- Company number
- 10912999
- Incorporated
- 14 Aug 20179 years trading
- Registered office
- Balby Court Business Campus, Balby Carr Bank, Doncaster, DN4 8DE
- Nature of business
- Construction of commercial buildings
Castle Steel Buildings Limited is a 9-year-old private limited company registered in Doncaster, company number 10912999, one of 306 building contractors in Doncaster. Its next accounts are due at Companies House on 31 May 2027, and the CT600 for the period to 31 August 2026 is due at HMRC on 31 August 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 £10K (+20.6%) on the year before, to -£40K.
- Net assets rose in 3 of 7 year-on-year comparisons on record.
- Current assets of £33K against £73K owed within a year: 0.5 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 Aug 2025 | -£40K | £2,100 | £33K | £73K | 2 |
| 31 Aug 2024 | -£50K | £6,765 | £17K | £58K | 2 |
| 31 Aug 2023 | £3 | £16K | £53K | £24K | 4 |
| 31 Aug 2022 | £7 | £12K | £47K | £47K | 3 |
| 31 Aug 2021 | £2 | £59K | £96K | £97K | 2 |
| 31 Aug 2020 | £2 | £6,762 | £14K | £15K | 2 |
| 31 Aug 2019 | -£3,319 | £50 | £6,770 | £20K | |
| 31 Aug 2018 | £2,655 | £9,256 | £31K | £40K |
Where Castle Steel Buildings Limited is registered
The registered office is in Doncaster (DN4), in the Doncaster local authority area, Yorkshire and The Humber. Show DN4 8DE on a map.
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- Brookes Home and Heating LtdBuilders
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- Team Clean Group Commercial LtdCleaning companies
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Also registered at this address
3 other companies use the same registered office as Castle Steel Buildings Limited.
- 1ST Ground Construction Management Services LtdProperty developers
- All Trade Systems LtdProperty developers
- Conform Safety Management LtdSpecialist contractors
What happens if Castle Steel Buildings 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 May 2027.
| Companies House | Accounts delivered | Penalty |
|---|---|---|
| Up to 1 month late | 1 Jun 2027 to 30 Jun 2027 | £150 |
| 1 to 3 months late | 1 Jul 2027 to 31 Aug 2027 | £375 |
| 3 to 6 months late | 1 Sep 2027 to 30 Nov 2027 | £750 |
| More than 6 months late | From 1 Dec 2027 | £1,500 |
Penalties double if the accounts were also late the year before.
| HMRC (CT600) | From | Penalty |
|---|---|---|
| 1 day late | 1 Sep 2027 | £200 |
| 3 months late | 30 Nov 2027 | another £200 |
| 6 months late | 29 Feb 2028 | HMRC estimates the tax and adds 10% of the unpaid tax |
| 12 months late | 31 Aug 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
- 10912999
- Status
- Active
- Company type
- Private limited company
- Incorporated
- 14 August 2017 (9 years ago)
- Registered office
- Balby Court Business Campus, Balby Carr Bank, Doncaster, DN4 8DE
- Nature of business
- Construction of commercial buildings (SIC 41201)
- Year end
- 31 August (accounting reference date)
- Accounts type
- Total exemption (full)
- Last accounts made up to
- 31 August 2025
- Last confirmation statement
- 16 August 2026
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 Doncaster
Other active building contractors registered in Doncaster.
- Ceiling Stands Ltd2024
- CGS (Yorkshire) Ltd2013
- Che Group Limited2025
- Cheswold Homes Limited2021
- Church Street Bawtry Limited2022
- Ckinfrastructure Ltd2026
- Claylane Brickwork Limited2022
- Claylane Construction Ltd2007
All building contractors in Doncaster · All trades in Doncaster · Builders across the UK
Frequently asked questions
When are Castle Steel Buildings Limited's accounts due?
Castle Steel Buildings Limited's next accounts are due at Companies House by 31 May 2027 (in 230 days), covering the period to 31 August 2026.
When is Castle Steel Buildings Limited's CT600 due?
The CT600 for the period to 31 August 2026 is due at HMRC by 31 August 2027, 12 months after the period end. The corporation tax itself is payable earlier, by 1 June 2027.
Is Castle Steel Buildings Limited still trading?
Castle Steel Buildings 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 Castle Steel Buildings Limited do?
Castle Steel Buildings Limited is registered under Construction of commercial buildings (SIC 41201).
How old is Castle Steel Buildings Limited?
Castle Steel Buildings Limited was incorporated on 14 August 2017, 9 years ago.
What is the penalty if Castle Steel Buildings 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 Castle Steel Buildings 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.