Interior wall and ceiling paint buying guide
John, DIYer & IT developer, Brighton70 guides
What are wall and ceiling paints composed of
Wall and ceiling paints are composed of:
- binders or resins; à fiche traduite mais non publiée
- filler materials;
Binders and resins
Binders (acrylic, resin, etc.) give paint its adhesive quality; they then dry and harden on contact with the air.
They ensure the paint adheres to the painted surface, provide cohesion between contents and durability of the surface film.
Like binders, pigments are solid particles, however, pigments lend colour to the paint.
Pigments are not soluble but remain suspended in the paint.
Filler materials add bulk to the paint, they are usually used to increase coverage or to thicken the paint. Talcum powder, chalk, calcium carbonate (for weather resistance), diatomaceous earth (better matt effect), magnetic iron oxide (magnetic paint and improved sound insulation), barite sulphate (densification), etc.
Solvents are used to keep the binders in solution. These types of substance improve viscosity and liquify the paint. The paint’s drying time depends on the type of solvent used. They are mixed with paint (white spirit) and may be flammable.
Additives are compounds added to provide additional properties such as:
- increased penetration into the painted surface;
- better adhesion;
- a tighter appearance;
- anti-mould treatment.
- water-repellent qualities;
- fast drying (secative).
Additives may be in solid or liquid form.
What is a glycerol-based paint?
Glycerol, or oil-based, paint
Glycerol paints are oil-based paints that are diluted and cleaned using a solvent such as white spirit. They greatly increase the opacity of paint, lend it an attractive tight appearance, and are also more durable!
Glycerol paint is particularly suitable for humid rooms (such as bathrooms), and very busy rooms that get dirty quickly (e.g. the kitchen) and have to be washed. It is also the best type of paint if you want to paint over vinyl wallpaper due to its excellent coverage.
Glycerol paints tend to be replaced by acrylic paints and alkyd paints due to their high solvent content. Their application requires excellent ventilation in the workspace, during and after application, and respiratory protection must be used. Their drying time is long and their application (roller) requires more attention in order to avoid streaking.
What is an acrylic paint?
Acrylic or water-based paint
Acrylic paints are the most common water-based paints. It has the advantage of not producing an odour, making it the ideal paint to use throughout the entire interior of a house, while reducing environmental pollution.
Their advantages include a reduced amount of solvents with a short drying time - 30 minutes until touch dry. Moreover, composed of pigments, resin and water, they offer excellent coverage and can be applied easily on walls as well as on ceilings using brushes, rollers or a spray gun. However, water-based paints require careful surface preparation before application (intensive washing). Any stains on the surface should be removed, as they may reappear through the paint, especially if it is light in colour.
Acrylic paints cannot be applied over old oil-based paint, as they will not adhere to the surface, and may flake afterwards. It is therefore essential to sand the old paint, wash the wall with a pine resin or caustic soda based product, and sometimes apply an undercoat depending on the condition of the surface. There are many undercoats that can improve the bond between an old glycerol paint and acrylic paint.
The 'European Ecolabel' is awarded to the most environmentally friendly acrylic paints, which guarantees low VOC - Volatile Organic Compound - emissions. Water is used both to dilute these paints and to clean the tools used to apply them.
What is an alkyd paint?
Paints that offer the appearance of glycerol and acrylic
Alkyd paint is similar to acrylic paint in that it is mainly composed of water. In contrast, it contains more alkyd resin, which makes it much more durable than acrylic paint.
To understand the difference, it's necessary to compare the various paints in this family. Acrylic paints do not offer the same tight appearance as glycerol paints do. While they are more durable, they are also more toxic, requiring the use of solvents, and have a high rate of VOC (Volatile Organic Compound) emissions.
To compare these two types of paints, alkyd paints are better in terms of quality: low odour, water-based cleaning, short drying time (less than an hour), a high-quality tight appearance (which gives a lacquered or shiny effect) and increased durability. Because of their excellent durability, you can also use it to paint interior and even garage floors. Alkyd paints are also less toxic and have a lower level of VOC emissions.
