UK SIC 2007 code in Section F: Construction

43999 Other specialised construction activities n.e.c.

SIC 43999 is the UK code for other specialised construction activities n.e.c., part of the class "other specialised construction activities nec". Companies House accepts it when you register a company or file a confirmation statement.

Code
43999 (UK SIC 2007, Companies House list)
Section
Section F: Construction
Division
43 Specialised construction activities
SIC 2026
42.99 Construction of other civil engineering projects n.e.c. (1:10); 43.22 Plumbing, heat and air-conditioning installation (1:10); 43.23 Installation of insulation (1:10); 43.35 Other building completion and finishing (1:10); 43.41 Roofing activities (1:10); 43.91 Masonry and bricklaying activities (1:10); 43.99 Other specialised construction activities n.e.c. (1:10); 43.42 Other specialised construction activities in construction of buildings (1:10); 43.50 Specialised construction activities in civil engineering (1:10); 81.22 Other building and industrial cleaning activities (1:10)
Closest US NAICS
236210, 238110, 238120, 238130 and 6 more

Activities ONS lists under 43999

The ONS index assigns these 57 activities to this code. If one describes your company, this is the code to use.

Source: ONS UK SIC 2007 alphabetical index.

Businesses that use this code

What changes in SIC 2026

ONS published UK SIC 2026 in 2026. Its correspondence table maps this code's class (43.99) to:

SIC 2026 codeHeadingLink type
42.99Construction of other civil engineering projects n.e.c.1:10
43.22Plumbing, heat and air-conditioning installation1:10
43.23Installation of insulation1:10
43.35Other building completion and finishing1:10
43.41Roofing activities1:10
43.91Masonry and bricklaying activities1:10
43.99Other specialised construction activities n.e.c.1:10
43.42Other specialised construction activities in construction of buildings1:10
43.50Specialised construction activities in civil engineering1:10
81.22Other building and industrial cleaning activities1:10

"1:1" means the class carries over unchanged in scope; other link types mean it was split or merged. Companies House still uses SIC 2007, so keep filing with 43999 until it announces a switch.

Source: ONS correspondence table, SIC 2007 to SIC 2026.

Closest US NAICS codes

Matched through the shared international class (ISIC Rev. 4). Treat these as a starting point and read the definition before using one.

Similar codes to compare

Data last changed November 14, 2026. Source: Companies House condensed SIC list. How this page is built.