Why is paint quality mostly about wall preparation?
Because paint copies the relief: it does not hide irregularities, it emphasises them, especially in raking light. In practice people say that two thirds of the result come from skim coat, sanding and primer, and the painting adds the rest. That is not an exact figure, only an order of magnitude.
That is why in a premium project the painting estimate and programme are calculated from the level of preparation, not from the number of coats. The same white on a wall with basic preparation and on one with fine preparation looks like two different products. Below we look at how walls are checked, how lime differs from acrylic, where an even dark colour comes from and how lacquered doors are made.
How are walls checked for flatness before painting?
With a two-metre straightedge and raking light. The straightedge is laid against the wall in several directions and the gap is read; in quality work the tolerance is usually set at around 2 mm per 2 m, but that value belongs in the contract or the finishes schedule, not in someone's memory. Then, in a darkened room, a powerful lamp is held close to the wall at a shallow angle: every bump and every sanding groove throws a shadow.
For plasterboard, European practice describes four levels of joint finishing, Q1 to Q4. The higher the level, the more passes and the thinner the continuous skim over the whole plane; low levels allow joints to show in raking light. Under glossy finishes, dark colours or a wall that takes raking light from a window, the highest level, Q4, is usually specified.
The order is levelling, skim coat, sanding with grit of roughly 180 to 240, dust removal, primer, an inspection under light and only then the finishing coats. A check before the primer costs less than one after the first coat of paint.
Lime paint or acrylic: which is more practical?
Acrylic is more practical day to day; lime is more beautiful on the right substrate. Acrylic paint forms a film, can be washed, goes on evenly and changes little over time. Lime paint (pintura a la cal in Spanish) is made from slaked lime: it is matt, breathes, has more depth of colour and lives on mineral substrates, that is, plaster, cement render and lime layers.
Lime is applied with a brush in a cross pattern, in 2 to 4 thin coats with drying between them, usually 12 to 24 hours. The living clouds on the surface are part of the intent, which is also why spot repairs show: you cannot touch up a small mark as you would with acrylic, you have to repaint the whole plane from corner to corner. Lime tolerates washing worse; for a kitchen or a child's room it is not the best choice, for a bedroom, hall or corridor it is fine.
On old lime walls in the Eixample, where the render breathes, acrylic traps moisture and lime works with it. Damp in old walls is discussed in a separate guide.
Why are deep dark colours hard to make even?
Dark pigment forgives nothing: a roller mark, a joint, a difference in sheen, a sanding scratch and dust in the coat are plain to see. A light colour scatters light and hides flaws; a dark one reads them.
What helps: preparation at Q4 or close to it, a tinted primer near the final colour, the whole batch of paint mixed in advance in a single container to avoid differences between tins, continuous application across a plane from corner to corner and one painter per room. Ideally the coats go on by spray or with a short-pile roller and are then laid off with a brush. The sheen is chosen as low as possible: a deep matt hides more than a satin.
Test the colour with a sample of at least 1 by 1 m directly on the wall, in different light and over two or three days. A dark colour in a room with a tall window and sun on the wall will look different from the card in the shop.
How are doors lacquered in colour?
In a workshop, in a booth, not on site. The doors are taken off or made in their final form, the pores are filled, sanded and given 3 to 5 coats of two-component polyurethane or acrylic enamel with sanding between coats. The whole cycle including drying usually takes 2 to 3 weeks, and the finish reaches full hardness a further 2 to 4 weeks after application.
For hidden doors, floor-to-ceiling doors and panels that should merge into the wall, the lacquer is made in the wall colour and painted from the same batch. The sheen of the doors is chosen separately: on a large plane gloss shows every irregularity, which is why a luxury interior more often uses semi-matt and a silky matt.
On site, doors are brushed only for touch-ups. Edges, tops and hinge recesses must be sealed already in the workshop, otherwise moisture moves the timber. Hidden doors themselves are covered in our guide to floor-to-ceiling doors.
When should painting happen: before or after joinery and lights go in?
The finishing coat goes on after the joinery is installed and the dusty trades are done, but before decorative items and rugs arrive. Primer and the first coat go earlier, while the last is applied to the finished plane so that the joints of panels, skirting and architraves are hidden under one layer.
In a complex flat the order is usually: preparation and primer, joinery installation, a second preparation of the joints, finishing of walls and ceilings, then lacquer on doors and furniture, and touch-ups after the lights are fitted. Between coats, temperature and humidity are watched: below 10 °C or above 70 % humidity, paint dries badly. In Barcelona in summer, a room that is too hot dries paint too fast, and it has no time to level.
One decision is worth making in advance: how many tins of each colour you keep. For each colour and sheen a reserve for touch-ups is kept, labelled with the room number. Two years later, the same shade from a new batch may differ.
How can BCN YARD help with painting in a premium project?
We suggest setting out in the estimate the level of wall preparation, the type of finish and the sheen for each room, with samples made on the site itself before the finishing begins. That gives a clear scope and comparable figures instead of a generic line for painting walls. We run projects in Russian and Spanish, with one person responsible; write to us and after the visit and survey we will prepare the estimate. As a guide, the Luxury level starts from 3,000 €/m² excluding VAT.
Frequently asked questions
Can lime paint go over a wall already painted with acrylic?
Not directly: lime does not hold on a film. The acrylic has to be removed down to the substrate or a special mineral primer applied to give it a key. Often it is simpler to re-skim the plane with a thin coat. Before deciding, test a small area: if the paint lifts in sheets, the substrate is not suitable.
How much does painting a flat cost at premium level?
The price depends on the level of preparation, not on litres of paint. A standalone figure per m² cannot honestly be given: in an estimate painting usually sits inside the general finishing, and the price is made up of skim coat, primer, coats, ceiling height and the complexity of the joints. The exact calculation arrives after the visit and survey; the site gives a guide by renovation level.
How does mineral paint differ from lime paint?
Lime paint is made of slaked lime and hardens by absorbing carbon dioxide. Silicate mineral paint is bound with potassium silicate and forms a stony bond with the substrate; it lasts longer and fades less, but works only on mineral bases. Both are matt and vapour-permeable, and both cope poorly with an acrylic base.