Viewpoint: Top 10 things to consider when repairing or replacing a glazed roof

Development Services | David Hollingsworth | 24 March 2020

As a building owner, or even a tenant, when you have a glazed roof that has seen better days, it’s not just a matter of simply comparing the cost of repair and replacement.

We look at the top ten crucial factors that need to be considered:

  • that will decrease the risk of exposing your project to delays, overspend and potential claims of damage
  • the list of consultants you may need to instruct
  • and a recent case study showing the practicalities involved

1. Planning Law or Building Control: need Planning Permission or Building Regulations approval?

  • This will depend on your project’s complexity, but remaining compliant will help in reaching completion on time and in budget, and reduce potential issues when disposing of the property.

2. Love thy neighbour: Party Wall and neighbourly matters really matter

  • The Party Wall etc Act 1996 may trigger statutory obligations that you’ll need to fulfil.
  • Beyond the Act, all rights of way, rights for access for scaffolds and cranes, management of noise and movement, will all involve careful liaison with neighbouring owners and occupiers.
  • Land Registry searches will determine the owners of adjacent buildings, remembering that someone who is a tenant with a lease for more than a year is considered an “owner”.
  • A lease would usually include a demised plan showing the extent of your ownership.

3. Feasibility Study: to repair or replace?

  • Ultimately, it’s all down to money; what will best protect and enhance your asset and give you peace of mind in the future.
  • Compare upfront costs, ongoing repair and maintenance (both known and unknown), and ease of installation versus repair, whilst complying with current planning, Party Wall and H&S requirements.

4. Types of system

  • The most appropriate type of system will need to be based on a professional assessment of the existing structure. Building control will almost certainly need to know the outcome of this.
  • Consideration also needs to be given to other elements, eg, method of fixing, access, building (current thermal and acoustic performance) regulations, the implications of solar heat gain, minimising future repairs including terms of any guarantee or warranty.

5. Liaise with all the stakeholders

  • Talk to the end-user or tenant. Their view as to how the space is regularly used and their needs should be taken into account, as well as how to minimise disruption during the works.
  • Consider future plans for the building, such as sub-divisions.

6. Design and tender

  • A detailed specification should be prepared for tender. You should consider the:
      • type of contractor
      • type of contract to be used
      • budget

7. Installation

  • The size of the roof being replaced or repaired will dictate the length of time works will take, also accounting for the design process of any new installation.
  • You’ll need to protect the building, whilst causing the least amount of business interruption.

8. Health & Safety: CDM regulations

  • Works will fall under Construction (Design and Management) Regulations 2015, which applies to all demolition, construction and maintenance works.
  • You need to know your obligations. Failing to comply is serious and incurs criminal liability.

9. Schedule of Condition: protecting both Landlord and Tenant

  • Commission a professional Schedule of Condition before the work commences.
  • As a landlord, you’ll need to protect yourself against any allegation of damage, ie, no claim if the alleged defect is recorded within the schedule prior to the works commencing.
  • As a tenant, you should be looking to reduce your repairing liability under the lease (on the basis that these roofing works are on behalf of the landlord).

10. Insurance

  • Consider the amount of:
      • public liability insurance
      • professional indemnity insurance
      • contractor insurance (is it “all risks”)

What consultants might you need to appoint?

  • Project Manager/Contract Administrator
  • Planning Consultant
  • Party Wall Surveyor
  • Structural Surveyor
  • Services Consultant
  • Mechanical and Electrical Engineers
  • Principal Designer



Before, during and after the works


Our client came to us with concerns over a failing glazed roof system, causing water ingress into a high specification office space.

  • Investigation revealed this was caused by poor detailing around the opening sections of the glazed roof.
  • Our feasibility study revealed that to carry out any works in a safe manner would involve the installation of a crash deck beneath the roof, which in turn was positioned over a fully glazed staircase, in a fully occupied office.
  • Coupled with the benefits that a new system would provide, a replacement roof was deemed the best course of action in this instance.

A technically complex project, we undertook the following activities:

  • Liaison with the Local Authority as the building was in a Conservation Area.
  • Close co-operation with neighbours to facilitate agreement concerning the erection of scaffolding on their land. By undertaking repairs to their building we mitigated the high costs of a scaffold licence.
  • Project managed a range of separately appointed consultants, including structural engineers, mechanical and electrical engineers and approved inspectors, which included:
      • assessments to determine if the proposed removal of the existing glazed roof opening vents would have an impact on the heating and cooling of the office space
      • specialist design input to ensure that the glazed roof reduced solar glare and improved heat loss
  • The role of Principal Designer to ensure Health and Safety was closely controlled.
  • Liaison with the tenant to ensure security and access was maintained throughout the works period.
  • Oversaw that the installation took place in a safe manner.

Benefits to the client:

  • The existing tenant was able to stay within the building during the works.
  • Future energy savings following an improved insulated glazing system.
  • The new roof is guaranteed from future failure for a number of years.

Matt Kelly, Anglezark, owner of the property said:
“Powell Williams executed this complex project seamlessly and with great precision, managing a large number of stakeholders and consultants in the process. I’m delighted with the result, as is the tenant. It’s all about trusting someone to provide exactly the service I expect, and Powell Williams always delivers.”


Any questions? Do contact Philip Ives, who will be pleased to help you.



David Hollingsworth

David Hollingsworth

+44 (0) 7432 315 476

Share this news