Re-sheeting vs Over cladding
In general, there are two principal categories of building envelope refurbishment: re-sheeting and over cladding.
Re-sheeting requires the existing building envelope to be completely removed and replaced by a new envelope system, whereas with over cladding, the existing building envelope is left in place and is used as a base layer for the installation of the new cladding system.
The choice between the two options will depend on the individual project requirements and circumstances. To assist in this decision, some of the key items for consideration of both systems are listed below: (visual taken from our latest Refurbishment technical paper).
Text only version of the key items for consideration of both re-sheeting and over cladding systems:
Advantages of re-sheeting:
- Potentially hazardous existing materials can be completely removed.
- The internal appearance of the building can be improved.
- There is potential to improve the internal working environment for occupants.
- It is easy to alter lighting configurations to optimum levels i.e. change pattern of windows and rooflights.
- Air-tightness and thermal performance levels similar to new buildings can be achieved.
- The existing structure is nearly always suitable for re-sheeting applications.
- There is an opportunity to alter the building configuration.
Disadvantages of re-sheeting:
- The cost of disposal of hazardous waste should be accounted for.
- The need for internal protection should be accounted for during the installation phase.
- Additional cost will be involved in re-sheeting.
- A higher level of disturbance to occupants and operational processes.
Advantages of over cladding:
- It is usually less expensive to over clad.
- On site installation is fast.
- There is minimal disturbance to building occupants.
- Insulation can be easily upgraded.
- Air-tightness levels similar to a re-sheet or new build can be achieved if considered at design stage.
- There is a reduced need for internal protection during installation.
Disadvantages of over cladding:
- Upgrading of internal appearance and lighting configurations is difficult.
- Over cladding relies on the integrity of the existing structure.