All floors should be considered to be in the dry zone in order to maintain durability. A life span in excess of 150 years should be achievable without any maintenance. In the case of extreme exposure conditions we can recommend further measures.
Damp Proof Course ‘dpc’
The beams at ground floor should sit on a dpc. A damp proof membrane is not required within the floor construction (the dpc and ventilated plenium will provide adequate moisture resistance).
In order to achieve an airtight floor a membrane can be incorporated into the floor above the insulation. Care should be taken to ensure overlaps taping and jointing details are carried out in accordance with good practice.
If Methane or Radon are present on site special membranes are required. Extreme care should be taken to ensure appropriate specification, design and detailing installation and protection of these membranes during construction.
In order that membranes perform at their best it is important not to trap built up gasses. These should be vented away via cross floor ventilation of the plenium and open perps in intermediate walls and peep weeps in the cavity walls.
MEMBRANES MUST NOT BE PUNCTURED
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