Glossary

A

Abrasion
wear caused by rubbing or friction.
Abrasive paper
abrasive paper is commonly known as sandpaper. It consists of a sheet of paper covered with abrasive grit of differing sizes and used to sand or key materials. They are classified by numbers which correspond to the number of particles per cm²:
coarse and medium sandpaper (24, 40; 60, etc.) is used to remove finishes.
finer sandpaper (120 to 240) is used to smooth surfaces or create a key between coats.
ultra-fine sandpaper (400 to 800) is used to polish surfaces.
Acid-etch
to make a surface porous, especially concrete. Etching is done with an acid solution. This porosity is essential for the adhesion of certain paints.
Acrylic
a water-based type of resin. Today, these resins are used as binders in a huge variety of interior and exterior wood products and paints. They are capable of producing the same performance as solvent-based products. They have a milky appearance in the tin which disappears once dry. These resins have the advantage of drying quickly, have no unpleasant odour, have low VOC emissions, and tools can be rinsed in water.
Alkyd
a type of resin derived from acids in reaction with alcohols such as glycerol. Alkyd resins are generally used in solvent-based products, but can also be used in emulsion in water-based products. Alkyd resins provide a durable coat over any surface but have a much higher VOC content than acrylic resins.
Anhydrite screed: flowing liquid screed in which the cement has been replaced by calcium sulphate (anhydrite). It is essential to sand these self-levelling screeds before laying a floor covering or applying paint.
Antioxidants
substances contained in some types of wood (such as iroko, wenge, moabi). Antioxidants slow the drying of solvent-based products applied to such woods.
Autoclave (autoclaved wood): an autoclaved wood is a wood that has undergone deep treatment to protect it from biological attack (insects, fungi). However, this treatment does not protect wood from UV light or weather damage: a finish is required to provide this.

B

Binder
binder (or resin) plays a fundamental role in the formulation of a paint or wood product. The binder binds all the constituents of the paint together and produces a uniform film in paint and wood products. It also makes the film adhere to the substrate and determines its quality and resistance. The quality of the finish (paint or wood product) will depend on the quality and quantity of the binder.
Biocide
a treatment product or additive used to kill micro-organisms. Biocides eliminate insects (insecticides), fungicides (fungicides) or algae (algicides).
Bubbling
appearance of bubbles in a film of paint or varnish that are still visible when dry.

C

Capillary rising
humidity rising from the ground into the substrate via capillary action. Capillary rising can result in paint adhesion problems (particularly with exterior wall paints) and the development of saltpetre.
Chalking
when a paint or wood product film disintegrates into fine dust under the action of UV light.
Chalky
used to describe a deteriorated substrate which has formed a chalk-like powder. Chalky substrates must be primed or sanded before applying a finish.
Clean
to clean a surface using a cleaning product. This is often carried out before sanding to prevent the clogging up of abrasive paper.
Concrete
a mix of cement, sand, aggregates and water.
Covering power
ability of a paint to mask the substrate and to be opaque.
Cracks
linear openings (horizontal, vertical or oblique) affecting masonry. Cracks can vary in regularity and have a width of between 0.2 mm and 2 mm.
Crawling
when a layer of paint is unable to adhere to the substrate. The paint “draws up” into globules when applied, leaving the substrate visible in places.
Crazing
fine surface cracks on the substrate (concrete, parget, paints, etc.), resembling a spider’s web. Crazing does not adversely affect the solidity of the substrate and the coat of paint applied will not detach from it.
Cutting in
using a paintbrush to paint corners, moulding or any other surface that cannot be reached with a roller. Cutting in must be carried out just before applying paint with a roller. Any cutting in must not be allowed to dry before using the roller, otherwise lap marks will be visible. Cutting in is carried out with a special cutter brush.

D

Dewax
to remove layers of wax. This is done using a wax remover and grade 0 steel wool. Once the wax has been removed, it is essential to sand the wood to allow application of a film-forming product (such as a woodstain, varnish, paint, etc.).

