Key points
- Volatile organic compounds (VOCs) evaporate from paint during and after painting; the US EPA notes indoor levels are typically 2 to 5 times higher than outdoors.
- EU Directive 2004/42 caps VOCs for interior matt wall and ceiling paints at 30 g/L since 2010.
- Higher sheen means more durability and easier cleaning, but shows surface imperfections more.
- Ceilings and low-traffic walls: flat/matt. Busy corridors and rooms: eggshell or satin. Doors, trim and cabinets: semi-gloss or gloss.
Paint is the cheapest way to change how a home looks, but it's also one of the materials that most affects indoor air. This guide helps you choose the type and sheen by location, and understand the figures on the label.
1) Volatile organic compounds (VOCs): why they matter
VOCs are gases emitted from certain solids or liquids, including paints, varnishes and waxes containing organic solvents. The US Environmental Protection Agency (EPA) notes1:
- Indoor levels of many of these compounds average 2 to 5 times higher than outdoors.
- During some activities such as paint stripping with solvents, and for hours afterwards, levels may reach 1,000 times outdoor levels.
- Exposure can cause eye and throat irritation, headaches and nausea, and some are suspected or known carcinogens.
VOC limits in EU legislation
European Directive 2004/42/EC set maximum VOC contents for decorative paints; these examples are from Phase II values in force since 1 January 2010 (g/L of ready-to-use product)2:
| Product category | Water-based (WB) | Solvent-based (SB) |
|---|---|---|
| Interior matt walls and ceilings | 30 | 30 |
| Interior glossy walls and ceilings | 100 | 100 |
| Exterior walls of mineral substrate (cement, render) | 40 | 430 |
| Interior/exterior trim and cladding paints for wood and metal | 130 | 300 |
| Varnishes and woodstains | 130 | 400 |
| Primers | 30 | 350 |
| Two-pack reactive performance coatings for specific end uses such as floors | 140 | 500 |
Note the large gap between water-based and solvent-based in the exterior, wood and primer categories. These are EU figures cited for comparison; ask for the VOC value on your product.
2) Water-based or solvent-based (oil)?
| Type | Advantages | Notes |
|---|---|---|
| Water-based (acrylic/vinyl) | Less odour, usually lower VOC, dries faster, tools clean with water. | The most common choice for interior walls and ceilings. |
| Solvent-based (alkyd/oil) | Hard film and good levelling, abrasion-resistant. | Higher VOC and stronger odour; needs ventilation and solvents for cleaning; usually for wood and metal. |
| Two-pack epoxy | High chemical and mechanical resistance. | For floors and industrial environments; needs careful preparation. |
3) Sheen levels: which goes where?
The general rule: the higher the sheen, the more durable and easier to clean — and the more surface imperfections show. A summary of Benjamin Moore's recommendations3:
| Sheen | Where to use | Durability and look |
|---|---|---|
| Flat | Ceilings and walls in low-traffic areas. | Least durable and stains are hard to remove, but hides imperfections best. |
| Matte | Bedrooms, dining rooms, hallways, family rooms and bathrooms. | Better than flat and withstands frequent washing, with good hiding of imperfections. |
| Eggshell | High-traffic walls, living, dining and bedrooms. | Almost no shine, easier to clean and more durable than matte. |
| Pearl/Satin | High-traffic walls, trim, doors, cabinets. | Better stain resistance, but shows lap marks and paint flaws more. |
| Semi-gloss | Trim, doors, cabinets, kitchen cabinets. | Durable and easy to clean, highlights details. |
| High gloss | Doors, trim and cabinets in busy areas. | Very durable and stain-resistant but highlights flaws; use only on perfectly smooth surfaces. |
4) Primer: when do you need it?
- On new plaster, gypsum board and filler (evens out absorption and prevents shiny patches).
- When changing a lot from a dark to a light colour.
- On bare wood and metal (a dedicated primer for each).
- Over old oil paint if the new paint is water-based, per the manufacturer.
5) Paint is a system: surface and moisture, then primer, then colour
- Cause first: fix the moisture source before painting, and if efflorescence keeps appearing, delay painting4. See Paint problems and Damp walls.
- Surface: clean, dry and sound; cracks treated with a suitable filler. See Sealants.
- Primer: by surface (Section 4).
- Sheen by use and cleaning (Section 3), and VOC by ventilation (Section 1).
- Maintenance: keep some of the same colour and batch for touch-ups. See Paint a room yourself.
For outdoors: Exterior finishes.
6) Before buying
- Read the label: type (water/solvent), VOC, coverage (m²/L), drying and recoat time.
- Work out the quantity with the paint calculator, usually for two coats.
- Buy the full quantity from the same batch number to avoid colour differences.
- Ventilate well during and after painting and follow the label — the same advice the EPA gives to reduce exposure1.
- For a step-by-step job: the DIY room painting guide. For problems: paint problems.
Sources
The number next to a statement points to its source in this list. Sources back the general information; anything marked “practical advice” is editorial experience, not a quoted source. Anything that affects safety, structural design or electrical installations needs a licensed professional, and in Saudi Arabia the binding reference is the Saudi Building Code.
- 1Volatile Organic Compounds' Impact on Indoor Air Quality — U.S. Environmental Protection Agency (EPA)
- 2Directive 2004/42/EC — Annex II: VOC limit values for decorative paints and varnishes (Phase II from 1.1.2010) — legislation.gov.uk
- 3How to Choose a Paint Finish — Benjamin Moore
- 4How to Fix Efflorescence (white crystal deposits) — Sherwin-Williams