Historic wall AL GK — framing installation (vertical section)

Junction function

Heritage AL GK insulation on framing = adhesive variant (p. 52) when direct bonding is not feasible:

• Uneven internal wall (deviation greater than 10 mm/m) — framing levels the plane.
• Unstable plaster — detaching, flaking, mouldy → adhesive will not hold.
• Concealed services required (cables, pipes) → space within the framing.
• High wall moisture — a 2–3 cm gap between the wall and the insulation allows the structure to ventilate.

Framing as for conventional plasterboard but thicker by the insulation thickness:

• CD60 + UD + longer hangers — for AL GK 50+12.5 mm, a profile depth of 70–80 mm is needed.
• Or timber 50×60 mm fixed to the wall with chemical anchors (heritage = chemical or mechanical anchors, NOT expansion plugs which crack the masonry).

Critical installation aspects

• Framing (item 04) — impregnated timber or steel CD60+UD profile; vertical spacing 40–60 cm (as for plasterboard); anchored to masonry with chemical anchors (Hilti HIT-RE 500 / Fischer SuperBond).
• Space between wall and AL GK board = natural ventilation of the wall structure (2–3 cm); assists with moisture balance in old walls lacking horizontal damp-proofing.
• No insulation within the framing cavity — unlike typical plasterboard with mineral wool inside, here the cavity remains empty (air acts as additional insulation).
• AL GK board (item 05) fixed to profiles with screws — analogous to plasterboard; 3 mm expansion gap between boards, joints filled with jointing compound.
• Perimeter gap (item 09) — low-expansion PIR foam; decorative cover trim (item 10).
• Thermal bridging through framing — timber (λ ≈ 0.13) or steel (λ ≈ 50!) creates point thermal bridges; steel is thermally worse — prefer timber where the building is highly energy-efficient. Steel CD60 = 5–8% loss of insulation effectiveness.

Documentation

Technical Catalogue termPIR® — Residential Buildings (Gór-Stal 2022), page 52 — Historic wall AL GK, vertical section, framing installation. Scale 1:10.

Components in this junction