a single bag usually pays more. We use the list price because it is published and anyone can check it, which a negotiated price is not.

Labour

Labour has two parts: how long the work takes, and what an hour costs.

Time comes from published labour times, the hours a gang takes to lay a square metre or fit an item, taken from labour constants, schedules of rates and manufacturers’ fitting instructions. Day rates start from pay statistics, chiefly the Office for National Statistics’ Annual Survey of Hours and Earnings, which reports earnings and hours by occupation.³ They are cross-checked against agreed industry rates and against labour-only and charge-out rates that firms publish. Our note on what an hour of labour actually costs shows why the wage is only the start of it.

On top of the wage go the costs of running a business: time that is not spent on the tools, overheads, and profit. Overheads and profit are added once, so materials are not marked up twice when they go into an installed price.

Small jobs carry extra overhead

A one-hour job costs a builder much the same in travel, parking, setting up, the van and the office as a full day does. So a per-item job that takes less than a day carries an extra overhead, at its fullest up to half a day and tapering to nothing at a full day. Prices per metre or per square metre are never loaded this way, and an item priced inside a larger job does not carry its own loading. Our note on the costs that only small jobs carry explains the wider problem.

Installed Prices, and How We Check Them

An installed (supply and fit) price is built from its parts: the materials with an allowance for waste, the labour, any plant, and overheads and profit. Each is then checked against prices observed elsewhere: firms’ published installed prices, cost guides and the official rating cost guides. Where the built-up price and the observed prices disagree, the figure is graded down until the disagreement is explained.

The official guides are the Valuation Office Agency’s and the Scottish Assessors’. The Valuation Office Agency’s Rating Cost Guide 2026 prices building work for business rates valuations, built up from actual build costs and industry price books.⁴ The Scottish Assessors Association publishes a parallel Rating Cost Guide Scotland 2026.⁵ They are official, published schedules of building costs, and they come with limits that we respect.

• They are set at a fixed date. The VOA guide’s costs are set at 1 April 2024, the valuation date for the 2026 revaluation.⁴ A figure checked against them has to allow for price movement since, which our note on bringing an old building price to today’s money explains.
• They are struck for large contracts. The VOA’s costs are adjusted to the price level of a £4 million contract at a national average location.⁴ A domestic job is far smaller and costs more per unit, for the reasons in why a published building rate is not what you pay.
• They are not written for this. The VOA says the guide is for rating valuations only and must not be used for any other purpose.⁴ We use the rating guides only as an independent check on the level and shape of an installed price, never as the price of your job.

Grants Are Shown Beside the Price, Never Taken Off It

Prices for grant-eligible work, such as heat pumps and biomass boilers, are always shown before the grant, with the grant in brackets beside them. Not every home qualifies, grant amounts change, and a price after grant hides what the installer is actually charging.

The Boiler Upgrade Scheme currently gives £7,500 towards an air source or a ground source heat pump.⁶ Until March 2027 there is an extra £1,500 for homes heated by oil or LPG with no mains gas connection.⁶ The grant is taken off what you pay the installer and shown on the quotation and invoice.⁷ RICS NRM 1 takes the same line for professional estimates, recommending that grants are left out of an order of cost estimate.⁸ Our guide to the Boiler Upgrade Scheme covers eligibility.

Five Confidence Levels

Every figure in the books carries one of five confidence levels. The level describes the source and how well it has been checked, not how close the figure will be to your quote.

A few rules sit behind the levels. A price more than two years old drops a level. Labour-only and installed prices are computed, so they are level 3 at best, and an installed price takes the weighted level of the lines in it. Day rates are worked out from pay statistics and published rates, so they are level 2 at best.

How the Levels Relate to Estimate Accuracy

Confidence and accuracy are different questions. Confidence asks whether a figure is a true statement of what its sources say. Accuracy asks how close it will be to what you end up paying, and that depends on how well your own job is defined.

A level 1 figure from an official guide is a faithful copy of an official number, and it is still a ballpark for your house, because nobody has measured your house. The published accuracy ranges for that level of estimate, set out in how cost estimates work, apply to every figure here, whatever its confidence level. A higher level narrows the risk that the figure is simply wrong; it does not narrow the risk that your job is different.

So use the site’s figures to test whether a project is affordable, to set a first budget with a contingency, and to ask sharper questions of a quote. When a builder’s price is far from ours, the likeliest explanation is a difference in scope, specification, access or region, and it is worth finding out which before deciding who is right.