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How to accommodate penetrations in decks

24 January 2017 No Comment

Penetrations through decks affect the structural integrity, and therefore must be suitably braced, dependant on opening size.

1 – Small penetrations, through the bottom trough, can be accommodated without any additional support. Multiple penetrations must be spaced at 1500 mm minimum centres.  Note: no part of the web, or crown, can be removed without additional support.

RoofDek Profile Trough Width Pitch
D32 27mm 200mm
D35 35mm 150mm
D46 67mm 225mm
D60 64mm 200mm
D100 63mm 233.3mm
D135 43mm 310mm
D159 38mm 250mm
D200 75mm 375mm


2 – Medium penetrations, up to one profile pitch, require a stiffening plate. The stiffening plate is generally installed above the deck, however for retro fitting of penetrations, where the roof build is installed, the stiffening plate can be installed, the stiffening plate can be installed under the deck.

Stiffening plate to be square, extending over the top flange of adjoining complete profiles.  D159 and deeper decks require a plate thickness of 3mm, all other decks to be 2mm. Stiffening plate requires fixing with Tec screws, or rivets, to fastener manufacturers recommendations.


3 – Larger penetrations, greater than one profile pitch, require full structural reinforcement – see RoofDek Installation Details for further information.



Dektite® closures

Penetrations can be sealed with Dektite® closures, suitable for small diameter cable penetrations or large pipework up to 440mm diameter.

Box penetrations up to 255mm square can also be accommodated. Larger square or rectangular penetrations may be sealed with Dekstrip® expandable-edge flashing.

Dektite® closures are available in Grey EPDM or Red Silicone to suit operating temperatures:-

  • EPDM will withstand constant temperatures at the roofline of -50°C to 115°C, and up to 150°C intermittently.
  • Red Silicone will withstand constant temperatures at the roofline of -50°C to 200°C, and up to 250°C intermittently.

Dektite® Images courtesy of Deks

For further information please do not hesitate to get in touch with our Technical Department at Tata Steel
E mail: technical.structuralproducts@tatasteel.com

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