F

Film
the dry layer deposited by a finishing product (woodstain, paint, varnish, etc.).
Film-forming
a product that creates a film on the surface of the substrate. Applies to all finishing products (paints, varnishes, woodstains, etc.) with the exception of oils and saturators which protect wood through saturation.
Finish
matt, satin or gloss. A finish describes the way in which light reflects off a given surface, in other words, the sheen level. A matt finish has no sheen at all and a satin finish has a light sheen.
Flaking
when the film of a paint or wood product detaches from the substrate in flakes. Flaking can be caused by:
– ageing of paint,
– water penetrating into wood via the gaps between planking, etc.,
– a poorly prepared substrate (grease, not keyed, waxed, oiled),
– a chalky substrate,
– a product applied to an inappropriate substrate,
– a product applied to a very cold wall,
– a paint or wood product film that freezes before fully dry.
Flow
ability of a paint to create a smooth finish and leave no surface defects.
Formaldehydes: chemical compounds emitted by certain products and materials. According to a study conducted by the French Indoor Air Quality Institute (OQAI), formaldehydes are among the most harmful components in the air inside our homes. Examples of sources of formaldehyde emissions: plywood, melamine panels, furniture, furnishing textiles, household cooking, cigarette smoke, etc.
Fungicide
product that prevents the development of mosses, lichens and fungi.

G

Galvanised metal
galvanised steel is coated with zinc to give it anticorrosion properties. To paint galvanised metal, it must be etched beforehand and then an undercoat applied, or an appropriate specialist product may be used.
Hairline crack
linear opening less than 0.2 mm wide (the thickness of a sheet of paper). A hairline crack is a superficial cosmetic defect that does not affect the structure of the wall and therefore requires no masonry work.

H

High-build
ability of a product to cover lumps and bumps and defects in the substrate by leaving a sufficiently thick coat of paint. During application, high-build products naturally deposit a thick layer of paint or wood paint. For example, solvent-based products are particularly high-build.
Honeycomb (roller): roller containing cavities and used to apply products in thick coats or create a textured finish when applying special coatings.

K

Keying
light sanding of the surface of a paint or wood product film. Keying creates porosity so that a new layer of product can adhere properly to the substrate. Keying can also be used to remove imperfections from the substrate or previous coat to ensure a perfect finish.

L

Lapping
a joining defect in a coating on surfaces painted at different times. Lapping marks may be due to the paint drying too quickly.
Lifting
softening of the dry film of a paint or wood product when applying a subsequent coat. Lifting can lead to the film detaching from the substrate.

M

Microporous
a film that is impermeable to liquid water, but allows water vapour to pass through it. Microporous finishes are used to protect wood while allowing it to breathe. All exterior wood products (paints and wood treatments) are microporous.
Miscible
two products that can be mixed together. For example, two colours of the same paint.

N

Non-fleecing (roller)
short-pile roller (4 to 6 mm). These rollers will give the finish applied a good flow.

O

Opacity
ability of a paint to mask the substrate.
Open pores
minuscule but relatively deep slits (a few mm long and less than 0.5 mm wide). Open pores are found in certain woods such as oak, chestnut, ash, meranti, etc. These open-grained woods often require special preparation in outdoor settings (undercoat or dilution of the first coat) and often cause peeling of woodstains.

P

Pigments
pigments can be of mineral or organic origin. Pigments are what give the product its colour and opacity. The most commonly used pigment is titanium dioxide (white pigment) and is included in paints to provide whiteness and opacity.
Porosity
characterises the absorbency of a material. An undercoat must be applied to highly porous materials. A special paint or special undercoat must be applied to non-porous materials.
Powdery
cf. chalky.
Powdery substrate
a degraded substrate with a non-uniform surface. It can also refer to a chalking surface. In most cases, a priming hardener is recommended for this type of substrate.
Primer (or sealer)
an initial coat that facilitates adhesion between the substrate and the finish.
Priming hardener
a highly liquid, usually transparent product used to fix powdery particles and harden surfaces.

R

Resin
see binder.
Roping
raised brush marks that are visible on the surface of paint or wood products after drying.

