- Companies
- Specialist contractors
- London
- Open Building Systems Ltd
Open Building Systems Ltd
- Company number
- 04420926
- Incorporated
- 19 Apr 200224 years trading
- Registered office
- 167-169 Great Portland Street, Fifth Floor, London, W1W 5PF
- Nature of business
- Other specialised construction activities n.e.c.
Open Building Systems Ltd is a 24-year-old private limited company registered in London, company number 04420926, one of 4,318 specialist construction companies in London. Its next accounts are due at Companies House on 31 December 2027, and the CT600 for the period to 31 March 2027 is due at HMRC on 31 March 2028.
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 down £14K (-6.8%) on the year before, to £194K.
- Net assets rose in 5 of 8 year-on-year comparisons on record.
- Current assets of £270K against £86K owed within a year: 3.1 times cover.
- 6 employees on average during the year.
- Balance sheets on record for 10 years, 2017 to 2026.
Net assets by year
| Year end | Net assets | Cash | Current assets | Owed within a year | Employees |
|---|---|---|---|---|---|
| 31 Mar 2026 | £194K | £203K | £270K | £86K | 6 |
| 31 Mar 2025 | £208K | £106K | £398K | £200K | 6 |
| 31 Mar 2024 | £236K | £85K | £583K | £360K | 6 |
| 31 Mar 2023 | £143K | £114K | £341K | £207K | 4 |
| 31 Mar 2022 | £103K | £126K | £217K | £124K | 4 |
| 31 Mar 2021 | £84K | £139K | £184K | £106K | 4 |
| 31 Mar 2020 | £89K | £111K | £224K | £142K | |
| 31 Mar 2019 | £71K | £109K | £201K | £137K | |
| 31 Mar 2018 | £63K | £118K | £191K | £133K | |
| 31 Mar 2017 | £69K |
Where Open Building Systems Ltd is registered
The registered office is in London (W1W), in the Westminster local authority area, London. Show W1W 5PF on a map.
Other trade companies in W1W
- Civaris LtdSpecialist contractors
- R&R Construction Group LtdBuilders
- Aurum Cooling LtdPlumbers and heating engineers
- Steam Wood Stone LtdFinishing trades
- Hau Developments LimitedProperty developers
- Group Atlas Financial 83 LtdPainters and decorators
- Energy Reward LtdMotor traders
- Holly’S Housekeeping LtdCleaning companies
Shared registered office
1,494 companies on our pages use this registered office address. An address shared this widely is usually an accountant's office or a company formation agent's service address, not where the business trades from.
What happens if Open Building Systems Ltd 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 2027.
| Companies House | Accounts delivered | Penalty |
|---|---|---|
| Up to 1 month late | 1 Jan 2028 to 31 Jan 2028 | £150 |
| 1 to 3 months late | 1 Feb 2028 to 31 Mar 2028 | £375 |
| 3 to 6 months late | 1 Apr 2028 to 30 Jun 2028 | £750 |
| More than 6 months late | From 1 Jul 2028 | £1,500 |
Penalties double if the accounts were also late the year before.
| HMRC (CT600) | From | Penalty |
|---|---|---|
| 1 day late | 1 Apr 2028 | £200 |
| 3 months late | 30 Jun 2028 | another £200 |
| 6 months late | 30 Sep 2028 | HMRC estimates the tax and adds 10% of the unpaid tax |
| 12 months late | 31 Mar 2029 | 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
- 04420926
- Status
- Active
- Company type
- Private limited company
- Incorporated
- 19 April 2002 (24 years ago)
- Registered office
- 167-169 Great Portland Street, Fifth Floor, London, W1W 5PF
- Nature of business
- Other specialised construction activities n.e.c. (SIC 43999)
- Year end
- 31 March (accounting reference date)
- Accounts type
- Total exemption (full)
- Last accounts made up to
- 31 March 2026
- Last confirmation statement
- 16 March 2026
Filing notes for specialist construction companies
Specialist contractors often work under CIS for main contractors. Retentions held back by the customer still count towards turnover once the work is done.
Similar companies in London
Other active specialist construction companies registered in London.
- Oppong Company Limited2020
- Opr Construction Ltd2020
- Oprea Build Ltd2019
- Optic Software Ltd2025
- Optimal Parking Solutions Limited2017
- Options Joinery Ltd2020
- Optus HVAC Limited2021
- Opulure Ltd2024
All specialist construction companies in London · All trades in London · Specialist contractors across the UK
Frequently asked questions
When are Open Building Systems Ltd's accounts due?
Open Building Systems Ltd's next accounts are due at Companies House by 31 December 2027 (in 445 days), covering the period to 31 March 2027.
When is Open Building Systems Ltd's CT600 due?
The CT600 for the period to 31 March 2027 is due at HMRC by 31 March 2028, 12 months after the period end. The corporation tax itself is payable earlier, by 1 January 2028.
Is Open Building Systems Ltd still trading?
Open Building Systems Ltd 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 Open Building Systems Ltd do?
Open Building Systems Ltd is registered under Other specialised construction activities n.e.c. (SIC 43999).
How old is Open Building Systems Ltd?
Open Building Systems Ltd was incorporated on 19 April 2002, 24 years ago.
What is the penalty if Open Building Systems Ltd 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 Open Building Systems Ltd 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.