Indonesian Foundations: No Frost Rule, Design-Driven Depth

The requirement

Get the footing depth from the site design. The rule is Permen PU No. 29/PRT/M/2006, Bab III.3.1.d.i. It sets depth by your ground instead. The footing base must sit on soil that can carry the load. Your site’s soil check sets the depth you dig to.

Check climate and ground conditions for the actual site. A broad climate label is not a substitute for the ground report.

The rule comes from the Ministry of Public Works (Pedoman Persyaratan Teknis Bangunan Gedung). Bab III.3.1.d.i spells out the depth test. The footing base must reach a soil layer with enough stable bearing capacity. A ground and site investigation has to confirm that layer. The building must also not settle past its limits over its life. So dig to whatever depth your soil report calls for. Do not treat one depth as a design for all sites.

Permen PU 29/2006 · Bab III.3.1.d

1 footing
2 ground

Width is worked out, not fixed. Footing width works the same way. It comes from bearing and settlement sums, “per standard soil-mechanics theory”. The method lives in SNI 8460, the national ground design standard. Get your width from a geotechnical engineer working to that standard. It depends on your soil and your load.

Concrete grade and rebar cover: see SNI 2847. The rule does not name a concrete grade. It points to SNI 2847, the national concrete design standard, current edition. Rebar cover sits in the same standard. We are not printing an MPa or mm figure here. Sources we checked did not agree on what SNI 2847 says. Until we confirm it against the standard’s own text, we will not guess. Ask your structural engineer, or check SNI 2847 yourself.

Thickness needs a design check. Do not assume there is no minimum in the applicable concrete standard. The engineer checks punching shear, one-way shear and bending for your exact footing. The rule does not give a set 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: 0.5 m.
Concrete thickness, measured from its top to its underside: 0.6 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 × 0.5 × 0.6 = 7.2 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

Part of the Indonesian building-rules hub. One national rule book, plus the tools that work to it.
Setting out the stairs on the same build? See Indonesian stair rules.

Sources

Permen PU No. 29/PRT/M/2006 (Pedoman Persyaratan Teknis Bangunan Gedung), Bab III.3.1.d (foundation depth set by ground/site investigation, concrete and rebar deferred to SNI 2847, width deferred to soil-mechanics calculation). Read it at peraturan.bpk.go.id.
SNI 2847:2019 (Persyaratan Beton Struktural untuk Bangunan Gedung, BSN) — the referenced concrete-design standard for grade and cover figures, not independently confirmed for this page. Catalogue at bsn.go.id.
SNI 8460:2017 (Persyaratan Perancangan Geoteknik, BSN) — the referenced geotechnical standard for footing-width calculation, not opened during research for this page. Catalogue at bsn.go.id.

Read this first. PP 16/2021 implements the Building Law UU 28/2002. Check it with the current ministerial rules and SNI standards. The full current text set was not obtained for this guide. Do not infer that no minimum thickness, grade or cover applies. Get these from the engineer’s design before you build.

Frequently asked questions

Is there a minimum foundation depth in Indonesia?

Get the depth from the site design. Soil, loads, water and climate need checking. The full current national rules and referenced SNI texts still need review. Do not infer that no minimum applies from a general climate label.

How wide does a footing need to be?

There is no fixed width in this rule. Width comes from bearing and settlement sums, per standard soil-mechanics theory. The method sits in SNI 8460, the national geotechnical design standard. Get your width from a geotechnical engineer working to that standard, not from a number on a website.

What concrete grade goes in a footing?

The rule points to SNI 2847, the national concrete design standard, current edition. It does not name a grade itself. Sources we checked did not agree on what SNI 2847 sets, so we are not printing an MPa figure until we confirm it against the standard. Ask your structural engineer, or check SNI 2847.

What about rebar cover?

Same story. Cover is set inside SNI 2847, not in the building rule itself. So we are not printing a cover figure here either. The reason matches the concrete grade: it needs checking against SNI 2847's own text first. Ask your structural engineer for your job's cover.

Is footing thickness fixed?

No. Minimum thickness is not a set figure in the rule. It is a design output. The engineer checks punching shear, one-way shear and bending for your exact footing. You cannot read the number off the regulation.