Why choose Avenir Renovations?
Why insulate now?
Insulating is not just about “putting in insulation”: it is about treating the coherent envelope of your home for immediate and lasting gains. In the province of Liège, many homes built before the 1990s have structural improvement margins (poorly insulated attics, hollow walls, insufficient ventilation).
- Thermal comfort: warmer walls in winter, rooms less prone to overheating in summer.
- Lower bills: less heat loss, simplified heating adjustments.
- Silence. Insulation and sealing reduce street noise and internal resonances.
- Property value: improved EPB trajectory and a more attractive home for resale/rental.
Working method: your work in 5 steps
An effective insulation depends as much on the method as on the material. We mark each phase, document the choices, and keep a clean site to limit disturbances.
Our insulation solutions
Each building imposes its method: type of walls, humidity, access, urban planning constraints. We offer clear options (materials, thicknesses, finishes), explained step by step to avoid later revisions.
- Priority No. 1. The roof concentrates the highest heat losses; we install two crossed layers when possible, with continuous vapor barrier and watertight junctions around openings.
- Converted attics. Insulation under slopes (mineral wool/wood, PIR) with continuity at the eaves/peak.
- Unconverted attics. Blowing of loose insulation (cellulose/wool) for quick and effective implementation.
- Sarking. External insulation during a roof renovation: continuous solution, ideal against thermal bridges.
- Interior. Gyproc/Fermacell linings with treatment of thermal bridges and strict air barrier to prevent condensation.
- Exterior (ETICS). Insulating facade that eliminates many thermal bridges and offers a new rendering; to be studied according to urban planning.
- Cavity walls (injection). Typical in Belgium when a cavity exists; injection of EPS beads, PU foam or mineral wool after surveys.
- Ground floor subfloor. Insulation by the basement/garage ceiling (panels, sprayed foam) to eliminate the "cold floor" effect.
- Underlay & sub-layers. Insulating screed or effective underlay during a floor change; specific solutions in ventilated crawl space depending on accessibility.
- Warm roof or inverted depending on configuration, with careful vapor barrier, slopes ≥ 2 %, upstands at the right height and sized drainage.
- Continuous sealing. Membranes, strips and sleeves at frame/wall connections, hatches, ducts and penetrations.
- Control. Blower door (infiltration test) possible to check and correct.
- Controlled ventilation. Extraction of humid rooms, VMC single or double flow depending on the dwelling, with regulated flows and airtight networks.
- Rock wool / glass wool. Versatility and good performance/price ratio.
- PIR / PUR. High performance at low thickness (roofs/technical linings).
- Cellulose / wood fibers. Summer comfort and hygro regulation.
- EPS / XPS. ETICS, floors, flat roofs according to systems.
- Cork panels. Thermal/acoustic corrector in specific areas.
Prices for insulation work in Liège (including VAT)
Prices depend on the area, access, thicknesses, and finishes. A detailed quote always follows a technical visit. Indicative benchmarks for the province of Liège:
| Item | Price indication (including VAT) |
| Roof insulation (under slopes / attics) – insulation + installation | 40 to 90 €/m² |
| Flat roof insulation (complete system) | 70 to 140 €/m² |
| Internal wall insulation (excluding finishes) | 50 to 100 €/m² |
| External insulating facade (ETICS) | 130 to 220 €/m² |
| Cavity walls – insulation injection | 20 to 45 €/m² |
| Ground floor insulation (basement/garage ceiling) | 25 to 60 €/m² |
| Insulating screed / performance underlay (depending on system) | 20 to 50 €/m² |
| Sealing / air tightness (fixed price depending on area) | 8 to 20 €/m² |
| Air tightness test (blower door) | 350 to 700 € |
| Single flow VMC (single-family house) | 2,500 to 6,000 € |
| Double flow VMC (single-family house) | 5,000 to 10,000 € |
The quote takes into account access (city center, alleys), scaffolding, and interfaces with other lots (frames, plastering, facades).
