Most construction companies assume R&D tax credits are for tech firms, pharmaceutical labs, or aerospace engineers. That is wrong. If you are a construction company developing new materials, testing innovative building methods, or solving site-specific technical problems, you could qualify for a significant corporation tax reduction or cash repayment.

HMRC's definition of R&D is broader than most business owners realise. It covers projects that seek to achieve an advance in science or technology. That advance does not need to be world-first. It needs to be a genuine advance in your field, or in the specific context of your industry, that could not be readily worked out by a competent professional in your sector.

This guide explains r&d tax credits explained specifically for construction companies working on new materials. We cover what qualifies, what costs you can include, and how to prepare a claim HMRC will accept without a fight.

What Qualifies as R&D in Construction Materials?

HMRC's guidelines are clear. A project qualifies as R&D if it seeks to achieve an advance in science or technology by resolving scientific or technological uncertainty. The key question is: did you have to overcome a genuine technical problem that a competent professional in your field could not solve using standard practice?

For construction companies developing new materials, qualifying activities often include:

  • Developing a new concrete mix with specific performance characteristics (higher strength, lower carbon, faster curing)
  • Creating composite materials that combine properties not available in existing products
  • Testing novel insulation materials for thermal performance and fire resistance
  • Developing coatings or sealants that perform in extreme conditions
  • Creating new methods for bonding, fixing, or joining materials that do not exist in current practice
  • Designing and testing new formwork or moulding systems for bespoke material shapes

The advance must relate to the materials themselves, not simply to using an existing material in a new location. If you are the first company in the UK to use a specific German-manufactured polymer in a UK climate, that is unlikely to qualify unless you had to overcome technical uncertainty to adapt it for UK conditions.

Real Example: A Manchester Construction Firm's R&D Claim

A Manchester-based construction company specialising in heritage restoration needed a new mortar mix that matched the appearance and breathability of 18th-century lime mortar but met modern building regulations for thermal performance and compressive strength. No off-the-shelf product existed. They spent 14 months testing over 40 different mix ratios, developing a custom binder, and commissioning independent testing for thermal conductivity and vapour permeability.

That project qualified for R&D tax credits. The total qualifying expenditure was £187,000 across staff time, materials, subcontractor testing, and software licences for thermal modelling. The company received a corporation tax reduction of £46,750 plus a cash repayment of £12,400 because they were loss-making on that project.

What Costs Can You Include in an R&D Claim?

For a construction company developing new materials, the most common qualifying costs fall into these categories:

Staff costs. Salaries, employer NI, and pension contributions for employees directly involved in the R&D activities. This includes site managers supervising material testing, laboratory technicians running samples, and directors overseeing the technical development. Time must be recorded or estimated on a reasonable basis.

Materials. Raw materials consumed or transformed during the R&D process. If you ordered 5 tonnes of a special aggregate for testing and used 3.7 tonnes in trials, the cost of that 3.7 tonnes qualifies. The remaining 1.3 tonnes used in production does not.

Subcontractors. If you engage external specialists to help with the R&D, their costs can qualify. This is common when construction companies work with materials science labs, university engineering departments, or specialist testing houses. The rules differ depending on whether the subcontractor is connected to your company.

Software licences. The proportion of software licence costs used directly for R&D. If you use a thermal modelling package 60% of the time for R&D and 40% for routine design work, 60% of the licence cost qualifies.

Consumables. Items used up in the R&D process. Fuel for testing equipment, protective gear used exclusively in the testing area, calibration gases for analysers. These must be directly consumed in the R&D activity.

Externally provided workers. Agency staff or contractors working under your supervision. Their costs qualify but at a reduced rate (65% of the cost).

The Two R&D Schemes: Which One Applies to You?

From accounting periods starting on or after 1 April 2024, the R&D tax credit system operates under a merged scheme for most companies. The old distinction between the SME scheme and RDEC (Research and Development Expenditure Credit) for larger companies has been replaced by a single RDEC-like scheme for most claimants.

However, there is an important exception for loss-making companies that are R&D-intensive. If your company spends at least 30% of its total expenditure on qualifying R&D, you may be able to use the enhanced R&D Intensive Scheme (ERIS). This allows you to surrender losses for a cash repayment at a higher rate.

For a typical construction company developing new materials, the applicable scheme depends on your company size and R&D intensity:

  • Companies with fewer than 500 employees and either turnover under €100M or a balance sheet under €86M are SMEs for R&D purposes
  • Profit-making SMEs can claim a 19% payable tax credit (effectively reducing corporation tax)
  • Loss-making SMEs with R&D intensity above 30% can claim ERIS for a cash repayment of up to 27% of qualifying costs
  • Loss-making SMEs below the 30% threshold can claim the RDEC-style credit at 15%
  • Large companies (above the SME thresholds) claim under the full RDEC scheme at 15%

These rates are for the 2025/26 tax year. The exact figures change periodically, so check the current rates with your accountant before submitting a claim.

