The floor joists of the floor requiring upgrading must be equal or larger in size than the ones that were submitted to the Standard Fire Test for the Foamed Vermitex 'AF' system. Special attention is required for all types of penetrations through Timber Floor systems. In some cases these Services penetrations, should be totally isolated with proven non-combustible mortars to the immediate vicinity of the Fire collars. Approval has been granted for the installation of Fire Collars within the ‘Foamed Vermitex’ system to cater for existing and new Services risers.
With Heritage Ceilings and especially when installing ‘Foamed Vermitex’ full floor examinations and careful planning are recommended. Please refer to LAF for further details.
After the application of ‘Foamed Vermitex’ natural ventilation should be allowed (forced ventilation will expedite the process). In naturally ventilated conditions sufficient ‘drying time’ (3-6 weeks (1)) should always be allowed before the Floor boards are replaced. This is to prevent moisture being entrapped within the voids thus resulting in excessive moisture absorption by the Ceiling.
When installing ‘Foamed Vermitex’ we always recommend that a water-resistant sealant be applied (1) above the ceiling to prevent undue moisture absorption.
NOTE (1): If this is not carried out efflorescence or mould may appear to the underside of stable Ceilings and in the case of old and dilapidated ceilings this may have grave consequences, with the collapse of the Ceiling membrane a distinct possibility!
With such ceilings, we do recommend ‘stabilisation’ and in particular cases ‘full restoration’, before proceeding with the application of ‘Foamed Vermitex’ (please refer to Heritage Council of NSW or L & A Fazzini MFG P/L for information).