Construction Growth and Architectural Glass Demand in Southeast Europe

Construction is the largest source of demand for architectural glass in Southeast Europe, but the region does not move as one market. Construction output is rising strongly in Slovenia, Romania and Bulgaria, building permits are cooling in Croatia, and Greece and Romania are channelling public money into the renovation of older housing. Each of these indicators affects a different part of the glazing market: new-build windows, curtain walls and façades for commercial buildings, and replacement windows with energy-efficient glass.

This article compares four indicators across the region: construction output, building permits, renovation programmes and investment in commercial and residential buildings. It then explains how each one translates into demand for windows, curtain walls and high-performance glazing. EU members (Romania, Bulgaria, Croatia, Slovenia, Greece) report harmonised data through Eurostat, while Western Balkan figures come from national statistical offices, so comparisons across the two groups should be made with care.

Construction output: strong growth, but not always in buildings

Eurostat’s monthly index of production in construction shows Southeast Europe outperforming the EU average in 2026. In June 2026, Slovenia (+22.9%) and Romania (+18.4%) recorded the highest year-on-year increases among EU member states. Bulgaria grew 4.4% year-on-year and has stayed in positive territory every month since the start of 2026. Slovenia (+29.6%) and Romania (+9.4%) were also among the top performers in March 2026. (Eurostat, BCCI)

These headline figures need to be read carefully. The index combines buildings, civil engineering and specialised works, and much of the regional growth comes from roads, energy and utilities, which use little architectural glass. At EU level, construction of buildings fell 6.5% year-on-year in the euro area and 4.9% in the EU in June 2026, even as total output rose. For glass demand, the buildings sub-index is the relevant series.

Outside the EU, Serbia shows the same split. In the first quarter of 2026, the value of construction works rose 1.7% at current prices but fell 5.0% at constant prices. Within that total, works on buildings rose 25.4% while other constructions fell 21.5%. (Republic Statistical Office of Serbia, RZS) Croatia and Greece are often missing from Eurostat’s early monthly estimates, so their national releases are the better source.

Building permits: the pipeline for new windows and façades

Building permits are the best leading indicator of new-build glazing demand, because windows and façades are installed roughly one to two years after a permit is issued. Across the region, the permit pipeline is mixed.

Bulgaria is expanding. In the second quarter of 2026, municipalities issued permits for 2,216 residential buildings with 11,499 dwellings and 1.35 million m² of gross building area. Residential permits rose 8.2% year-on-year and dwellings 14.0%, while the floor area of permitted non-residential buildings grew 42.2%. Plovdiv, Sofia, Varna and Burgas led activity. (NSI Bulgaria)

Romania is growing modestly. Authorities issued 34,602 residential permits in January–November 2025, up 4.4% year-on-year, mostly for individual houses. In the first half of 2025, permitted retail space rose 53% to 303,000 m², and the category covering offices, industrial and logistics buildings grew 5.7% to 1.48 million m². Permits in Bucharest, however, have fallen sharply over the past three years. (INS via ZF English, Romania Insider)

Croatia is cooling. The number of permits issued in January–June 2026 was 14.3% lower than a year earlier, with June permits covering 1,467 planned dwellings. (Croatian Bureau of Statistics) Greece shows fewer but larger projects: over the twelve months to January 2026, permits fell 0.5% and surface area 4.9%, while building volume rose 3.8%. Greek permit data also include repairs and renovations, which makes them useful for tracking the replacement market. (ELSTAT via To Vima)

In the Western Balkans, Serbia issued 2,634 permits in March 2026, up 19.3% year-on-year, covering 3,123 apartments. Most of these apartments, 82.7%, will be in buildings with three or more units, the segment that drives standardised window and balcony-glazing orders. (RZS via ICE) In Albania, permits rose to 322 in the first quarter of 2026 from 258 in the previous quarter, still below the peak of 509 in Q2 2023. INSTAT’s residential construction cost index stood at 114.1 in Q4 2025, up 1.2% year-on-year. (Trading Economics, based on INSTAT, INSTAT)

Renovation programmes: the replacement market

Renovation drives demand for replacement windows, and in Southeast Europe it is heavily shaped by public funding. Greece’s housing stock is old: of 6.6 million homes counted in the 2021 census, only 770,000 (11.6%) were built after 2001. More than 100,000 households have upgraded their homes through the Exoikonomo energy-saving programmes, which have received combined funding of over €1.4 billion. Approved projects now have until 30 November 2026 to finish. (ICE, OT.gr) A new “Renovate” programme of about €500 million targets 15,000 to 20,000 homes, mainly apartments from the 1980s and 1990s, and explicitly covers windows and doors.