Common Mistakes Construction Companies Make on R&D Claims

HMRC scrutinises R&D claims more closely than they did five years ago. The number of claims has risen sharply, and HMRC has responded with more detailed compliance checks. Construction companies are particularly vulnerable to these common errors:

Confusing innovation with R&D. Using a new material that someone else developed is not R&D. Developing that material yourself is R&D. If you bought an off-the-shelf high-performance concrete from a supplier, that is procurement, not R&D.

Including routine testing. Quality control testing of standard materials does not qualify. Testing a new material formulation to see if it meets your specification does qualify. The distinction is whether the outcome was uncertain at the start.

Poor time recording. HMRC expects to see some evidence of how staff time was allocated to R&D activities. A retrospective estimate based on memory is weak. A spreadsheet tracking time against specific R&D projects is much stronger. Even a director's note explaining the basis of the estimate is better than nothing.

Missing subcontractor costs. If you paid a university materials lab to test your new composite, that cost qualifies. Many construction companies simply expense these as general professional fees and miss the R&D claim entirely.

Overlooking capital allowances interaction. If you bought equipment specifically for R&D, you may be able to claim both capital allowances and the R&D tax credit on the same asset. The rules are technical, but the combined benefit can be significant.

How to Prepare an R&D Claim for HMRC

A strong R&D claim starts with good documentation, not with a tax return. HMRC's R&D tax credit guidance requires you to explain the technical uncertainty you faced, the advance you sought, and the work you did to overcome the uncertainty. For a construction company developing new materials, this typically means preparing:

  • A technical narrative describing the project, the problem, and why it could not be solved using standard practice
  • Supporting evidence such as test results, design iterations, project meeting notes, and correspondence with suppliers or specialists
  • A cost breakdown showing qualifying expenditure by category
  • A time allocation methodology explaining how staff hours were estimated

You must submit the claim as part of your company tax return (CT600). You do not file a separate R&D form, though HMRC may ask for additional information using the R&D Additional Information Form (AIF) after you submit.

Claims can be made up to two years after the end of the accounting period. For a company with a 31 March year-end, you have until 31 March of the second following year to amend your return and include the R&D claim. Do not leave it that late. The longer you wait, the harder it is to reconstruct the evidence.

Real Numbers: What a Construction R&D Claim Looks Like

Consider a Birmingham construction company with a 31 December year-end. They spent 18 months developing a new lightweight aggregate panel for use in high-rise residential projects. The qualifying costs were:

  • Staff costs (project manager, two technicians, director oversight): £94,500
  • Materials (aggregate samples, binders, testing materials): £38,200
  • Subcontractor testing (university materials lab): £22,600
  • Software licences (thermal and structural modelling): £7,800
  • Consumables (protective gear, calibration gases, sample preparation): £3,200

Total qualifying expenditure: £166,300. The company was profitable, so the R&D tax credit reduced their corporation tax liability by £31,597 (19% of £166,300). That is £31,597 they would not have received without the claim.

If the same company had been loss-making and R&D-intensive (R&D spend above 30% of total expenditure), they could have surrendered the losses for a cash repayment of approximately £44,900 using ERIS.

When to Speak to an Accountant About an R&D Claim

If your construction company has spent money developing new materials in the last two accounting periods, you should speak to an accountant who understands both construction and R&D. The claim requires technical justification and accurate cost allocation. Get it wrong and you face a compliance check, repayment of the credit, and potential penalties.

Our ICAEW qualified team at Holloway Davies works with construction companies across the UK. We have helped clients in Manchester, Birmingham, Bristol, and London prepare R&D claims for new materials, innovative building methods, and site-specific technical solutions. Contact us to discuss whether your project qualifies.

If your company turnover is below £90,000 and you are not yet VAT registered, check whether voluntary registration makes sense for your R&D material purchases. Our VAT guide covers the calculation.

For companies considering incorporation, the structure you choose can affect how R&D claims are handled. Read our incorporation guide for the full picture.

Final Thoughts

R&D tax credits are not just for Silicon Roundabout startups. Construction companies developing new materials are exactly the kind of business the scheme was designed to support. The UK needs better building materials: lower carbon, higher performance, longer lasting. If your company is doing that work, the tax system should reward you for it.

The key is preparation. Document your technical uncertainty, track your costs, and submit a claim that tells a clear story of genuine R&D. Do that, and the corporation tax saving is yours.