14.01.2016

Floor of the future: Finnish innovation cuts the cost of multi-storey wood construction

In the spring of 2104, A-Insinöörit and Metsä Wood began developing a new intermediate floor solution that would require no floating floor. Before that, no-one in Finland had built a wooden intermediate floor without also including a floating floor. The development project was a success, with the new intermediate floor design meeting key requirements for soundproofing and structural integrity. The new floor also enabled builders to utilize the same flooring materials as used in precast housing construction.

Because the new wooden intermediate floor requires no floating floor, the solution helps reduce construction costs in two ways: Builders have to deal with fewer layers of flooring materials, and more on-site work can be transferred off-site to building element manufacturers. When combined, these two benefits also improve construction productivity.

In fact, intermediate floors play an important role in the competitiveness of low-rise wood construction, largely because they bear the load of different building codes and regulations. Intermediate floors have to meet requirements for loadbearing capacity, bending and vibration, heat conductivity, and acoustic insulation. At the same time earlier studies suggested that building a wooden intermediate floor without a floating floor was impossible.

In Finland, intermediate floors in wooden apartment buildings have traditionally been built by installing floating floors and suspended ceilings alongside loadbearing timber frames. Even according to a recent international research report, an intermediate floor requires a floating floor to effectively dampen the noise caused by footsteps.

Metsä Wood’s Kerto-Ripa® LVL roof and floor solutions were the starting point for the new wooden intermediate floor. Previous research was used to evaluate the soundproofing properties of the new floor solution. A-Insinöörit also developed a computational model for determining how well wooden intermediate floors block out the sound of footsteps.

The model is parametric, and takes into account, among other things, flooring and concrete floor properties, drop ceiling design, mounting solutions, and possible stone wool insulation between load-bearing joists. According to the model, the new wood intermediate floor solution lives up to its promise, and provides an effective barrier against footstep noise. The test results were also validated empirically at VTT Technical Research Centre of Finland’s noise control and sound quality facilities.

A-Insinöörit is one of Finland’s leading experts in the construction industry, employing almost 600 professionals globally.

Metsä Wood (formerly 'Finnforest') is the wood products arm of Finnish pulp and paper group Metsäliitto.

Source: Sofia Virtanen, Tekniikkatalous.fi