Design Guidance - Fasteners For Single Ply Roofs

Design Guidance

Specialist advice and design guidance on all matters relating to Icopal Tubular Washers, Pressure Plates and Screw Fasteners is freely available from our Technical Department.

 

  • General Design Guidance

    Insulation Attachment

    Icopal Thermazone PIR insulation boards should be attached at the minimum rate of 11 tubes & fasteners per 1.2 m x 2.4 m board (unless otherwise specified and approved). An increased density may be recommended depending on project location, height and exposure etc.

    Membrane Attachment

    For every mechanically fastened roof, a wind uplift calculation and fastener specification will be required prior to installation of the Icopal roof waterproofing membrane. All calculations are conducted in accordance with BS 6399 or BS EN 1991 parts 1-4, as appropriate.

    Fastener Application

    No pre-drilling is necessary for timber and steel decks.
    Simply insert the fastener through the tubular washer and install with a standard clutch drive electric screw gun (0 – 2500 rpm). Optimum fastener performance is achieved when fastener is installed perpendicular to the deck and into the top flutes of a steel deck.

    The TX-25 recess provides excellent drivability and the drill-point design cuts a hole in the steel deck maintaining contact between the deck and the minor diameter of the fastener, increasing back-out resistance.

    Quality Assurance

    Icopal Tubular Washers, Pressure Plates and Screw Fasteners are supplied under a Quality Management System approved to ISO 9001: 2004 by Swiss Association for Quality and Management Systems.

    Technical Services

    Specialist advice and design guidance on all matters relating to Icopal Tubular Washers, Pressure Plates and Screw Fasteners is freely available from our Technical Department

  • Selecting The Correct Tube Washer

    Guidance Notes (examples only)

    To optimize the benefits of the Icopal Tubular Washer system, ideally use the maximum length of tube washer and the minimum fastener length available.

    In certain applications, such as over-roofing of existing membrane and insulation layers, different tube lengths may be required.

    The tube washer should be chosen first; then the fastener can be selected.

    To select the maximum tube length (C) :

    i) deduct minimum 15 mm from the total build-up of the roof insulation (A) to allow for compression of the insulation (B).

    ii) choose the tube washer of that length or shorter. 

    eg, For an insulation buildup of 140 mm, the maximum tube length would be 125 mm, and so a 105 mm long Tube Washer would be chosen.

    Icopal-Screw-Fasteners-Guidance-Notes-01 

    Total roof system build-up (A) 140mm  
    Deduct compression tolerance (B)  -105mm  
    Maximum tube length  125mm  
    Chosen tube length (C) 105mm  
     

    Key:

    A: Total roof build-up depth

    B: Insulation compression tolerance (min 15mm)

    C: Tube Washer length

    D: minimum deck penetration or embedment

    E: min 20mm allowance for fastener in tube

    F: Fastener length

  • Selecting The Correct Fastener Length

    Guidance Notes (examples only)

    When selecting the correct Icopal Screw Fastener length, allow for the recommended minimum deck penetration or embedment and take into consideration the total build-up of the roof system, including any pressure plate, membrane, separation layers insulation, vapour barriers, existing systems and structural deck.

    To select the optimum fastener length (F) for tube washer applications:

    i) take the total roof system build-up measurement (A) and deduct the selected tube length (C).

    ii) allow for deck penetration (D) and then add minimum 20 mm allowance for the fastener within the tube (E) .

    iii) select the fastener at this length or longer.  

     Icopal-Screw-Fasteners-Guidance-Notes-01

    eg, For a 140 mm build-up over 0.7mm steel deck using a 105mm tube the minimum fastener length would be 70 mm.

    Total roof system build-up (A) 140mm  
    Deduct selected tube length (C)  -105mm  
    Add min. deck penetration/embedment (D)  +15mm  
    Add allowance for fastener within tube (E)
    +20mm  
    Minimum fastener length (F) 70mm  

    Key:

    A: Total roof build-up depth

    B: Insulation compression tolerance (min 15mm)

    C: Tube Washer length

    D: minimum deck penetration or embedment

    E: min 20mm allowance for fastener in tube

    F: Fastener length

  • Washer/Fastener Combinations - Metal Deck Applications

    Guidance Notes (examples only)

    The following table is provided as a quick reference guide for calculating the required tube washer and fastener combination for a new warm roof direct to a metal deck.

