Preparing the room

Preparing the room

The room where the studio is built is square. Had electrical outlets, light switches, technical boxes where the electrical, alarms and communications cables pass, and two windows.
After removing all the school equipment, such as tables and chairs, all the technical boxes were dismantled and taken away. Cords were removed from the interior of the wall and the empty boxes have been filled with foam. Four boxes however, could not be removed because they are part of the emergency and communication circuits of the main building. Two of them were rebuilt facing the other side of the wall, since they are in the interior walls, and so, with access from the corridor and from the next room. The other two could not be turned due to the wall being outwardly. Two small doors were added to the sand wall so we can access the boxes in the future without having to demolish the wall.

Closing the windows with

sand bricks and cement.

The windows were closed with brick and cement.
On the other side of these windows is where the students gather together at class's break, and they make lots of noise. The exterior wall has 40 cm of thickness but the bricks only have 15 cm.

Filling the brick with sand.

The bricks were filled with sand to reinforce the isolation with the outside.
The sand acts as an absorbent once the sound energy has to bounce from one sand grain to another, thousands of times inside the brick, and this kills the energy. The sand also destroy the air cavity inside and the brick no longer resonate.

Mineral wool on the exterior side

of the closed window.

On the outside, a 5 cm layer of mineral wool was added before the finishing plate. This is another layer of protection against the sound energy. The sound that will be able to reach the bricks, will be so weak that the sand bricks will have no "work hard" to prevent the sound entering the room. The rest of the wall its a double wall with brick on the inside and reinforced concrete on the outside.

Metallic door´s frame
aligned with the
room's door.

After the room was empty, the sand wall position has been marked on the floor and aligned with the outer door.
The door is the weak point of the sand wall, with respect to acoustics.
The door frame was built first so that the wall could be perfectly integral with it. This, ultimately enhances the way the wall is related to the door and its expected insulation.

The project

This project is to build a sound proof room, with controlled acoustics to be used as a sound recording studio at ESAD College of Art and Design.
The main objective is to create a comfortable space where the school's noise do not interfere with the silence needed to record and edit sound.

The room has twenty seven square meters of free space. The inner wall is made with split brick filed with sand and it is floated. The floor is a structure made with wood and sand, with carpet on top, and floating foam at the bottom. The ceiling is completely supported by the sand wall, and do not touch the building. It is made of wood, plasterboard, M.A.D4, PKB2, and mineral wool. The door is made of solid wood and mineral wool, with eight centimeter of thickness.
The room also has an ventilation system made with silent motors and conducts, mounted two floors above, as far as possible.

One important aspect of this project is the weight of the structure. The sand wall and the sand floor are too heavy, and it is only possible to build this because it is located on the ground floor. There are others methods to insulate a room, with less mass, and more suitable to build on higher floors, so beware! If you intend to use this technic, always do all the math and ask an engineer for a professional opinion, or you can damage the building in an tragic way!

Next post: Prepering the room.