Deemed-to-comply (AS 2870)
AS 2870 deemed-to-comply is the tabulated footing design route for standard reactive sites. Distinct from NCC's DTS pathway. Common source of submission confusion.
Ask Chalkline about this →Deemed-to-comply is the tabulated standard-design route in AS 2870:2011, Residential slabs and footings (verified 2026-05-15). For residential sites classified in the standard’s site classifications (Class A, S, M, H1, H1-D, H2, H2-D and certain Class P variants), AS 2870 publishes prescriptive footing tables that, if followed, are deemed to comply with the standard without site-specific engineering analysis. The builder or the engineer reads off the appropriate raft or strip footing detail from the table for the site classification, the wall construction type, and the dwelling configuration.
Not the same as NCC Deemed-to-Satisfy (DTS). The naming is identical at three syllables and the concepts are related (both are prescriptive compliance pathways rather than performance-based), but they sit in different documents and cover different things:
| Term | Source | Scope |
|---|---|---|
| Deemed-to-comply (this article) | AS 2870:2011 | Tabulated residential footing designs for standard reactive sites |
| Deemed-to-Satisfy (DTS) | NCC 2022 Volume One and Volume Two | The DTS solutions schedule across the whole code: structural, fire, energy, accessibility, plumbing, etc. AS 2870 deemed-to-comply footings are themselves a DTS provision when called up by NCC Part 4 |
The crossover: AS 2870’s deemed-to-comply footings are one of the routes by which a residential project’s footings achieve NCC DTS compliance. So a slab detailed from AS 2870 deemed-to-comply tables is both deemed-to-comply (under AS 2870) and DTS-compliant (under NCC).
Where deemed-to-comply does not apply:
- Class P (problem) sites: site-specific engineering required.
- Highly reactive sites with controlled fill: engineer’s design typically required.
- Buildings outside AS 2870’s residential scope (large warehouses, industrial slabs, multi-storey buildings beyond Class 1).
- Footings supporting unusual point loads (heavy steel goalposts, large rainwater tanks within the building footprint) where the table assumes uniform loading.
The submission-time confusion to avoid: writing “deemed-to-comply with NCC” when you mean “AS 2870 deemed-to-comply detail used as the DTS footing solution”. The certifier reads them as different statements.
Also known as: AS 2870 standard design; tabulated footing design; AS 2870 prescriptive footing.
Category: Compliance.
Related
See also
- Strip footings (practical install)
- Raft footings
- Conventional reinforced slab
- Pre-pour slab inspection
Last updated: 2026-05-15. Verified: 2026-05-15. Quarterly review for currency.