There are several types of alkyd paint. The most common are emulsion alkyds, which offer a good compromise between glycerol and acrylic. However, they provide less coverage than their competitors. Alkyd-urethanes, mainly used for floors, due to their greater thickness.
Natural ecological paints and organic paints
Organic paints gained popularity and set themselves apart from other paints thanks to their very low petrochemical content, instead of using formulations of mineral or vegetable origin (linseed oil, lime, silicate, clay, castor oil, etc.) mixed with water. Their filler materials are also environmentally sound (marble powder, etc.) as well as their pigments (metal oxides, silica, etc.).
The term organic paint remains subjective, with manufacturers differing in their organic content from 100% natural down to 95%. Note that it is important to differentiate between organic paints and ecological paints, whether they are labelled or not, the latter emphasising low VOC emissions.
Although organic paints are less polluting (VOC levels lower than 5 g/l, with regulations allowing up to 30 g/l), they must also be applied using respiratory protection and ventilation in workspaces in which they are applied.
Natural paints are washable. They are UV resistant. On the other hand, the colour palette offered is less broad, and their drying time is long (minimum 6 hours, up to 12 hours).
Organic paints are labelled NF Environment, Ecolabel (represented by a flower), Natureplus (European label) or Natural Paint (awarded by Ecocert).
The finishes available for interior paints: gloss, matte and satin
Choosing the finish for your wall and ceiling entails both aesthetic and technical considerations. You can choose from three finishes: matte, gloss and satin.
Matte finish paint
Matte paints are the most fragile. They reflect light poorly, and so matte paints hide defects in the painted surface. It is an excellent choice for an old ceiling whose defects would be accentuated by reflected light. They are selected for rooms intended for relaxation such as bedrooms and are to be avoided on surfaces which receive high levels of traffic. They are somewhat difficult to wash, but they contain less VOCs than satin or gloss paints.
Satin finish paint
It is better to use satin paints to repaint wallsbecause they are more durable. A satin finish may be applied in all rooms around the house and has a silky appearance. It offers the perfect compromise between a gloss and matte appearance and is slightly shiny. Satin paint reflects the light well. It is easy to wash and provides good coverage.
Gloss finish paint
Gloss paints are even more durable and are recommended for door frames skirting boards and woodwork. With gloss paints, small rooms appear larger and dark rooms seem brighter. However, a gloss finish reveals defects and is relatively difficult to apply. The strong reflection offered by gloss paints lends intense brightness to walls and makes it the preferred paint where walls are new and flawless. It is very easy to wash.
The dangers associated with VOCs
Volatile Organic Compounds are chemicals incorporated into paints which are easily released into the air during application. More than 300 VOCs exist; they are composed ofcarbon, hydrogen, oxygen, sulphur etc. It is thought that these substances are toxic and carcinogenic. The most common are:
VOCs and health
In the absence of robust studies and as a precaution, it is advisable to avoid paints with high VOC emissions. The following effects may occur as a result of their use:
- irritation of the respiratory tract;
- irritation of the mucous membranes and skin;
- disturbed sleep;
- headaches and dizziness;
- a negative impact on reproductive capacity (glycol ethers).
Protect yourself from volatile organic compounds
A scoring system has been put in place to measure such emissions. The lowest VOC emitting paints are rated A +, up to C for the highest emissions. In all cases, it is advisable to ventilate workspaces well during and after the application of the paint and to wear a protective mask.
Note that for all paints, VOC emissions reach their peak 3 days after application. Paints are classed as"VOC free" when these substances make up less than 5 g/l of the final product.
The European VOC regulation (VOC Directive - 2007/2010) entered into force in January 2010 and permits:
- 30 g VOC/litre in wall paint;
- 250 g/litre for other paints.
VOC concentration must be indicated on paint and varnish tins.
What is an undercoat and what is it for?
Why use an undercoat
An undercoat is a specially designed paint intended to prepare finishings by standardizing the painted surface and reducing its porosity.
