SCHOMBURG GmbH & Co. KG Aquafinstrasse 2–8 D-32760 Detmold (Germany) phone + 49-5231- 953-00 fax + 49-5231- 953-108 email export@schomburg.de www.schomburg.com
Additional Technical Information no. 10
Layer thickness of the load distribution layer on LEWIS® dovetailed sheets LEWIS dovetailed sheets are rolled steel sheets formed with dovetails. They are used as formwork and reinforcement to support a concrete C20/25 (B25) casting compound or CT-C20/25-F4 (ZE20) cementbased screed on wooden or steel beam constructions. A very stable floor can be achieved with a construction height of only 50 mm. Alternative casting compounds must have corresponding compressive and flexural tensile strengths.
A further advantage associated with this is the reduction in the weight per unit area of the overall system. The following information is based on the strength classes and layer thicknesses of the cement-based screed above the profile specified in the general building inspectorate approval for LEWIS dovetailed sheets for the respective live loads.
The most important key data: • LEWIS dovetailed sheets are considered self-supporting floors • Building authority approval number Z-26.1-36 • Can be used unsupported up to a span of 1.50 m • Traffic loads up to 3.5 kN/m2: Concrete C20/25 or cement-based screed CT-C20/25-F4 with a casting thickness of 34 mm above the top flange (profile height 16 mm) = installation height of 50 mm • T raffic loads up to 5.0 kN/m2: Concrete C30/37 or cement-based screed CT-C30/35-F5 with a casting thickness of 39 mm and additional reinforcement (Q188) above the top flange (profile height 16 mm) = installation height of 55 mm
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Layer thickness of the load distribution layer on LEWIS® dovetailed sheets Load distribution layer
Structure per approval Z-26.1-36
ASO®-SEM2)
Strength class
CT-C20-F4 at 3.5 KN/m2 CT-C30-F5 at 5 KN/m2
CT-C40-F6
Compressive strength
>20 N/mm2 / >30 N/mm2
Flexural strength
>4 N/mm2 / >5 N/mm2
Traffic load 3.5 KN/m2 Minimum layer thickness 1)
34 mm
>40 N/mm2
>25 N/mm2
> 80 N/mm²
>6 N/mm2
>10 N/mm2
> 20 N/mm²
22 mm
20 mm
approx. 86 kg/m
approx. 35 kg/m
approx. 50 kg/m²
Material requirement for the load distribution layer (including profile filling)
approx. 82 kg/m2
approx. 35 kg/m2
approx. 5.5 kg/m² of the aforementioned binder + approx. 44.5 kg/m² quartz sand
39 mm
25 mm
Surface weight of the load distribution layer (including profile filling)
approx. 97 kg/m2
approx. 39 kg/m2
approx. 92 kg/m2
Can be covered with tiles and panels
after approx. 28 days
after approx. 3 days
after 1 day
Can be covered with vapour-tight flexible coverings
after at least 28 days (Dampness ≤ 2.0 CM%)
after at least 3 days (Dampness ≤ 2.0 CM%)
at least 1 day
YES 45 mm
YES 40 mm
NO
YES 20 mm
Suitable minimum pipe covering in conjunction with FB heating
2
) From profile top edge ) Can be covered with tiles after one day 3 ) Mix only complete containers! Mix ratio: 3 kg ASODUR-SG3/ASODUR-SG3-superfast + 25 kg quartz sand (grain size 0.06‒3.5 mm) 2
ASODUR®-SG3 ASODUR®-SG3-superfast 3)
Traffic load 5 KN/m2 Minimum layer thickness 1)
1
ASODUR®-LE
Note: Due to the reduced minimum layer thicknesses, particular attention must be paid to the climatic conditions found on site and the associated post-treatment, e.g. protection against damaging effects in accordance with DIN 18560/1 point 7.5, e.g. heat, draughts, etc. If post-treatment measures are not assessed, not correctly assessed or not correctly carried out, deformations and subsequent cracking may occur in the load distribution layer.
The rights of the buyer with regard to the quality of our materials are based on our terms and conditions of sale and delivery. Our technical advice team will be happy to advise you in the case of requirements that exceed the scope of the application described here. In order to be binding, a legally binding written confirmation is required. The product description does not release the user from a duty of care. Lay a test area in the event of uncertainty. This version becomes invalid in the event of a new version being issued. 2/2
RM/KK