Buy paint: surface, finish and finish

1. Build a list of surfaces

Measure each wall or element separately and note the parts you want to deduct. Distinguish ceiling, walls and woodwork: they can request different products. Describe the condition of the support, the old coatings and the necessary repairs. A simple total in square meters does not tell whether the support is absorbent, smooth or degraded. Photograph the areas that ask question to ask for technical advice from the seller or manufacturer. Prepare your list before choosing a color in order to avoid the purchase of the pot before identifying the right system.

• Area by area noted.
• Identified media.
• Remedies identified.

2. Calculate with explicit assumptions

Indicative calculation: multiply the area by the number of coats, then divide by coverage in square metres per litre. Hypothetical example: 40 m², two coats and 10 m² per litre require 8 litres, before adjustments for site conditions. This does not guarantee actual consumption; the technical data sheet and surface condition remain decisive. Compare available pack sizes and the total purchase cost, not just price per litre. Ask what allowance suits your project rather than applying an arbitrary percentage.

• Consistency units.
• Layers and yield indicated.
• Comparative packaging.

3. Compare finish and preparation

Check the authorized use, finishing, cleaning conditions and preparation steps. A sub-layer or prior operation may change the cost and duration of the project. Note the times announced with their context: dry touch, delay before another layer and re-introduction do not always describe the same step. Test the shade according to the light of the room when suitable samples exist. Add abrasives, protections, tools and products necessary to compare two systems capable of treating the same surface under the same conditions.

• System adapted to support.
• Distinguished time and stages.
• Tools and preparation included.

4. Prepare application and storage

For the products concerned, the French labelling of emissions in indoor air presents classes from A+ to C. It informs on this criterion, without guaranteeing the absence of any precaution. Also read the warnings, protections, ventilation and temperatures prescribed in the notice. Organize the work site to avoid putting the part back into use on a simple drying impression. Keep reference, dye and lot number for a retouch or technical question. Follow the local instructions for collecting the remains and packaging; do not improvise a disposal in the pipes.

• Label and warnings read.
• Planned ventilation and planning.
• Reference and lot retained.

Fictional example · No merchant prices

The larger tin does not always give the cheaper basket

Fictional example: cover 32 m² with two coats of the same paint rated at 10 m² per litre per coat. The theoretical requirement is 32 × 2 ÷ 10 = 6.4 litres before allowances for the surface or waste. Three 2.5-litre tins at €29 provide 7.5 litres for €87. Two 5-litre tins at €49 provide 10 litres for €98. The larger size costs less per litre purchased, but the smaller tins save €11 here and leave less unused paint.

• Measure the area to paint; distinguish floor area from wall area.
• Confirm coats, any primer and coverage on your surface.
• Round up to tins actually sold, then allow a margin justified by the job.

Check the price per litre of each size