- Companies
- Plumbers and heating engineers
- Harlow
- STJ Mechanical Limited
STJ Mechanical Limited
- Company number
- 10785425
- Incorporated
- 23 May 20179 years trading
- Registered office
- 87 Westbury Rise, Harlow, CM17 9NT
- Nature of business
- Plumbing, heat and air-conditioning installation
STJ Mechanical Limited is a 9-year-old private limited company registered in Harlow, company number 10785425, one of 97 plumbing and heating companies in Harlow. Its next accounts are due at Companies House on 31 December 2026, and the CT600 for the period to 31 March 2026 is due at HMRC on 31 March 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 £15K (+24.2%) on the year before, to £78K.
- Net assets rose in 7 of 7 year-on-year comparisons on record.
- Current assets of £89K against £23K owed within a year: 3.9 times cover.
- 2 employees on average during the year.
- Balance sheets on record for 8 years, 2018 to 2025.
Net assets by year
| Year end | Net assets | Cash | Current assets | Owed within a year | Employees |
|---|---|---|---|---|---|
| 31 Mar 2025 | £78K | £89K | £23K | 2 | |
| 31 Mar 2024 | £63K | £70K | £21K | 2 | |
| 31 Mar 2023 | £47K | £55K | £24K | 2 | |
| 31 Mar 2022 | £35K | £45K | £27K | 2 | |
| 31 Mar 2021 | £28K | £38K | £24K | 2 | |
| 31 Mar 2020 | £23K | £28K | £16K | 2 | |
| 31 Mar 2019 | £7,659 | £20K | £16K | 2 | |
| 31 Mar 2018 | £2,751 | £22K | £23K | 1 |
Where STJ Mechanical Limited is registered
The registered office is in Harlow (CM17), in the Harlow local authority area, East of England. Show CM17 9NT on a map.
Other trade companies in CM17
- Ella's Team Home Improvement LtdLandscapers and gardeners
- Page & Co Construction LimitedBuilders
- Woodside Contracting LimitedProperty developers
- RBPG Response LimitedInstallers
- Black Eagle Mobile Tyres LtdMotor traders
- Prime Roofing & Building LtdRoofers
- Clinto Properties LtdProperty developers
- Om Electrics LtdElectricians
What happens if STJ Mechanical 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 December 2026.
| Companies House | Accounts delivered | Penalty |
|---|---|---|
| Up to 1 month late | 1 Jan 2027 to 31 Jan 2027 | £150 |
| 1 to 3 months late | 1 Feb 2027 to 31 Mar 2027 | £375 |
| 3 to 6 months late | 1 Apr 2027 to 30 Jun 2027 | £750 |
| More than 6 months late | From 1 Jul 2027 | £1,500 |
Penalties double if the accounts were also late the year before.
| HMRC (CT600) | From | Penalty |
|---|---|---|
| 1 day late | 1 Apr 2027 | £200 |
| 3 months late | 30 Jun 2027 | another £200 |
| 6 months late | 30 Sep 2027 | HMRC estimates the tax and adds 10% of the unpaid tax |
| 12 months late | 31 Mar 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
- 10785425
- Status
- Active
- Company type
- Private limited company
- Incorporated
- 23 May 2017 (9 years ago)
- Registered office
- 87 Westbury Rise, Harlow, CM17 9NT
- Nature of business
- Plumbing, heat and air-conditioning installation (SIC 43220)
- Year end
- 31 March (accounting reference date)
- Accounts type
- Micro-entity
- Last accounts made up to
- 31 March 2025
- Last confirmation statement
- 3 March 2026
Filing notes for plumbing and heating companies
Plumbing and heating companies frequently work under CIS for main contractors and also directly for homeowners, so turnover can mix CIS and non-CIS income.
Similar companies in Harlow
Other active plumbing and heating companies registered in Harlow.
- T. Patton Limited1982
- The Boiler Installation Specialists Ltd2008
- Tidehill Limited2002
- TT Fires Ltd2010
- Twin Plumbing and Ventilation Limited2020
- A & E Central Heating Services Ltd2023
- A-Star Fire Sprinklers Ltd2022
- Abd Handyman Services Ltd2021
All plumbing and heating companies in Harlow · All trades in Harlow · Plumbers and heating engineers across the UK
Frequently asked questions
When are STJ Mechanical Limited's accounts due?
STJ Mechanical Limited's next accounts are due at Companies House by 31 December 2026 (in 79 days), covering the period to 31 March 2026.
When is STJ Mechanical Limited's CT600 due?
The CT600 for the period to 31 March 2026 is due at HMRC by 31 March 2027, 12 months after the period end. The corporation tax itself is payable earlier, by 1 January 2027.
Is STJ Mechanical Limited still trading?
STJ Mechanical 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 STJ Mechanical Limited do?
STJ Mechanical Limited is registered under Plumbing, heat and air-conditioning installation (SIC 43220).
How old is STJ Mechanical Limited?
STJ Mechanical Limited was incorporated on 23 May 2017, 9 years ago.
What is the penalty if STJ Mechanical 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 STJ Mechanical 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.