Three-layer wall with termPIR® AL — typical section

Junction function

Three-layer wall = the Polish single-family house standard of the 1990s: load-bearing leaf + insulation layer + outer leaf. Vs ETICS (p. 36):

• Durability: 80+ years (clinker requires no renovation), vs ETICS 25–30 years (render + decorative trim).
• No painting work on the facade — clinker / silicate is a maintenance-free facade.
• Better acoustics — masonry mass ~400 kg/m² (vs ETICS ~100 kg/m²).
• Required footprint — wider by 6–12 cm (the full outer leaf is added).
• Initial cost — 30–50% higher than ETICS, but over a 30-year period equivalent (zero renovation).

With termPIR® AL (item 02) as insulation:

• λD = 0.022 W/m·K = a thinner layer than EPS/MW at the same U-value.
• Aluminium facing on both sides = vapour tightness + resistance to installation damage.
• No fire issues — in a three-layer wall PIR is enclosed within the masonry (no air contact), so the reaction-to-fire class is secondary.

Critical installation aspects

• Wall ties (item 05) — stainless steel (NOT galvanised!) with a thermal break such as Thermomaß / Halfen MBA; spacing 50 cm vertically, 75 cm horizontally + additional at corners every 30 cm.
• termPIR® AL board (item 02) in the cavity: bonded to the load-bearing leaf with PUR foam adhesive full-surface or fixed with spacers (50×50 cm spacing) so as not to block the thermal performance of the structure.
• Slope towards the interior of the cavity — for clinker outer leaves, weep holes in the joints every 50 cm are recommended (ventilation of condensation in the cavity).
• Horizontal damp-proof course (item 04) MUST BE at floor level — torch-on bitumen membrane; without it capillary rise of water from the foundations occurs = salt efflorescence on clinker (white patches).
• Floor ring beam (items 07, 13) — thermal break required; a termPIR® AL strip 30–50 mm or a Schöck Isokorb beam in Filigran slabs.
• Thermal bridge at the slab/balcony interface — in single-family houses the balcony slab is typically a thermal bridge; a termPIR® AL strip in the lintel zone of the ring beam reduces ψ from 0.5 to <0.1 W/m·K.

Documentation

Technical Catalogue termPIR® — Residential Buildings (Gór-Stal 2022), page 38 — External three-layer wall, typical section. Scale 1:10.

Components in this junction