    The thickness of structural deck used for the combination is indicated in the table below. The fastener length should be altered accordingly where the structural deck thickness or system build-up is different.

    Metal Deck Application

    Structural Deck: 0.7mm steel Example, 0.7mm metal deck
    Minimum Deck Penetration: 20 mm though underside
       
    Suitable Fasteners: Icopal BS-4.8mm Carbon Steel Fastener
      Icopal BS-S-4.8mm Stainless Steel Fastener
       
    Tube Washer Type: Icopal R45 Membrane Tube Washer
      Icopal R75 Insulation Tube Washer 

     

    Insulation
    Thickness
    (mm)
     
    Tube Washer
    Length (mm)
    BS-4.8mm
    Carbon Steel
    Fastener (mm)
    BS-S-4.8mm
    Stainless Steel
    Fastener (mm)
    60 35 60 60
    70 35 70 80
    80 65 50 60
    90 65 60 60
    100 85 60 60
    110 85 60 60
    120 105 50 60
    130 105 60 60
    140 105 70 80
    150 135 50 60
    160 135 60 60
    170 135 70 80
    180 165 50 60
    190 165 60 60
    200 185 50 60
    210 195 50 60
    220 195 60 60
    230 195 70 80
    240 225 50 60
    250 225 60 60
    260 225 70 80
  • Washer/Fastener Combinations - Plywood Deck Applications

    Guidance Notes (examples only)

    The following table is provided as a quick reference guide for calculating the required tube washer and fastener combination for a new warm roof direct to a plywood deck.

    The thickness of structural deck used for the combination is indicated in the table below. The fastener length should be altered accordingly where the structural deck thickness or system build-up is different.

    Plywood Deck Application

    Structural Deck: 18mm plywood Example, 18 mm plywood deck
    Minimum deck penetration: 12mm though underside
       
    Suitable Fasteners: Icopal BS-4.8mm Carbon Steel Fastener
      Icopal BS-S-4.8mm Stainless Steel Fastener
       
    Tube Washer Type: Icopal R45 Membrane Tube Washer
      Icopal R75 Insulation Tube Washer 

     

    Insulation
    Thickness
    (mm)
     
    Tube Washer
    Length (mm)
    BS-4.8mm
    Carbon Steel
    Fastener (mm)
    BS-S-4.8mm
    Stainless Steel
    Fastener (mm)
    60 35 70 80
    70 35 80 80
    80 65 60 60
    90 65 70 80
    100 85 60 60
    110 85 70 80
    120 105 60 60
    130 105 70 80
    140 105 80 80
    150 135 60 60
    160 135 70 80
    170 135 80 80
    180 165 60 60
    190 165 70 80
    200 185 60 60
    210 195 60 60
    220 195 70 80
    230 195 80 80
    240 225 60 60
    250 225 70 80
    260 225 80 80
  • Washer/Fastener Combinations - Concrete Deck Applications

    Guidance Notes (examples only)

    The following table is provided as a quick reference guide for calculating the required tube washer and fastener combination for a new warm roof direct to a concretel deck.

    The thickness of structural deck used for the combination is indicated in the table below. The fastener length should be altered accordingly where the structural deck thickness or system build-up is different.

    Concrete Deck Application

    Structural Deck: Concrete † example concrete deck
    Minimum deck embedment: 20 mm though underside
       
    Suitable Fasteners: Icopal TI-T25 6.3 mm Carbon Steel Fastener
      - Pilot hole diameter to be determined by a pull out test.
      - Drill depth to be 10 – 25 mm greater than fastener embedment, to allow for swarf.
       
    Tube Washer Type: Icopal R45 Membrane Tube Washer
      Icopal R75 Insulation Tube Washer 

    † Note: Fastener length & Tube Washer combination has been calculated based on fixing direct to concrete slab without screed. 

    Insulation
    Thickness
    (mm)
     
    Tube Washer
    Length (mm)
    Icopal TI-T25
    Carbon Steel
    Fastener (mm)
    60 35 60
    70 35 70
    80 65 50
    90 65 60
    100 85 60
    110 85 60
    120 105 50
    130 105 60
    140 105 70
    150 135 50
    160 135 60
    170 135 70
    180 165 50
    190 165 60
    200 185 50
    210 195 50
    220 195 60
    230 195 70
    240 225 50
    250 225 60
    260 225 70
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