During the construction stage the following should be complied with to minimise air leakage:
Site management and supervision are vital to ensure correct quality control procedures are followed.
Regular inspections should be carried out to ensure the detailed airtightness provisions are being implemented.
Where ACDs are being used, the supplied checklists for these ACDs should be followed strictly.
The sequence of construction works must be examined to ensure that the air barrier is complete before any follow-on trades can commence.
Site operatives should be clearly instructed on items of the site barrier and shown the difference between it and vapour control layers, etc.
All proprietary materials used in the air barrier must have the correct certification and approval.
The manufacturer should be consulted if there is any doubt regarding the air barrier installation.
Follow-on trades must be warned not to damage the air barrier and inspections will take place before wall closures go ahead.
If additional service opes are required, the air barrier should be effectively sealed around these additions and any damage repaired.
The air permeability pressure test must return at least the minimum results required to gain compliance with the building regulations.
All air permeability tests must be retained by the developer and copies should be submitted to the owner.
Copies of the air permeability test results should be given to the designer, who can check the results against the desired results calculated at the design stage.
The quality control system should be prepared for the eventuality of damage or failure and should have repair measures in place to use if they are required.
The largest number of air leakage points typically comes from the penetration of services. Not unusually, these leaks are unnoticed due to their positioning (e.g. behind kitchen units, bath panels, etc.) Sufficient space is required around each service to fully ensure that the ope can be sealed. Where numerous services are entering in close proximity, they must be adequately spaced to allow a good seal to be formed around each service.
