Service Penetrations in Framing Building Codes & Rules
- Service Penetrations in Framing Tools™ simplifies the National Construction Code (NCC) with interactive graphics, including deemed to comply & best practices.
Manufacturer's Requirement
Hole Spacing
Refer to Hotspot
Flange
Floor
No holes allowed
D
Edge
Edge
Steel
Studwork
AS 1684.2:2021, 6.2.1.4
Drill HolesAS 1684.2:2021, 6.2.1.4
- ≤ Ø 25 within middle half of timber bottom plate
AS 1684.2:2021, 6.2.1.4
Drill HolesAS 1684.2:2021, 6.2.1.4
- ≤ Ø 25 within middle half of timber stud
B
D
Stud Depth
Timber
Studwork
Web
Framing Overview (Light Steel)
Drilling Timber Bearers & Joists
- These rules keep the structure strong and safe[1][2]
- Imperfections like knots in the wood should be treated as holes when considering spacing
- Check special rules for engineered timber
Timber Floor Framing Hole RULES
NCC 2022 V2
All Building Classes
NCC 2022 H1V1, H1D6, 6.1.1
[2019 V2.1.1, 3.4.0, 3.4.2-3.4.4]
May 2023
NCC 2022 Vol 2, H1D6 (4) (c)
AS 1684.2:2021, 4.1.6
- Framing members to be structurally resilient to NCCNCC 2022 Vol 2, H1D6 (4) (c)
- Cuts, holes, & notches must follow specific size & spacing rulesAS 1684.2:2021, 4.1.6
- Vertical holes
- Max Ø Hole = B ÷ 4
- Drilled through centreline
- Min Spacing = B x 6
- Horizontal holes
- Spacing & max Ø varies dependant on D
- Spacing & size as per details
AS 1684.2:2021, 4.1.6
AS 1720.1:2010, 4.1.6
- These rules keep the structure strong and safeAS 1684.2:2021, 4.1.6AS 1720.1:2010, 4.1.6
- Imperfections like knots in the wood should be treated as holes when considering spacing
- Check special rules for engineered timber
Wall Studs & Plates Notching (Timber)
Clearance
from
Flanges
Hole Spacing
Hole Spacing
W
Ø
Refer Manufacturers' requirements
AS 1684.2:2021, 4.1.6
≥ B X 6AS 1684.2:2021, 4.1.6
Industry Recommendation
NCC 2022 HP, 6.3.8
Steel StudsIndustry Recommendation
- Predrilled by manufacturer
- Get advice prior to drilling on site
- Penetrations as per NCC requirementsNCC 2022 HP, 6.3.8
Informative
Install BushingsInformative
- To protect cable sheathing
- Sound isolation to plumbing
Manufacturer's Requirement
AS 1684.2:2021, 6.2.1.4
≥ D X 3AS 1684.2:2021, 6.2.1.4
Manufacturer's Requirement
AS/NZS 3000:2018, 5.4.6
EarthingAS/NZS 3000:2018, 5.4.6
- Structural Framing must be Earthed if Building is connected to an Electrical Installation
Floor Framing (Timber)
Framing Overview (Timber)
I Joist
- Width & diameter hole size by Manufacturer's Requirements[1]
- Drill through centerline
- ≥ 300mm, or 2W, or 2Ø Spacing between holes
- ≥ 5mm Clearance from flanges
Timber I-Joist Penetrations Requirements
NCC 2022 V2
Manufacturer's Requirement
- Full compliance to Manufacturer's Requirement ensures structural safety & longevity of the timberManufacturer's Requirement
- Holes should be drilled without overcutting
- ≤ 3 holes per span if the width or diameter of the hole is ≥ 75mm
- No requirements on how many holes you can drill on a span if the width or diameter of the hole is Ø ≤ 40mm as long as they are spaced by the minimum recommended
- Any hole, no matter the size, should be spaced from each other ≥ 300mm, or double the width, or diameter of the larger hole (2W, or 2Ø)
- ≥ 5mm clearance from flanges to protect glue bond
- Round holes may be grouped together, provided they meet the requirements for an equivalent larger hole
Manufacturer's Requirement
- Width & diameter hole size by Manufacturer's RequirementsManufacturer's Requirement
- Drill through centerline
- ≥ 300mm, or 2W, or 2Ø Spacing between holes
- ≥ 5mm Clearance from flanges
Wall Framing (Timber)
Redirecting... (5)