Subsidies (Wallonia – 2025-2026): what you need to know
Since February 14, 2025, Wallonia has implemented a temporary scheme for Housing Subsidies (valid until September 30, 2026). The visit of a Housing auditor remains the entry point for most subsidies (insulation, frames, heating, ventilation). The amounts are adjusted according to your income through categories R1 to R5 (which correspond to a multiplier on a base amount). We prepare your file (detailed quotes, implementation photos, technical sheets) and guide you through the steps.
Process at a glance
- Housing Audit by an accredited auditor (unlocks access to subsidies related to recommendations).
- Submission of subsidy applications for the audit and then for the works via My Space (RW site) before 30/09/2026.
- Works carried out by a contractor registered with the BCE, with compliant electricity/gas (prerequisite).
- The subsidies cover part of the VAT-inclusive invoice (ceilings of 50% or 70% depending on your income category).
Useful points of attention
- The audit is not mandatory for certain roof works (e.g. health) and for roof insulation; but it is still recommended to structure the process and maximize assistance.
- If the auditor recommends related works on the same wall (e.g. health + roof insulation), the application must cover the entirety of the related works to be eligible for subsidies.
- Keep “before/during/after” photos and retain technical sheets (specific eligibility criteria).
Additional aids
- Zero-interest loans: Rénopack (with subsidies included) and Rénoprêt (without audit/subsidy), through the Walloon Social Credit Company (SWCS) or the Walloon Housing Fund (FLW), depending on your family situation.
Urban Planning, Energy Performance & subsidies (Liège / Wallonia)
Interior works are often exempt from authorization; a change of appearance (ETICS, plaster visible from the street) may require a prior urban planning declaration (DUP) or a urban planning permit (PU) depending on the municipalities.
Regarding Energy Performance, we document the works (technical sheets, implementation photos) to recognize the gains.
For the subsidies, we frame the process (audit/justifications) and gather the necessary documents to maximize assistance when applicable.
Why choose Avenir Rénovations Liège?
You benefit from a single point of contact who prioritizes high-impact actions and coordinates the trades. Our added value: meticulous installation, clear options, and clean finishes, without compromising on air tightness.
- Clear prioritization: roof first, then walls/floors and appropriate ventilation.
- Measurable quality: checklists, blower door possible, air barrier continuity checks.
- Transparent quotes: quotes by lots with options, phased schedule, and progress photos if desired.
- Multi-trade coordination: insulation, frames, MVHR, plastering/painting, electricity.
- After-sales service & advice: equipment maintenance (MVHR filters), periodic inspections.
Frequently Asked Questions
Before starting insulation, you may have questions about priorities, condensation risks, the benefits of cavity walls, or the procedures. Here are practical answers tailored to the Liège context.
Interior insulation or insulating façade (ETICS): which to choose?
Interior is quick, modular "room by room", ideal for apartments. The exterior (ETICS) offers the most uniform performance and a new facade, but may require permission. We compare the two based on your street, your frames, and your schedule.
Are cavity walls always injectable?
No. It is necessary to check the presence/width of the cavity, the condition of the joints, and the absence of moisture. When possible, injection provides an excellent cost/gain ratio and a quick project. We conduct surveys before making a decision.
Can insulation cause condensation?
If air tightness and ventilation are neglected, yes. That’s why we ensure the continuity of the vapor barrier/air barrier and size the extractions; the result is a healthier home (warmer walls, less condensation).
Should you insulate before replacing the boiler or installing a heat pump?
In the vast majority of cases, yes. By reducing needs, you choose a lower power and use more comfortable low temperature emitters.
Can you live in the house during the work?
Most often, yes. Interventions by zones (attics, basement ceiling, linings) are phased to limit dust and noise. For an insulating façade, we organize access, protections, and a schedule compatible with your daily life.
Are you considering insulation work in Liège?
Benefit from a clear study, a detailed quote, and a careful installation by local teams.
Contact Avenir Rénovations Liège to gain comfort all year round and stabilize your consumption.
Agency Avenir
Rénovations
for Insulation work in Liège
An expert to take charge of your renovation projects and guarantee deadlines, budgets and quality of all services.
Insulation work in Liège and everywhere in France
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