Ahmet Alptekin Kasar
Founder, Managing Director
Updated: 2026-11-03
This guide is for facade contractors, design-office teams, developers, energy consultants and builders' merchants working in Hungary. It walks through a ventilated rainscreen facade layer by layer and shows which fire and moisture figures apply to each layer. The fire strategy of the facade is set by the fire designer and the build-up by the designer. We supply the materials.
What the Hungarian fire code says
The national fire code, Decree 54/2014 (XII. 5.) BM (OTSZ, in Hungarian), § 25 (1), sets the reaction-to-fire class of the facade insulation material. In Hungarian: „a) átszellőztetett légréssel kialakított külső térelhatároló fal esetén A1–A2 – a lábazat kivételével –, b) lábazati felületen A1-E”. In our translation: on an external wall built with a ventilated air gap, A1–A2, except at the plinth; on the plinth surface, A1–E.
Two more points belong here. Under § 24 (1) b), protection against fire spread on the facade includes, for walls with an air gap, preventing fire spread inside the air gap. Under § 26 (1) c), a facade fire spread limit applies, among other cases, to the external wall where ventilated cladding, coating or rendered insulation systems of class A1–D are used (our translation).
So the decree sets a class for the insulation behind the gap and attaches further conditions to the gap and the cladding. What that means on a given building, for example a fire barrier in the air gap, is for the fire designer to decide. Under the OTSZ, A1 and A2 materials count as non-combustible; our article on reaction to fire classes explains the classes.
| Layer | Product | Class / value | Source |
|---|---|---|---|
| Insulation behind the air gap | requirement | A1–A2, except at the plinth | OTSZ § 25 (1) a) |
| Insulation at the plinth | requirement | A1–E | OTSZ § 25 (1) b) |
| Mineral wool board | ODE Rockflex ETICS Board (YL120: 30–100 mm, R 0.85–2.85 m²K/W) | class “A”, non-combustible (according to EN standard); μ = 1; exact class on the DoP | ODE brochure pp. 45 and 47 |
| Mineral wool board | ODE Starflex board (λD 0.031–0.040 W/(m·K)) | A1: unfaced, glass tissue, woven glass textile, AFH alu foil faced; AFK: C-s1,d0 | ODE DoP No 101 |
| Air gap | open at bottom and top, insect mesh | – | general rule; ODE brochure p. 16 (Figure 5: "Ventilation Space") |
| Substructure | brackets and metal profile | – | ODE brochure p. 16 (Figure 5: "Profile (Metal)") |
| Outer board | Dalsan BoardeX, 12.5 and 15 mm, GM-FH1R | A1 (EN 13501-1); μ = 10; total water absorption ≤ 5 % (H1) | BoardeX DoP AL 003 |
The layers from inside out
Wall. The structural wall carries the brackets and the insulation fixings. The type and spacing of fixings follow the system and the wall material.
Mineral wool board on the wall. The ODE brochure says the Rockflex ETICS Board is "used in the cladding of exterior building façades" and adds: "They are used for thermal, sound, and fire insulation of curtain walls." (p. 47) The YL120 type comes in 30–100 mm with R 0.85–2.85 m²K/W. The brochure's glass wool chapter mentions the same construction: glass wool wall boards "placed between profiles in curtain wall details", and where there is even a slight possibility of water exposure, "water repellent silicone containing glass wool wall boards should be used" (p. 16). Its "Figure 5 – Curtain Facades" names the layers: exterior facade covering, ventilation space, metal profile, insulation material, wall.
The boards lie tight against the wall, without gaps and with staggered joints. No air channel may remain between board and wall, or cold air gets behind the insulation. The boards are anchored as the system specifies.
Air gap. The gap is open at the bottom and the top so air can rise through it and carry moisture away. Insect mesh closes the openings. The wool must not bulge into the gap, and nothing should narrow it. Fire-spread measures inside the gap are decided by the fire designer under OTSZ § 24 (1) b).
Substructure. Brackets are fixed to the wall and pass through the insulation; the vertical metal profiles sit on them. Every bracket is a point thermal bridge, so their spacing and any separation between bracket and wall follow the system.
Outer board. The Dalsan BoardeX declaration of performance (AL 003) classifies the board A1 under EN 13501-1. It is made to EN 15283-1:2008+A1:2009, type GM-FH1R, in 12.5 and 15 mm. Among its intended uses the DoP lists exterior drywall systems, soffits and curtain walls. The manufacturer's data sheet describes BoardeX as an exterior sheathing board used as a "backerboard" under metal, siding, timber or decorative brick cladding, and lists ventilated facade systems among its uses. The data sheet also describes a mineral render system reinforced with alkali-resistant mesh on the board.
A few rules from the data sheet: BoardeX is not a waterproofing material; it is fixed to the profiles with corrosion-resistant BoardeX screws at no more than 20 cm spacing; joints are staggered; and an external wall built with it needs a condensation analysis for its climate zone. Our BoardeX vs impregnated plasterboard comparison and our BoardeX A1 board analysis (in Hungarian) go into the board in more detail.
Vapour: more open towards the outside
The basic moisture rule for the facade is that layers become more vapour-open towards the outside, so vapour leaving the wall escapes through the air gap. The brochure gives Rockflex μ = 1 (p. 45). The BoardeX DoP declares μ = 10. The ODE Starflex DoP lists this property as "NPD".
