Norwegian Foundation Depth & Width: Why TEK17 Sets No Fixed Number

The requirement

TEK17 sets no fixed footing depth, width, concrete grade or rebar cover. There is no frost-line rule and no metre figure in the code. §10-2(3) hands all of it to design under the Eurocode standards. Depth and width come from your site’s ground and loads, not from the regulation.

Foundation design sits under TEK17 Chapter 10, the structural safety chapter, at §10-2. That clause covers the basic requirements for a structure’s mechanical resistance and stability, including ground conditions. It routes them to the Eurocode series with the Norwegian National Annexes. That means NS-EN 1990 for the basis of design, plus NS-EN 1991 through NS-EN 1999. For footings and ground, the key one is NS-EN 1997, Eurocode 7. It covers the geotechnical design. No metre figure is printed in TEK17 or its official guidance, the veiledning.

A frost-depth figure sometimes gets quoted on site. It comes from SINTEF Byggforsk’s Byggforskserien. That series is respected trade guidance, but it is paywalled and it is not law. It is not part of TEK17. So no quoted number is safe to treat as a code minimum. Frost depth depends on your site and your region. TEK17 §10-2 defers it to the geotechnical design under Eurocode 7.

1. 1 footing
2. 2 ground

Width has no fixed table either. Some codes print a width table by soil type and load. TEK17 does not. Strip-footing width comes out of Eurocode 7 design. It rests on your soil’s bearing capacity against the building’s real loads. You work it out per project.

The concrete and the cover. The concrete grade is not in TEK17 either. That job goes to Eurocode 2, NS-EN 1992. It sets the strength class by exposure and by the structural design. Rebar cover follows the same route. It comes from the exposure-class cover tables in NS-EN 1992-1-1, not from one national figure.

Work out the concrete volume

Use the concrete sizes on the approved plan. Embedment is the depth from ground level to the base of the footing. It is not the thickness of concrete to pour. A strip, wall and trench fill each have their own shape. Work out each part on its own. Where parts meet, count that concrete once.

This example uses a straight concrete strip with the same size all along:

• Total concrete length: 24 m.
• Concrete width: 0.50 m.
• Concrete thickness, measured from its top to its underside: 1.0 m.

These are example sizes, not code limits or a footing design. Check the shape and size on the plans. Then check how deep the base must sit. It must meet the soil and frost rules for the site.

Volume = length × concrete width × concrete thickness.

24 × 0.50 × 1.0 = 12.0 m³.

That is the volume before any extra for waste or uneven ground. Measure the trench or forms. Agree the extra amount and final order with the supplier. The tool does the sum. It does not choose safe footing sizes.

Do it in 5 seconds

Related

• Part of the Norwegian Building Regulations hub. One national regulation, with the veiledning and calculators that solve it.
• Setting out the stairs on the same build? See Norwegian stair & guard rules.

Sources

• TEK17 §10-2 (Konstruksjonssikkerhet) — the deferral to the Eurocode design series for foundation depth, width, concrete grade and rebar cover. Read it at dibk.no.

Read this first. These figures reflect TEK17 as amended, in force since 1 July 2017. Foundation design in Norway runs through Eurocode 7 (NS-EN 1997) for ground/depth/width and Eurocode 2 (NS-EN 1992) for concrete and cover, with Norwegian National Annexes applying — this is TEK17’s own deliberate deferral, not a gap in research, and no single depth or width figure should be presented as a national minimum. Get your ground checked by a proper site investigation before you dig.