Preliminary statics

deflection w = l / 450 for floors in residential
developments, commercial developments and flat
roofs with a pitch of up to 5°

  • imposed load  qN+ surcharge qA
  • span l
  • element dead load accounted for in diagrams

Statics of roof

The adjacent tables show which element height h gives a span I. All roof systems shown fulfil the requirements for load-bearing capacity and serviceability.

deflection w (qd) = l / 350
• qd = (1 + kdef) ∙ (gk + ѱ1 ∙ qk)
• creep coefficient kdef = 0.6
• permanent load gk = g + qA
• dead weight of element g (data shown in tables for h = 200 mm)
• load roof structure qA
• imposed load qk = μ ∙ sK
• coefficient of roof shape μ = 0.8
• snow load sK = 1 kN/m2, ѱ1 = 0.5
• snow load sK = 3 kN/m2, ѱ1 = 0.75

1 layer of vegetation
2 drainage
3 polymer bitumen membrane 2nd layer
4 polymer bitumen membrane 1st layer
5 thermal insulation
6 vapour barrier

I LIGNATUR surface element (LFE)
II LFE with acoustics

Statics of floor

The adjacent tables show which element height h gives a span I. All floor systems shown fulfil the requirements for load-bearing capacity, serviceability and proof of vibration.

deflection w (qd) = l / 350

  • qd = (1 + kdef) ∙ (gk + ѱ1 ∙ qk)
  • creep coefficient kdef = 0.6
  • permanent load gk = g + qA
  • dead load incl. fill g (data in tables for h = 200 mm)
  • load of floor construction qA
  • imposed load qk = qN
  • housing qN = 2 kN/m2, ѱ1 = 0.5
  • education qN = 3 kN/m2, ѱ1 = 0.7


1. natural frequency f1 (gk + 0.3 ∙ qk) ≥ 8.0 Hz or 8.0 Hz > f1 (gk + 0.3 ∙ qk) ≥ 5.1 Hz
vibration acceleration a (gk + 0.3 ∙ qk) ≤ 0.2 m/s2
deflection w (F = 1 kN) ≤ 1.15 mm

1 parquet flooring
2 Fermacell screed element 25 mm
3 cement screed 50 mm
4 wood fibre footfall sound insulation 20 mm
5 mineral fibre footfall sound insulation 40 mm
6 Fermacell honeycomb fill 30 mm
7 bonded chippings 60 mm
8 bonded chippings 80 mm

I LIGNATUR box element (LKE)
II LIGNATUR surface element (LFE)
III LFE with fill 50kg/m2
IV LFE with fill 100kg/m2
V LFE silence12
VI LFE silence12 with acoustics