Romania’s revised Recovery and Resilience Plan includes €2.9 billion for energy-efficiency renovation and seismic strengthening of residential and public buildings, supplemented by REPowerEU household vouchers of up to €20,200. (IEA) Public tenders show what this means in practice: a 2026 apartment-block retrofit in Geoagiu specifies the replacement of all exterior joinery with energy-efficient triple-glazed PVC windows. (Patterno, TED tender) A €400 million European Investment Bank facility, open from January 2026 to September 2029, aims to support energy upgrades of more than 12,500 buildings in Central and Eastern Europe, including Romania. (Forbes Romania)

Regulation reinforces this trend. The Energy Performance of Buildings Directive requires member states to set minimum energy performance requirements for replacement building elements such as windows, and Romania’s deadline to transpose the 2024 revision was 29 May 2026. (Glass for Europe, Playtech) A study commissioned by Glass for Europe found that almost half of the potential energy savings from high-performance glazing could be achieved within ten years if the window replacement rate doubled from 2% to 4% a year. (Glass Worldwide)

Investment in commercial and residential buildings

Commercial real estate investment determines demand for the most glass-intensive building types: offices, hotels and retail centres with curtain walls and structural glazing. In 2025, commercial property investment across six core CEE markets reached €11.6 billion, up 31% year-on-year. Southeast European markets remained small within that total: Romania recorded about €500 million despite strong occupier demand, and Bulgaria held at about €400 million ahead of joining the euro in January 2026. (Colliers via Business Forum)

Offices dominate investment in parts of the region. In the first half of 2025, offices accounted for 70% of investment volume in Bulgaria and 41% in Serbia, while retail led in Romania. (Cushman & Wakefield Echinox) CBRE reported that offices represented 62% of Southeast European transactions in late 2025, with Serbia the most active market, although quarterly volumes fell 53%. (CBRE)

Transaction volumes measure the purchase of existing assets, not new construction. They are, however, a useful signal of investor confidence, which in turn affects whether new office and hotel projects with large glazed façades go ahead. Residential investment is better tracked through permits and dwelling completions, such as Bulgaria’s 1,269 residential buildings completed in Q2 2026. (NSI via Moody’s Analytics)

How these indicators shape demand for windows, curtain walls and energy-efficient glazing

The European flat glass market was valued at about US$20.5 billion in 2025, with construction its largest end use and insulating glass its largest product type. (Research and Markets, IMARC) Within Southeast Europe, each construction indicator feeds a different part of that demand.

• Residential permits lead demand for windows and balcony glazing by one to two years. Multi-unit buildings, which dominate Serbian and Bulgarian permits, generate large, standardised orders for PVC and aluminium windows with insulating glass units.
• Non-residential permits and commercial investment drive demand for curtain walls, structural glazing, solar-control and laminated safety glass. This segment carries the highest value per square metre but is the most sensitive to investor sentiment.
• Output in the buildings sub-index shows when glazing is being installed. Growth that comes mainly from civil engineering, as in parts of Romania and Serbia, adds little to glass demand.
• Renovation programmes create a replacement market that is less cyclical than new construction. Funding conditions and EPBD minimum requirements shift the product mix from basic double glazing towards low-E double and triple glazing, raising the value of each window.
• Construction cost indices can delay projects that already hold permits, weakening the link between the permit pipeline and actual installations.

None of these indicators measures glass consumption directly. Actual demand depends on the split between new build and renovation, building types, glazing specifications and the glass area per project.

The regional outlook

The evidence points to three distinct situations rather than one regional trend. Bulgaria and Serbia have expanding residential permit pipelines, which support new-build window demand into 2027. Romania and Greece combine moderate new construction with large, publicly funded renovation programmes that favour energy-efficient replacement glazing. Croatia’s falling permits suggest slower new-build demand in the near term.

For glass processors and window manufacturers, the strongest opportunities lie where renovation funding and stricter energy rules meet: insulating units with low-E coatings, triple glazing, and solar-control glass for southern climates. Curtain-wall demand will follow office and hotel development in the main cities, where investment volumes remain modest and uneven.

A clearer assessment will require data that separate buildings from civil engineering, new build from renovation, and residential from non-residential projects. Harmonised statistics are also still missing for much of the Western Balkans, where national permit and output series remain the main source.