S.R.21 2014 + A1: 2016 ANNEX E - T1 - Structural
SR21 Annex E T2 Perm is a free-draining, open-graded crushed limestone produced in accordance with Transport Infrastructure Ireland (TII) specifications for unbound granular materials.
It is designed as a permeable sub-base layer, providing rapid water drainage while maintaining load-bearing strength beneath roadways, yards, and permeable paving systems.
This material is typically used in drainage layers, permeable pavements, and foundation construction where moisture control and stability are critical.
SR21 Annex E T2 Perm aggregates comply with EN 13242: Aggregates for unbound and hydraulically bound materials and are certified under S.R. 21: 2021 +A1: 2023 Annex E (Table E.1, T2 Perm).
Typical Characteristics
Property | Specification |
|---|---|
Type | Open-graded crushed limestone (permeable sub-base) |
Typical Size Range | 4 – 20 mm or 10 – 40 mm (depending on project spec) |
Compliance Standard | S.R. 21 Annex E T2 Perm (EN 13242) |
Use | Free-draining sub-base, filter layer, foundation drainage |
Compaction | Good – interlocking while maintaining voids |
Permeability | High – promotes efficient water flow and filtration |
Key Benefits
Excellent water permeability and filtration performance
Maintains load-bearing capacity while reducing water retention
Reduces risk of frost damage and surface ponding
Fully compliant with SR21 Annex E T2 Perm and EN 13242
Applications
Permeable paving systems and sustainable drainage (SuDS)
Filter drains and soakaway construction
Driveways, yards, and road bases requiring rapid water escape
Under-slab drainage and landscaping features
Sub-base layer where water movement and load-support are both required