- Company number
- 10512350
- Incorporated
- 6 Dec 20169 years trading
- Registered office
- F6 & F7 Epic House F6 & F7 Epic House, 18 Darnall Road, Sheffield, S9 5AA
- Nature of business
- Construction of commercial buildings
Assix Limited is a 9-year-old private limited company registered in Sheffield, company number 10512350, one of 442 building contractors in Sheffield. Its next accounts are due at Companies House on 31 March 2027, and the CT600 for the period to 30 June 2026 is due at HMRC on 30 June 2027.
Key dates
Worked out from the year end and filing history on the Companies House register.
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Finances
From each year's balance sheet filed at Companies House. Small companies do not have to publish turnover or profit, so these are balance sheet figures.
- Net assets up £1,090 (+0.1%) on the year before, to £981K.
- Net assets rose in 7 of 7 year-on-year comparisons on record.
- Current assets of £1.8M against £995K owed within a year: 1.8 times cover.
- 5 employees on average during the year.
- Balance sheets on record for 8 years, 2017 to 2025.
Net assets by year
| Year end | Net assets | Cash | Current assets | Owed within a year | Employees |
|---|---|---|---|---|---|
| 30 Jun 2025 | £981K | £796K | £1.8M | £995K | 5 |
| 30 Jun 2024 | £980K | £1.1M | £1.7M | £686K | 5 |
| 30 Jun 2023 | £940K | £1.2M | £2.1M | £1.1M | 5 |
| 30 Jun 2022 | £512K | £574K | £1.3M | £770K | 5 |
| 30 Jun 2021 | £261K | £1.5M | £1.2M | 5 | |
| 31 Dec 2019 | £140K | £320K | £180K | ||
| 31 Dec 2018 | £105K | £278K | £173K | ||
| 31 Dec 2017 | £55K | £224K | £169K |
Public contracts won
Assix Limited has 30 public sector contract awards on record; the ones with their own published value total £14M, from 2019 to 2026. Source: Contracts Finder and Find a Tender award notices.
Awards by year
Main buyers
- University of Sheffield29 awards
- Chesterfield Borough Council1 award
| Buyer | Contract | Value | Awarded |
|---|---|---|---|
| University of Sheffield | 5051/EFM/RH - Edgar Allen House, IT Alterations | £689K | 19 Aug 2026 |
| University of Sheffield | 4850.EFM.SW.25 - Solly Street Interior Fit Out and Refurbishment | £1.2M | 28 Nov 2025 |
| Chesterfield Borough Council | Chesterfield Market Hall Roof Repair | 21 Jul 2025 | |
| University of Sheffield | 4287.EFM.JR.24 Arts Tower Steps and Ramp Refurbishment | £585K | 11 Mar 2025 |
| University of Sheffield | 4356.EFM.JR.24 - 9 Mappin Refurbishment Scheme | £251K | 5 Feb 2025 |
| University of Sheffield | 4079.EFM.JR.24 - University Arms External Envelope Works | £332K | 7 May 2024 |
| University of Sheffield | 3974.EFM.JR.23 - 36-38 Victoria Street and University Health Centre Refurbishment | £618K | 8 Mar 2024 |
| University of Sheffield | 3779.EFM.SW.23 Western Bank Library Phase 2 - Level 6 Refurbishment | £255K | 6 Jul 2023 |
| University of Sheffield | 3726.EFM.SW.23 2023 Teaching and Learning Space Refurbishment | £581K | 10 May 2023 |
| University of Sheffield | 3513.EFM.SW.22 1&5 Northumberland Rd Refurbishment | £500K | 17 Nov 2022 |
Showing the 10 most recent of 30.
Where Assix Limited is registered
The registered office is in Sheffield (S9), in the Sheffield local authority area, England. Show S9 5AA on a map.
