- Companies
- Joiners and carpenters
- London
- Sash Window Insulation Limited
Sash Window Insulation Limited
- Company number
- 15839258
- Incorporated
- 15 Jul 20242 years trading
- Registered office
- 128 City Road, London, EC1V 2NX
- Nature of business
- Joinery installation; Glazing; Other telecommunications activities; Other business support service activities n.e.c.
Sash Window Insulation Limited is a 2-year-old private limited company registered in London, company number 15839258, one of 692 joinery companies in London. Its next accounts are due at Companies House on 30 April 2027, and the CT600 for the period to 31 July 2026 is due at HMRC on 31 July 2027.
Key dates
Worked out from the year end and filing history on the Companies House register.
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Financial snapshot, 2025
From the balance sheet at 31 July 2025, as filed at Companies House.
Where Sash Window Insulation Limited is registered
The registered office is in London (EC1V), in the Islington local authority area, London. Show EC1V 2NX on a map.
Other trade companies in EC1V
- Cardiff Electrical Solutions LtdElectricians
- Edemis Construction LtdBuilders
- Zaylan LtdProperty developers
- Pronto Roofing and Construction LtdRoofers
- Instal Systems LtdPlumbers and heating engineers
- J&R Partners LtdBuilders
- The Tile Craft LtdFinishing trades
- Cathal Od Solutions LtdSpecialist contractors
Shared registered office
2,436 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 Sash Window Insulation 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 30 April 2027.
| Companies House | Accounts delivered | Penalty |
|---|---|---|
| Up to 1 month late | 1 May 2027 to 31 May 2027 | £150 |
| 1 to 3 months late | 1 Jun 2027 to 31 Jul 2027 | £375 |
| 3 to 6 months late | 1 Aug 2027 to 31 Oct 2027 | £750 |
| More than 6 months late | From 1 Nov 2027 | £1,500 |
Penalties double if the accounts were also late the year before.
| HMRC (CT600) | From | Penalty |
|---|---|---|
| 1 day late | 1 Aug 2027 | £200 |
| 3 months late | 31 Oct 2027 | another £200 |
| 6 months late | 31 Jan 2028 | HMRC estimates the tax and adds 10% of the unpaid tax |
| 12 months late | 31 Jul 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
- 15839258
- Status
- Active
- Company type
- Private limited company
- Incorporated
- 15 July 2024 (2 years ago)
- Registered office
- 128 City Road, London, EC1V 2NX
- Nature of business
- Joinery installation (SIC 43320)
Glazing (SIC 43342)
Other telecommunications activities (SIC 61900)
Other business support service activities n.e.c. (SIC 82990) - Year end
- 31 July (accounting reference date)
- Accounts type
- Micro-entity
- Last accounts made up to
- 31 July 2025
- Last confirmation statement
- 14 July 2026
Filing notes for joinery companies
Joinery companies can carry stock and work in progress at the year end, especially bespoke workshop work, and that figure moves the profit for the year.
Similar companies in London
Other active joinery companies registered in London.
- Saw&Co Limited2015
- SC Fitting Ltd2015
- Schotten & Hansen UK Ltd.2019
- SCL Carpentry Limited2011
- SD Prime Windows & Doors Ltd2026
- Sean McGoey Fittings Limited2005
- Seb Carpentry & Joinery Ltd2014
- Seclorum Limited2003
All joinery companies in London · All trades in London · Joiners and carpenters across the UK
Frequently asked questions
When are Sash Window Insulation Limited's accounts due?
Sash Window Insulation Limited's next accounts are due at Companies House by 30 April 2027 (in 200 days), covering the period to 31 July 2026.
When is Sash Window Insulation Limited's CT600 due?
The CT600 for the period to 31 July 2026 is due at HMRC by 31 July 2027, 12 months after the period end. The corporation tax itself is payable earlier, by 1 May 2027.
Is Sash Window Insulation Limited still trading?
Sash Window Insulation 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 Sash Window Insulation Limited do?
Sash Window Insulation Limited is registered under Joinery installation (SIC 43320); Glazing (SIC 43342); Other telecommunications activities (SIC 61900); Other business support service activities n.e.c. (SIC 82990).
How old is Sash Window Insulation Limited?
Sash Window Insulation Limited was incorporated on 15 July 2024, 2 years ago.
What is the penalty if Sash Window Insulation 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 Sash Window Insulation 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.