UK SIC 2007 · 41100
Development of building projects (SIC code 41100)
UK property developers use this code. They buy land, run the build, then sell or keep the finished building. It takes in housing developers building on spec as well as commercial and mixed-use firms.
Division 41: Construction of buildings
Division 41 is one of the most used classifications on the UK register. It splits three ways. Code 41100, development of building projects, is picked by developers and by companies set up to hold one scheme. Then come the two building codes. Code 41202 covers domestic construction, so house builders and residential contractors live there. Code 41201 covers commercial buildings. The developer code is popular partly because property investors use it for their ventures. So plenty of 41100 companies employ no tradespeople at all.
Related SIC codes
Who prospects SIC 41100 companies
The construction supply chain sells into this division from every side. Builders' merchants and tool hire firms want trade accounts. Insurance brokers arrange contract works and liability cover. Accountants untangle CIS and the VAT reverse charge. Software firms sell estimating and project tools. Development finance brokers and lenders focus on 41100 incorporations, which often come just before a land purchase. Under 41202, a new company usually means a sole trader has gone limited. That is the best moment for accountancy and insurance offers. Growth signals mean bigger projects and a bigger materials spend.
Lead generation for trades & construction →How to read SIC 41100
SIC 41100 is a five-digit code, and the digits are not arbitrary. The first two, 41, are the division, construction of buildings. Add the third and you have group 411; the fourth narrows it to a class, and the fifth to the subclass, which is the level Companies House actually asks a company to pick. The whole division sits under section F, construction, the broadest tier there is. Reading a code left to right therefore goes from a whole sector down to one activity.
A company chooses its own codes when it incorporates and can change them on any confirmation statement. It may list up to four, and Companies House does not check whether they are right. That is why 41100 is worth reading as a claim the company made about itself rather than as a verified fact, and why the first-position and any-position counts above differ.
Measured on the August 2026 register, the busiest registered-office post towns for 41100 are London (20,224), Manchester (1,729), Birmingham (1,337), Bristol (1,254), Leeds (1,036). Those are registered-office locations, which is where the paperwork sits rather than necessarily where the work happens, so treat them as where to start looking rather than as a service area.
Using SIC 41100 as a filter
109,402 companies is 2.1 per cent of the 5,190,464 active companies on the UK register, and ranks 41100 most used of the 3 codes we track in division 41. That is the pool before any filter. Whether it is a big market for you depends on what you sell, but it is the number every other filter on this page cuts down from.
Almost everybody who uses 41100 means it: 108,180 of 109,402 companies put it first, leaving only 1,222 carrying it as a secondary code. That makes it an unusually clean filter. You can match on the code alone and trust that the companies you get really are in this line of work.
These companies are spread out. London is the largest single cluster at 18 per cent and the top five post towns together hold only 23 per cent, so the remaining 77 per cent sits across the rest of the country. A regional filter narrows this list without gutting it, which makes it a reasonable code to work territory by territory.
In practice the code on its own is rarely the whole filter. Pair 41100 with an incorporation date to catch companies in their first months, when they are still choosing suppliers, or with a filing deadline to reach them while the year end is on their mind. A worked example for this code: 41100, registered office in London, incorporated in the last ninety days, which turns a 109,402 company pool into a list you can write to in an afternoon. Add the poor-website filter if what you sell is a website, or a recent change of officer if you sell to whoever just took the job. 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.
Where SIC 41100 clusters in the UK
ACTIVE COMPANIES BY REGISTERED-OFFICE POST TOWN · COMPANIES HOUSE REGISTER, AUGUST 2026
SIC 41100 companies, as leads
Live rows from the enriched register. Email and phone values are withheld until you sign up.
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About SIC 41100
How do I tell SIC 41100 developers from contractors?
Developers buy the land and run the project. Contractors (41201, 41202) do the building. A pure developer hands the build to one of them. Many developer ltds file both codes anyway.
Why are so many SIC 41100 companies sole-director?
Most UK schemes get their own company, one per project. That ring-fences the financial risk. This single-purpose vehicle (SPV) usually has one director, the developer. When you build a list, aim at the parent company rather than the SPVs.
Find UK SIC 41100 companies
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