Noise, light and ventilation: how to check a flat at a viewing

Noise, light and ventilation are checked at a viewing with simple tests: silence in the bedroom with the windows closed and open, a visit at different times of day, a compass at the window and cross-ventilation. For noise there is an official benchmark: in the bedroom of a home the target level is 40 dB(A) by day and 30 dB(A) at night (RD 1367/2007, anexo II). These three qualities are what a renovation fixes worst, and they noticeably affect the resale price.

A check at a viewing is not a technical survey but a filter: it screens out flats where the problem can be seen and heard without instruments.

Why these three things matter more than finishes

A kitchen can be replaced, walls painted, wiring redone. A dark flat cannot be made bright, and a bar under the window cannot be moved. In Barcelona the difference is especially noticeable: dense development, the narrow streets of old districts, patios de luces (light wells), bar terraces. Two flats in the same building can differ in quality of life more than flats in different districts.

How to check noise

Noise is checked in three steps: the street, the flat, the time.

1. The street on the map. The Ajuntament de Barcelona publishes an interactive noise map with address search and data by time of day. These are modelled values for street facades, not a measurement in the flat, but they are convenient for comparing streets.
2. The flat with windows closed and open. Ask for two or three minutes of silence in each bedroom. Listen for the street, neighbours above and through the wall, the lift, a restaurant's ventilation, the courtyard: in patios de luces the sounds of kitchens and conversations carry well.
3. Another time. If the flat has passed the first screening, go back to the building on a Friday or Saturday evening and stand in the street for a while.

Benchmarks from the national noise regulation: for residential areas the target level in the street is 65 dB(A) by day and evening and 55 at night, and noise from an activity that penetrates an adjacent bedroom must not exceed 35 dB(A) by day and 25 at night (RD 1367/2007, anexo II and III). These are benchmarks, not a measurement: a specific dispute with a bar is settled by a specialist's measurement under the rules in force.

How to check light

Photos in listings are almost always taken with a wide-angle lens at the best time of day, so light is checked on site.

• Orientation. The phone compass at the living-room and bedroom windows. South and west sides get more sun, north gives even, diffuse light.
• What is opposite. A narrow street and a building of the same height opposite block the sun even on a high floor.
• Without lamps. Ask for all lighting to be switched off and see how much natural light there really is.
• Where the windows face. A window onto a light well gives little light and almost no view.
• Summer. A west-facing room can be very hot in August: are there shutters, awnings, air conditioning.

How to check ventilation

Poor ventilation means damp, mould and heavy air. The minimum is set by the Catalan habitability rules: a bathroom must be ventilated directly to the outside or through an extraction duct with mechanical ventilation, and a vertical duct also allows natural draught (Generalitat, criteria of Decret 141/2012).

At the viewing, look at:

• whether there are windows on different sides of the building and whether air moves when they are opened;
• whether the extractor in a windowless bathroom works and where it vents;
• whether the kitchen extractor vents to the outside;
• a musty smell in cupboards and corners, especially in a flat that has stood closed for a long time;
• dark patches in corners by windows, on the bathroom ceiling, behind furniture on an outside wall.

How to read figures from a phone: a worked example

Worked example, not a forecast. The buyer measures noise with a phone app. Such measurements are approximate and do not replace an acoustic engineer, but they show the order of magnitude.

The third row is the most dangerous: noise from a bar or restaurant travels through the floors and ventilation, and replacing windows does not remove it. Such a flat requires a discount that covers soundproofing, or a refusal. Soundproofing requirements in a renovation are described in the article on CTE DB-HR (the Spanish building code's noise protection document).

What a renovation fixes and what it does not

Usually solved with money: street noise with old windows (new windows), poor bathroom ventilation (an extractor), heat in a sunny room (shutters, awnings, air conditioning), damp from poor ventilation.

Usually not solved: darkness from a narrow street or windows onto a light well, noise from a bar or a main road if the bedrooms face only it, the lack of cross-ventilation in a flat with windows on one side. These drawbacks are built into the price from the start, and signs of damp are covered separately: see the article on damp problems.

When a check at a viewing does not work

A viewing does not replace a survey if sounds or stains already raise concern: then an acoustic engineer or a technical specialist is needed. It also does not work for a purchase at a distance if the video was shot by day with the lights on: ask for another video in the evening with the lamps off. How to organise such a check from abroad is described in the article on video inspection, and DNPI Capital takes the effect of defects found on price into account in a property valuation.