The wool has to be protected against wind and driving rain from the gap as the system requires. For locations exposed to water the brochure calls for water-repellent, silicone-containing glass wool boards (p. 16), and it describes the Rockflex ETICS Board as containing a water-repellent admixture (p. 47). If the system asks for a wind barrier over the wool, its fire class also needs the fire designer's approval.
Thermal requirement
Annex 1 of Hungary's Decree 9/2023 (V. 25.) ÉKM (in Hungarian) sets U ≤ 0.24 W/m²K for an external wall. Our U-value calculation guide shows how to work out the thickness. For single-family house measures claimed under the EKR scheme, data sheet 1.3 also has a facade condition: for a facade system, at least 15 cm with λ ≤ 0.038, or 12 cm with λ ≤ 0.032 (Decree 41/2025 (XII. 30.) EM, Annex 1, 1.3.1.1 h). Material choice on facades is discussed in our stone wool vs glass wool facade article and in the EPS vs stone wool facade systems comparison (in Hungarian).
Material supply for contractors
For facade work we supply ODE Rockflex stone wool boards, ODE Starflex glass wool and Dalsan BoardeX boards. The declarations of performance come with the quote; our DoP and CE documents guide explains what to check on them. Road transit from Türkiye to Hungary takes 3–5 days, about 5 on average. When the material is not in stock, lead time is typically 1–2 weeks. We deliver across Hungary.
The two mineral wools also compete in the loft; our loft-floor comparison sets out the differences there.
Send us the facade area and the planned build-up, and we will put together a material list with the DoPs: contact · +36 30 485 0258 · info@euconx.com. We reply the same working day.
Frequently asked questions
What fire class must insulation have in a ventilated facade in Hungary?
Under OTSZ § 25 (1) a), the facade insulation material on an external wall built with a ventilated air gap must be class A1–A2, except at the plinth. On the plinth surface, point b) allows A1–E. The fire designer decides the details.
Stone wool or glass wool in a ventilated facade?
The ODE brochure recommends the Rockflex ETICS Board for thermal, sound and fire insulation of curtain walls and also mentions glass wool wall boards between profiles, calling for water-repellent, silicone-containing boards where water exposure is possible. In both cases the class on the DoP of the type delivered has to match the design.
Is BoardeX an A1 board?
Yes. The Dalsan BoardeX declaration of performance (AL 003) gives class A1 under EN 13501-1 for a GM-FH1R board made to EN 15283-1:2008+A1:2009.
Can BoardeX be used as waterproofing?
No. The manufacturer's data sheet states that BoardeX must not be used as a waterproofing material. The board carries the cladding or the render system.
Why does the air gap stay open at the top and bottom?
Air rises through the gap and carries moisture out from between the wool and the cladding. Insect mesh closes the openings. Any fire measures needed in the gap are decided by the fire designer.
What U-value does a facade wall need in Hungary?
Decree 9/2023 (V. 25.) ÉKM sets U ≤ 0.24 W/m²K for an external wall. The insulation thickness needed depends on the λ of the chosen material.
Sources
1. Decree 54/2014 (XII. 5.) BM (OTSZ), § 24 (1) b), § 25 (1), § 26 (1) c), Annex 1 point 101, National Legislation Database (in Hungarian; the English wording above is our translation): https://njt.jog.gov.hu/jogszabaly/2014-54-20-0A
2. Decree 9/2023 (V. 25.) ÉKM, Annex 1 (maximum U-values), National Legislation Database (in Hungarian): https://njt.jog.gov.hu/jogszabaly/2023-9-20-8X
3. Decree 41/2025 (XII. 30.) EM, Annex 1, point 1.3.1.1 h), Magyar Közlöny 2025/160 (in Hungarian): https://magyarkozlony.hu/hivatalos-lapok/p1UZBNSoHiBBftW595F66949b7f7ae914/dokumentumok/5858f900426cb56e532a468a989dbb1417d9aef0/letoltes
4. ODE Building Insulation brochure: glass wool boards in curtain walls and "Figure 5 – Curtain Facades" (p. 16), Rockflex class "A" and μ = 1 (p. 45), Rockflex ETICS Board (p. 47): https://ode.com.tr/_upload/pdf/ode_building_insulation_brochure_3.pdf
5. ODE Starflex / Lunaflex / Evomineral declaration of performance No 101 (board λD, reaction to fire, NPD): https://ode.com.tr/_upload/pdf/GLASSWOOL_BLANKET-BOARD_DECLARATION_OF_PERFORMANCE_-_EN_13162.pdf
6. Dalsan BoardeX declaration of performance AL 003 (A1, EN 15283-1:2008+A1:2009, GM-FH1R, μ = 10, water absorption ≤ 5 %; in Turkish): https://dalsan.com.tr/CmsFiles/Documents/Boardex_DOP_Ankara_TR_.pdf
7. Dalsan BoardeX product data sheet (uses, fixing, warnings; in Turkish): https://dalsan.com.tr/CmsFiles/Documents/boardex_foy_tr.pdf
8. EuConX company data (transit, lead time, reply time, delivery across Hungary)
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