Even if its effects are not visible, the undercoat influences the rendering of the finish and its selection depends on the surface to be painted.
The different types of undercoat
Undercoats are chosen according to the surface to be painted and may be:
- universal for plaster, mortar, cement or wood;
- specific to drywall, specific treatment to protect the cardboard;
- hardener, to reinforce fragile or cracking surfaces;
- primer, to paint on surfaces that resist adhesion, such as plastic.
The advantage of using a special single-coat ceiling paint
Ceilings are surfaces with particular properties, they are unlikely to receive impacts, but tend to crack with age. Work at a height is inconvenient and tiring, a single-coat paint is a good solution which guarantees a beautiful finish, quickly!
Note that paints with a colour trace that disappears on drying are also available. These paints allow recently painted areas to be seen (unlike white paint on a white background), thereby ensuring all surfaces are covered.
Bear in mind that a matte finish erases defects on the ceiling while a gloss finish reflects light better and makes the room look bigger.
Choose a good quality interior paint
There’s paint and then there’s paint, and not all are made equal. Although you will find, cheap paint at a few euro per litre, you’ll have a spend a little more to get good quality paint.
When you triple the price per litre of the paint, you can imagine the difference. If you’re on the 4th coat of white and you still see the original paint underneath, you should buy another brand.
You’ll recognise a good quality paint by its:
- better adhesion to the painted surface;
- reduced VOC emissions;
- a high level of coverage;
- increased durability;
- a high-quality finish, be it matte, gloss or satin;
- a superior, tight appearance;
- a deeper, more pronounced colour;
- greater coverage per unit volume.
It is also essential to choose a paint that is specifically intended for the surface painted. The type of paint required will depend on the nature of the surface. Wall or ceiling, it's time to choose! Paint must also be selected according to the type of surface, whether it be concrete, plasterboard or vinyl wallpaper. Finally, the quality of the paint also depends on what the room is used for: do you need it washable, and resistant to moisture or would you rather a non-toxic and soothing matte finish?
How many coats and how many litres of paint to cover a wall or ceiling
Number of coats of paint
Most paints require two coats with time required for drying between coats. There are single-coat paints available that only require one application, as their name suggests. Be careful though, the more porous the surface the more coats you’ll need, even for single-coat paints.
The number of coats required is related to the level of coverage offered by the paint. If you are repainting a black wall with low coverage paint, you’d better buy your tins by the pallet!
Number of litres of paint
To estimate how many litres of paint you need, refer to the manufacturer's recommendations. The required litres per unit area is always given.
There is a wide range of paint tin sizes from 0.5 litres to 10 litres. You should buy the quantity you need first time, even if you need to over-estimate the amount. Remember that the price per litre is more advantageous in large containers and that the values given on tins of paint refer to optimal conditions (correctly prepared and lightly porous surface). Add 15% to the total volume calculated from the manufacturer's recommendation to be sure to have enough paint.
Recommendations for choosing the best wall and ceiling paint
In recent years, many unusual products have appeared. You can now easily find black (or white) board paints and magnetic paints that turn a smooth surface into a noticeboard. The range of colours has improved greatly, and you’ll find them all presented in a voluminous colour chart with evocative names... or not. It's up to you to detect the difference between Sahara and Sun Dune!
As for the finish, matte paints are a poor choice for surfaces that see constant use.
On the maintenance side, all paints are washable but to different degrees.
Also, watch for VOC emissions and do not forget that proper preparation is a necessary starting point for a result that meets your expectations. For best results, equip yourself with the tools of the trade (tray, roller, overalls, tarpaulin, etc.) pour when repainting your walls and ceilings.
In two words, what do I need to concentrate on?
John, DIYer & IT developer, Brighton 70 guides écrits
Lacking space, I have not got a permanent workshop and certain tools I dream about but are not part of my collection. Not to worry, I already know a lot about DIY and I have a high-tech profile that I hope will guide you in your decisions!