House on a main road? How to get genuine sound insulation

Many clients come to us after fitting double glazing elsewhere and finding the noise barely changed. The cause is usually one of three things, and all three are fixable.

Cause one: symmetric glass thickness

If the glazing unit is made of two panes of the same thickness — 4 mm and 4 mm, say — both panes vibrate at roughly the same frequency, producing resonance, and sound passes between them easily. The fix is an asymmetric build-up such as 6 mm + cavity + 4 mm. The difference in thickness breaks the shared frequency and measurably reduces transmission.

Cause two: a weak seal

Sound passes through the smallest air gap. A window with a single gasket or a brush seal, or a single-point lock that does not compress the sash evenly onto the frame, will leak sound around the edges no matter how good the glass is. The fix is two perimeter gaskets and multi-point locking that compresses the sash at three points minimum.

Cause three: an untreated perimeter

Even with an excellent window, if the gap between the frame and the wall is packed with plaster or left open, sound simply travels around it. The remedy is insulating foam filling the gap completely, a compression tape, and silicone on both faces.

What does "35 dB" actually mean?

The decibel is a logarithmic scale, so every 10 dB of reduction is perceived as roughly halving the sound. A 35 dB reduction turns a street at 70 dB (moderate traffic) into 35 dB inside the room — the level of a quiet bedroom. That is not absolute silence, but it does mean you stop hearing the cars.

Practical advice before you buy

• Identify the rooms that genuinely bother you — usually bedrooms and the majlis facing the road.
• You do not need to insulate the whole house to the highest spec. Spend on the noisy elevation and save on the internal ones.
• Ask for the glazing build-up in numbers in the quotation; do not accept "double" alone.
• Ask how many gaskets and how many locking points.

Want to try before deciding? Send "عزل" on WhatsApp — we will bring a profile and glazing sample to your home so you can see and handle it before committing to anything.