You have just renovated or built new — and it smells. Of paint, of chemicals, of "new". These are in all probability VOC: volatile organic compounds off-gassing from fresh building materials. In most cases this is unpleasant but harmless. In some cases it is not.
VOC (volatile organic compounds) encompass hundreds of different substances — formaldehyde, toluene, xylene, styrene, limonene, and many more. They off-gas from paints, varnishes, adhesives, floor coverings, furniture, and sealants.
Where VOC Come From
In the buildings we assess after a renovation, we find the most common VOC sources at these locations:
- Paints and varnishes: Even "solvent-free" products off-gas measurably in the first few weeks.
- Floor coverings: Vinyl, laminate, and their adhesives. Especially parquet adhesive and sealants.
- Furniture: Chipboard, MDF — especially in budget furniture. Main source of formaldehyde.
- Insulation and foam sealants: PU foams, XPS panels.
- Silicone sealants and joint compounds: Fresh silicones off-gas acetic acid or oximes.
The good news: most VOC concentrations fall by around 80% in the first 4–8 weeks. The bad news: some sources — especially formaldehyde from chipboard — continue to off-gas for months or years.
When VOC Are a Problem
Not every smell is dangerous. But persistent complaints such as headaches, dizziness, mucous membrane irritation, nausea, or concentration problems after a renovation should be taken seriously.
Formaldehyde is the most critical individual substance — classified by IARC as a Group 1 carcinogen. WHO recommends a guideline value of 0.1 mg/m³ in indoor air.
For total exposure: a TVOC value (total VOC) below 300 µg/m³ is hygienically acceptable. Between 300 and 1,000 µg/m³ sensitive individuals may experience complaints. Above 1,000 µg/m³ action is required.
How We Measure VOC
We take indoor air samples — either via activated carbon tubes or TENAX adsorbents that draw in air over defined time periods. Analysis is carried out by GC-MS in the laboratory. For formaldehyde we use separate DNPH cartridges.
The result: a detailed breakdown of all detected individual substances with concentration, plus TVOC sum. This often allows the source to be identified.
A VOC indoor air measurement costs from €250. Result in 7–10 business days.
What You Can Do
Ventilate intensively: In the first weeks after a renovation, burst ventilation (3–4 times daily, 10–15 minutes) is the most effective measure. When moving into a new build, heat and ventilate for 2–4 weeks before moving in if possible.
Identify the source: If complaints do not subside after weeks, an indoor air measurement helps identify the specific source — and to act specifically rather than replacing everything.
Material selection: For future renovations: products with EMICODE EC1, Blue Angel, or natureplus certification off-gas considerably less.
VOC are incidentally a typical problem with new builds and renovations — quite different from the old-building pollutants PAH (→ PAH in Old Buildings) or asbestos. Independent renovation monitoring (→ Why an independent observer) helps to avoid such problems from the outset.
When You Should Get in Touch
You have persistent complaints after a renovation? It still smells intensely after weeks? You want to ensure indoor air quality before moving into a new build?
15-minute initial consultation, free of charge.