Delhaize – Kattendijkdok

In some multi-functional buildings, supermarkets are located under an apartment block which, if not isolated, may cause serious noise nuisance for the occupants. In particular, the rolling noise of pallet trucks is clearly audible as it is easily transmitted via the floor and as most of the loading and unloading activities are planned early in the morning or late in the evening, when background noise levels are very low, this is obviously of particular concern when designing the building. The main strategy of acousticians and architects to prevent this kind of noise nuisance is to decouple the entire floor of the supermarket and unloading areas by using a continuous mat isolation solution.

For the Delhaize project about 3000m² of floor have been decoupled by using a resilient recycled rubber mat with a wavy surface (CDM-MAT). In critical zones like the unloading area the applied mat solution was adapted to provide extra acoustic isolation. A floating reinforced concrete floor was then installed on top of the mat. Lateral decoupling of the loadbearing walls, columns, and services running through the floor was achieved by using CDM-PERIMETER strips which were meticulously installed to avoid all possible bridging.

CDM specifically developed for rolling noise isolation applications a full range of wavy surface mats (CDM-MAT), based on DLv,rn index. This new concept is used in France and based on an extended frequency range of 50 to 500 Hz, for better evaluation of the low frequency response and performance. The CDM-MAT has a profiled underside thereby minimizing contact points across the floor and reducing the structure-borne noise transmission to the supporting structure of the building whilst still providing a low resonance frequency for the floor system. The high density of the chosen CDM-MAT means a long-term warranty of the physical and acoustic performance of the system can be provided as the effects of creep are of no importance. Low density resilient mats are known to suffer from creep leading to reductions in elasticity and noise isolation performance in the long term.

Myriad by Sana Hotels

Located at Parque das Nações, a leisure, commercial and residential new district in Lisbon, the 5 stars hotel MYRIAD BY SANA HOTELS was executed in 2 concrete structure parts and glass surfaces with 142m height. The building is connect to the existing Vasco da Gama Tower, a metal structure tower inaugurated in 1998 during the universal exposition in Lisbon, EXPO 98, an emblematic structure during the exposition but also actually a national icon.

To isolate the technical rooms at 2nd, 21st and 23rd plants, several CDM-MONT-100 concrete slabs 100 mm thick with a natural frequency < 8 Hz were installed.

Besides this application, all concrete floor in the hotel were isolated with underscreed solution CDM-MTC-4,5.

A Jacuzzi and a swimming pool  located in the 22nd plant were also acoustically isolated with special CDM-POOL system.

Installation of CDM-MONT boxes and reinforcement bars

Installation of CDM-MAT

Installation of CDM-POOL

Ebury Square

Ebury Square is a high end residential development in Chelsea. There are two new buildings, one of which is built directly on top of the cut-and-cover tunnel of the Circle and District lines in between Sloane Square and Victoria.

The vibration levels on site are very noticeable and to limit the structure-borne noise levels both buildings were isolated on 3.2Hz CDM-CHR-BOX pre-compressed spring boxes. In total 341 spring boxes were designed, manufactured, supplied and installed by CDM. All springs went through a rigorous testing and quality regime to the satisfaction of all parties.


Barco, a significant leader in the market of projectors, is building a completely new headquarter complex at Kennedy Park in Kortrijk with a total area of 60000m². The architects Jaspers-Eyers designed a very strong modern building; the vast circular concept intended to echo dynamics, compactness and innovation. The main building houses a training room, conference facilities and restaurant. In addition several rectangular office blocks are also being built to provide space for a total of approximately 1500 employees.

On the first floor of the circular main building is a large meeting room, for which the acoustic consultant specified CDM-FLOAT a high-quality acoustic floating floor system. The CDM-FLOAT is a modular system which is pre-assembled at the CDM factory. It comprises high performance isolation pads and an absorption layer bonded to a lost formwork panel onto which reinforced concrete is then installed. The same system was also used for various machine rooms housing HVAC units on the upper floors.

One of the adjacent buildings houses a test facility which examines the effect of induced vibrations on new products. In order to sufficiently isolate vibration from the rest of the building two concrete inertia bases were installed in the basement on to which the test equipment was mounted. Both inertia bases were installed on flexible steel springs, with a resonance frequency of 2.5 Hz, and elastic lateral buffer pads were inserted, by means of special air cushions, in order to limit horizontal movements.

