How soundproof is your home, and what can improve it?

Key rules

• Building age: A home built before 1981 had no national soundproofing standard, so expect weaker insulation.
• Windows first: For street noise, upgrade the windows before anything else.
• Curtains: Heavy curtains give little noise reduction.
• Footsteps: The best fix for noise from the flat above is a floating floor in that flat, not a ceiling below.
• Permission: Tell the community before works, and check whether new windows need authorisation.

Start with the building's age

The year the building got its permit tells you most about its sound insulation.

• Before 1981: Spain had no general national soundproofing standard for housing. Insulation was left to builders and local rules, so expect thin partitions and poor insulation.
• 1981 to 2009: A first national standard set minimum insulation between homes, limits on impact noise through floors, and facade requirements. It was revised in 1988. Results are better than before 1981 but often modest.
• From 2009: The current technical code sets performance values. Airborne insulation between homes should reach about 50 dB, and impact noise should be at most about 65 dB. Facade requirements depend on how noisy the area is.

Treat these figures as a guide. The permit date decides which rules applied, and the building's own documents are the best proof.

Check the home before you commit

Do these before buying or signing a long let. The checklist below lists them in order.

• Visit at rush hour, in the evening and at the weekend. Listen with the windows closed, then open.
• Look at the windows, and at neighbours such as bars, shops or lifts.
• Ask the seller or the community about noise complaints.
• Ask for the building's documentation (the libro del edificio) or the project's acoustic data.
• Look up the municipal noise map and any acoustic zone declaration for the street, from your town hall.

If you need a definite answer, hire an acoustic engineer to measure airborne, impact and facade insulation in the home. It typically costs a few hundred euros. The owner must agree to the measurement, so ask before you buy.

Street noise: start with the windows

Windows are the weakest point of the facade. In order of effect:

1. Acoustic windows. Laminated glass with panes of different thickness in an airtight frame typically cuts street noise by about 30 to 40 dB overall, depending on what you start with.
2. A second inner window. This can give similar or better results.
3. Sealing gaps and good seals. This gives a few dB and is cheap.
4. Insulated shutter boxes. Replace the roller-shutter boxes, which leak sound.
5. Acoustic trickle vents. Use them if you need ventilation with the window shut.

Heavy curtains do very little. Real results depend on your facade and the type of noise.

Acoustic windows cost more than standard double glazing. The price depends on the glass build-up, the frame, the size and the installation. Get quotes from several installers and compare the declared sound reduction value (Rw) in the product test data, not the sales claims.

Neighbour noise through walls and ceilings

• Walls (voices, TV): The best fix is a lined wall. A plasterboard layer on a frame, with mineral wool in the gap, can add roughly 10 dB or more. It takes 5 to 10 cm of room space.
• Noise from above: A suspended acoustic ceiling with mineral wool and resilient hangers helps. For footsteps, the best fix is a floating floor with an underlay in the upstairs flat. A ceiling below only partly helps.
• Finishing touches: Seal sockets and gaps. Results depend on how well the work is done and on sound travelling around the lining through other walls.

The works are messy but do not touch the structure.

Do you need permission?

Work inside your flat that leaves the structure, facade and shared parts alone, such as lining walls, a suspended ceiling or a floating floor, generally needs no community vote. You must still tell the community administrator or president, and you must not damage shared parts or harm other owners. Floor works may be limited by the community's rules on hours.

Replacing windows can need community authorisation if it changes how the facade looks. Work touching structure or shared walls can too. Community statutes may add rules, and you usually need a licence or notification from your town hall. Check both before you order.

Documents you need

• The building's documentation (libro del edificio) or the project's acoustic data, from the seller or the community, to see when it was built and what insulation it was designed to have.

• The municipal noise map and any acoustic zone declaration for the street, from your town hall.

• An in-place sound insulation measurement report from an acoustic engineer, if you want a definite result. The owner must agree to the measurement before you buy.

Check with the seller or your town hall which of these documents exist for the building.

Checklist

• Find out when the building got its permit. Homes built before 1981 had no national soundproofing standard, and the 2009 rules are the strictest.

• Check the window type and look for bars, shops or lifts next to the home.

• Start with the windows for street noise: ask several installers for quotes and compare the declared sound reduction value (Rw) in their test data.

• Seal gaps around windows and fit good seals, then ask about insulated shutter boxes.

• Tell the community administrator or president before you line walls or fit a ceiling, and ask whether new windows need community authorisation.

• Ask your town hall whether your works need a licence or a notification.

Frequently asked questions

Do I need community approval to line a party wall or fit a floating floor?

Usually no, if the work stays inside your flat and does not touch the structure, the facade or common elements. You still have to tell the community administrator or president before you start, and you must not damage common elements or other owners' homes. Check your community's rules on working hours and ask your town hall whether you need a licence or a notification.

Do I need community approval to replace my windows with acoustic ones?

Possibly, if the new windows change how the outside of the building looks. Facade changes can need the community's authorisation, and some community statutes add their own rules. Ask your administrator before ordering, and consider a second inner window, which leaves the facade as it is.

Is a ceiling below enough to stop noise from the flat above?

A suspended acoustic ceiling only partly helps with footstep and impact noise from above. The best fix is a floating floor with an underlay in the neighbour's flat, which you can only ask for, not do yourself. A ceiling with mineral wool and resilient hangers still cuts the airborne noise.

How do I compare quotes for acoustic windows?

Compare the declared sound reduction value (Rw) in each product's test data, not just the price. Installers quote per window or per square metre of opening, and the price rises with acoustic performance. Ask several installers for current quotes with the same window sizes.