S

Sanding
returning a surface to its original condition using sandpaper. It is recommended to start sanding with a coarse sandpaper (between 40 and 60 grit), followed by smaller grit sandpapers to refine the first pass and create a smooth surface (80 then 120 for a wooden floor, 120 then 240 for woodwork or furniture).
Screed
layer of mortar or concrete (may be reinforced) poured onto flooring. The screed is a thin layer of material poured onto an existing structure to create a level surface. It may be used as acoustic or thermal insulation.
Sedimentation
accumulation of certain components in the product at the bottom of the paint or wood product tin. Sedimentation has occurred when these “lumps” cannot be mixed back in. It usually happens with very old paints or wood products.
Separation
occurs when the heaviest components of a product drop to the bottom of the tin. Separation often appears as liquid on the surface of the product, or unevenness of colour. In this case, before applying the paint, the product must be stirred well inside the tin using a wide paint stick. This mixes the paint evenly again.
Sharp edges
the outside corners of a plank of wood.
Smoothing compound
cement finishing coating laid on a screed or slabbing to smooth it out. Smoothing compounds are not very porous and often require treatment before painting (sanding or etching with hydrochloric acid).
Solids content
the dry matter contained in a paint or wood product after evaporation of the solvent or water.
Solvent-based
paint or wood product diluted with white spirit.
Solvents
solvents are used to adjust the viscosity (consistency) of paint. Once applied, they evaporate while the paint film hardens. There are two main types of solvent: water and white spirit.
Stippled
a textured pattern left in paint by a roller. The shorter the roller pile, the finer the texture. A short-pile roller deposits less paint than a long-pile roller.
Strip
to remove a finish (paint, woodstain, varnish, etc.) using a stripper. NB: two-component type finishing products cannot be removed with a stripper.

T

Tannin
substances contained in some types of wood such as oak and chestnut. Tannins rise in contact with water and form purplish, yellow or brown stains. High-tannin woods are often steam-dried to eliminate these tannins. An undercoat is frequently recommended before applying a paint or wood product to a high-tannin wood that has not been steam-dried.
Teflon®
a paint or wood product additive used to ensure better waterproofing and better stain resistance. Teflon® is a registered trademark of The Chemours Company FC, LLC used under licence by Groupe V33 SA.
Timber-boring
used to describe insects that feed on wood.

U

Ultraviolet (UV)
the part of sunlight that causes ageing of exterior finishes and deterioration of wood (greying).

V

VOC
volatile organic compound. Products with a white spirit base contain significant amounts of VOCs. VOC levels are indicated on the packaging of each paint, woodstain, varnish, etc.

W

Warming
the action of a wood getting darker (looking similar to wet wood) when an oil or solvent-based product is applied.
Wash
to deeply clean a substrate before applying a finish. A soda-based cleaner should be used, followed by thorough rinsing. Any cleaner residue can prevent adhesion of a paint or wood product.
Washability:
ability of a paint film to resist cleaning and not to get thinner with each subsequent washing.
Water-based
paint or wood product diluted with water.
Waterproof
a paint or wood product that prevents water from penetrating inside porous materials. This protects the material from water and staining.
Water-repellent
a paint or wood product that has no affinity with water and repels it.
Wet-edge time
length of time during which two adjoining applications of paint or wood product can be brushed into each other without leaving lapping marks.
Wide crack
crack which is greater than 2 mm wide. It must be scraped out and refilled before paint is applied.
Wood grain
alternating regions of soft and hard grain in wood. Wood products must always be applied in the direction of the grain.
Wood stripping
operation to get rid of worm-eaten wood on the surface of a structure and expose the wood below that is still healthy. It is used to identify areas that need to be consolidated or replaced. Stripping allows any products applied to directly penetrate the healthy part of the wood and not the worm-eaten parts.
Wrinkling
a paint film defect creating ridges and furrows. This phenomenon usually occurs when a coat of paint or wood product is applied to a first coat that has not fully dried.

Top of page
mi-terraza-a-prueba-del-tiempo