Civil engineering (SIC division 42)
Division 42 of the UK SIC 2007 list. It holds 7 codes, listed in full below with the number of active UK companies filed under each.
What sits in division 42
Civil engineering is about infrastructure, not buildings. Roads sit under 42110 and railways under 42120. Utility networks for power and telecoms use 42220. The broad code 42990 covers other civil projects, and it is the division's most used UK code. That catch-all holds groundworks and infrastructure contractors. Their work spans drainage, foundations, flood defences and external works. Companies range from national contractors down to small civils firms serving housebuilders. Subcontracting chains run deep here, so much of the public record is specialist subcontractors.
Plant is at the heart of selling to civils firms. Hire companies, excavator and attachment dealers, fuel suppliers and operator training providers all work this division hard. They watch for growth, because growth means a bigger fleet. Recruiters supplying operators and site engineers follow the same signals, as do insurance brokers and surety bond providers. Civils work comes from frameworks and tenders. So a new company often means a management team has spun out to chase one contract. They need bonds, accreditation and plant right away. Utility contractors under 42220 buy in step with fibre and grid investment cycles.
How to read a division 42 code
A UK SIC code is five digits and division 42 is the first two of them. Everything filed under 42 shares those digits: all 7 codes below begin 42, then the third digit narrows to a group, the fourth to a class and the fifth to the subclass a company actually picks. Division 42 sits inside section F, construction, which is the broadest tier of the classification. So a code is read left to right, from an industry down to a specific activity.
More on how division 42 codes are built
Companies choose their own codes at incorporation and can change them on any confirmation statement, and Companies House does not check the answer. A company may list up to four. That is worth knowing before you treat any division total as a headcount: the numbers here are what companies said about themselves, on the August 2026 register, and the largest single code in this division is 42990, construction of other civil engineering projects n.e.c..
Working division 42 as a list
Division 42 holds 7 codes and 32,926 active companies between them. One code carries most of it: 42990 accounts for 54 per cent on its own, and the top three take 82 per cent, with the rest spread across the remaining 4 codes. Filtering by the whole division is therefore close to filtering by 42990 with a tail attached, so start from the code and widen only if the list runs dry.
More on working division 42
A caveat that matters more in some divisions than others: a company may register up to four SIC codes, and the figures below count every position, not just the first. A business filed under two codes in this division appears under both. Treat the totals as reach rather than a headcount, and if you need a clean list, filter to companies whose FIRST code sits in the division. Every company you pull carries the Companies House record, the director's name, a verified website and a verified email, and the ones we cannot complete are not charged.
Every SIC code in division 42
42110, Construction of roads and motorways42120, Construction of railways and underground railways42130, Construction of bridges and tunnels42210, Construction of utility projects for fluids42220, Construction of utility projects for electricity and telecommunications42910, Construction of water projects42990, Construction of other civil engineering projects n.e.c.Prospecting this division
Division 42 companies, as leads
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Division 42 questions
Is groundworks a division 42 or division 43 activity?
Both codes exist and the split is genuinely fuzzy. Site preparation and excavation is 43120. Broader civil engineering work fits 42990. Many groundworks contractors choose 42990, because their scope covers drainage, roads and structures. Others use 43120 for enabling works. Listing both is common and allowed within the four-code limit. Nothing is enforced on the choice. It is a self-declared classification.
Can one company hold codes across construction, civil engineering and plant hire?
Yes. Companies House allows up to four SIC codes and does not restrict which divisions they come from. A contractor doing building work, civils and equipment hire can list codes from divisions 41, 42, 43 and 77 at the same time. You set codes at incorporation on the IN01, and change them on the CS01 confirmation statement. There is no approval step. Updates take effect once the statement is filed.
Find companies across division 42
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