Deck25 Grooved & Woodgrain

    Joist spacing

Deck25 Grooved & Woodgrain

 All Deck25 Composite, Softwood and Hardwood Decks require good Airflow through the substructure ie: Air must flow freely around The timber components that make up the supporting frame.

Good Airflow will protect your deck and maximise it's operational life

Standard Raised Deck. Airflow is achieved through the sides of the deck. Should the perimeter be closed in ( fully skirted ) It is important to install 100mm - 150mm air vents on opposite sides of the deck, contained within the skirt. The General  rule for a closed in Deck is to install 2no. air vents for every 12m2 of Deck surface area

Sunken and enclosed Decks

These are situations where air vents cannot be installed in the sides. 

This is achieved by installing air vents in the surface of the perimeter deck boards. Rectangular strip vents or circular air vents of 80mm - 100mm diameter should be installed on opposite sides. The general rule applies: Install 2no. air vents for every 10m2 of deck surface area. Air vents chosen should be made from plastic, Stainless steel or GRP.

 please note:

Where airflow is further restricted eg High wall around deck or solid panel safety barrier  system ( glass, steel or polycarbonate), this will also inhibit airflow.  It is good practice to increase gapping between deck boards from 5mm to 7mm to assist evaporation of water from the deck frame cavity. This is particularly important when decking over a flat or near flat roof.

Ensure that the supporting Deck Frame is elevated above the roof membrane using rubber packers, rubber blocks or rubber shoes.

Minimum clearance between the bottom of the timber joist (frame) and the roof membrane /surface should be 25mm. The more the better.