CDM-FLOAT - concrete floating floor

concrete inertia base

NYU Abu Dhabi

New York University is building a new campus in Abu Dhabi on Saddiyat Island. The new campus has 117,000m² of Academic
Space, 142,000m² of housing for students and staff, 34,000m² of car parking and 8,200m² of specialist research areas.

One of the buildings on the campus is the Arts building which contains a state-of-the-art Auditorium, a Black Box Theatre and a Recital Hall. The Acoustic Consultant specified that all three of these performance spaces should have 150mm thick concrete floating floors on a 100mm void with a system natural frequency of <10Hz. The CDM-QDECK system was used which was designed to take perimeter wall loads of over 100kN/m.


Sedmikraska residential building was commissioned by the Daramis Group in the 9th district of Prague located directly over the twin tunnels of the Metro Line B. Measurements confirmed that vibration isolation of the building was required; although this was already expected because all other new buildings in the area had been isolated or, if not, were having noise problems.

CDM-SEB elastomer bearings, with a design load of approximately 6 MPa, were installed at the top of pillars and walls just below the ground floor slab. Elevator shafts were isolated from every floor slab to provide resilient load transfer between the isolated and non-isolated structure.

CDM-SEB system on top of a column

CDM-SEB deflection measurement

80 Marine Parade Drive

Reported by the Acoustician, the frequency response of the existing gym-floating floor was measured in a heel drop test. The measured response frequency of the floor was broadly in a range centred at about 15 Hz.

CDM-CA Ltd designed, supplied and installed a retrofit floating floor solution. With use of past CDM lab test data, and by performing in-situ mock-up trials consisting of various material and cross-sectional designs, 3-different floor build-ups were tested, 1-remained as being 100% successful, resulting in no perceived vibration or audible noise in the tenant’s suite.

The CDM-FLOAT solution eliminated the 43 dBA measurements previously recorded, using a specific floor buildup not involving a concrete floating slab, to achieve a sound level of less than 35 dBA.

Finished gym floor

Nouvel Hopital d’Orléans (helipads)

Nouvel Hôpital d’Orléans is a new hospital in Orléans which is South West of Paris in the middle of France.

There are 2 helipads on the roof of the hospital which needed to be isolated from the hospital to protect patients and staff from the noise and to minimise vibration to sensitive hospital equipment. CDM-SEB 8Hz bearings were used to isolate the roof area where the helicopters pads are located directly above the accident and emergency department.

Gresham Palace

The 100 year old art nouveau Gresham Palace is Four Seasons’ first hotel in Hungary and is located opposite the historic 150 year old Chain Bridge and Royal Palace.

During recent renovations a fitness suite was located directly above some of the Palace’s most exclusive rooms and there was concern that noise generated from activities in this new suite would cause a problem to guests accommodated below.

A CDM-LAT floating floor was selected because it has a proven success rate in many similar projects across Europe and because the system is easy to install. The CDM-LAT floor was designed to provide maximum isolation and minimum deflection.

CDM-LAT system during installation

The completed fitness room

PS/IS-314 Q

PS/IS-314 Q is a 115,000 SF elementary and intermediate school in Jamaica, Queens NY. The school accommodates 830 students in grades PK through 8. Located at the corner of 164th Street and Hillside Avenue, the L-shaped building encloses and defines a significant public open space that will serve the recreational needs of the school and community.

The school is organized into two main components. A four story Academic Wing will be constructed along the west edge of the site, encompassing instructional spaces, offices, Cafeteria and Library. A three story Public Assembly Wing will be located at the northeast corner of 164th Street and Hillside Avenue, comprising the Gymnasium and multi-use “Gymatorium”. A two story glass-enclosed Lobby/Gallery joins these two wings to provide for the school’s main entrance and connect the major internal public spaces to facilitate their use by the community after school hours.

The building is located at < 15 ft from Subway line F on Hillside Avenue between Jamaica 179th and 169th Street Stations. In order to safeguard education N&V comfort levels, it was decided to base-isolate the building entirely with intervention below raft foundation.