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- Rka Building Construction LtdFinishing trades
- The Driveway Company Sheffield LtdLandscapers and gardeners
- Abiza & Co Private LimitedBuilders
What happens if Assix Limited files late
Companies House charges an automatic penalty the day after the deadline, and it rises the longer the accounts are late. These are the dates for this company's accounts due on 31 March 2027.
| Companies House | Accounts delivered | Penalty |
|---|---|---|
| Up to 1 month late | 1 Apr 2027 to 30 Apr 2027 | £150 |
| 1 to 3 months late | 1 May 2027 to 30 Jun 2027 | £375 |
| 3 to 6 months late | 1 Jul 2027 to 30 Sep 2027 | £750 |
| More than 6 months late | From 1 Oct 2027 | £1,500 |
Penalties double if the accounts were also late the year before.
| HMRC (CT600) | From | Penalty |
|---|---|---|
| 1 day late | 1 Jul 2027 | £200 |
| 3 months late | 30 Sep 2027 | another £200 |
| 6 months late | 30 Dec 2027 | HMRC estimates the tax and adds 10% of the unpaid tax |
| 12 months late | 30 Jun 2028 | another 10% of any unpaid tax |
For returns filed on or after 1 April 2026. Late three times in a row and the £200 penalties become £1,000 each.
Company details
As held on the Companies House register.
- Company number
- 10512350
- Status
- Active
- Company type
- Private limited company
- Incorporated
- 6 December 2016 (9 years ago)
- Registered office
- F6 & F7 Epic House F6 & F7 Epic House, 18 Darnall Road, Sheffield, S9 5AA
- Nature of business
- Construction of commercial buildings (SIC 41201)
- Year end
- 30 June (accounting reference date)
- Accounts type
- Total exemption (full)
- Last accounts made up to
- 30 June 2025
- Last confirmation statement
- 2 December 2025
Filing notes for building contractors
Building companies often run the Construction Industry Scheme as a contractor, a subcontractor or both. CIS deductions suffered during the year are set against the PAYE bill, and any unrecovered balance at the year end matters when the accounts are drawn up.
Similar companies in Sheffield
Other active building contractors registered in Sheffield.
- B2L Construction & Landscaping Ltd2026
- Baiboon Group Ltd2013
- Bamforth Construction Ltd2015
- Barrow Construction Ltd2026
- Basement Dreams Ltd2025
- BDD Developments Limited2012
- Beaver Homes Limited2014
- Bee & Dee Builders Limited2003
All building contractors in Sheffield · All trades in Sheffield · Builders across the UK
Frequently asked questions
When are Assix Limited's accounts due?
Assix Limited's next accounts are due at Companies House by 31 March 2027 (in 170 days), covering the period to 30 June 2026.
When is Assix Limited's CT600 due?
The CT600 for the period to 30 June 2026 is due at HMRC by 30 June 2027, 12 months after the period end. The corporation tax itself is payable earlier, by 1 April 2027.
Is Assix Limited still trading?
Assix Limited is listed as active on the Companies House register as of 1 Oct 2026. Active means it has not been dissolved or entered insolvency; it does not show whether it is currently taking on work.
What does Assix Limited do?
Assix Limited is registered under Construction of commercial buildings (SIC 41201).
How old is Assix Limited?
Assix Limited was incorporated on 6 December 2016, 9 years ago.
Has Assix Limited won public sector contracts?
Yes. Assix Limited has 30 contract awards from public bodies on Contracts Finder and Find a Tender (those with their own published value total £14M), most recently from UNIVERSITY OF SHEFFIELD.
What is the penalty if Assix Limited files its accounts late?
Companies House charges £150 if the accounts are up to 1 month late, £375 up to 3 months, £750 up to 6 months and £1,500 after that, doubled if the previous year's accounts were also late. HMRC charges £200 for a CT600 filed a day late and another £200 at 3 months.
Official records
View Assix Limited on Companies House for filed documents, officers and the full history.
Based on the Companies House register (snapshot 1 Oct 2026). Deadlines are worked out from the register and assume a standard accounting period; a change of year end or a short period moves them. This page is general information, not tax or accountancy advice.