System Description
The requirements for interior eavestroughs are set out in DIN 1986 -drainage systems for buildings and properties. If interior drainage is unavoidable, the following rules should be followed without fail:
- At least twice as many run-offs than calculated are needed
- Gutter measurement must be done professionally
- Funnel-shaped, double intake feeds and ball protection
- On flat roofs, at least 30 cm distance should be kept from the insulation underneath to enable cross-ventilation .
- Distance between eavestrough and overflow gutter ≥ 20 mm
- Note expansion spacing
- Plan for steep gutter slopes (≥ 5 mm/m)
- Due to the danger of icing, avoid exterior drain-off if at all possible
- Provide thermostatically controlled gutter heating and snow guard system
- Conclusion of maintenance agreements
Dimensioning
- Roof drainage systems must be calculated hydraulically for sufficient dimension
- Valid DIN standards and regulations should be followed at all times:
DIN EN 12 056-3
Gravity drainage systems inside buildings, Part 3 - roof drainage, design and dimensioning
DIN 1986-100
Drainage systems for buildings and properties, Part 100 - Additional stipulations for DIN EN 752 and
DIN EN 12 056
Technical information from the ZVSHK. Dimensioning of bracket-mounted and interior eavestroughs
Compared to the all-inclusive gutter calculation, which was applicable up until now, as of July 2001, bracket-mounted and interior roof drainage systems must be dimensioned for sufficient sizing by means of an hydraulic calculation.
Since overloading an interior eavestrough can lead to a great deal of structural roof damage, an interior roof drainage system is measured for a statistical century of rain. In accordance with DIN 1986-100, this amounts to the local five minutes of rainfall which must be expected once in a century. The calculated rainfall intensity to be measured can be requested from the local authorities or alternatively from the German Weather Office.
Further variables are set out in the applicable DIN standards and in the ZVSHK technical handbook entitled "Dimensioning of bracket- mounted and interior eavestroughs".
Overflow gutter
- An overflow gutter is essential.
- Sealed overflow gutter
- Overflow gutter made of RHEINZINK
As a rule, interior roof drainage must be equipped with an overflow gutter. Overflow gutters can be laminated or made of metal. Even before the sheet metal work begins, they will allow rainwater to drain and provide a high degree of protection against backups. The distance between the eavestrough and the overflow eavestrough should be at least 20 mm. Every overflow eavestrough is equipped with its own drain-offs in order to ensure that possible water penetration can be diverted. Connection to the roof construction is to be carried out professionally so that no water can penetrate into the roof construction even during backups.
Expansion elements
- Expansion elements are to be installed based on standard size.
The following maximum dilation-free lengths apply in order to guarantee thermal expansion of interior RHEINZINK-gutters due to changes in temperature:
| nominal sizes |
Maximum distance of expansion elements |
|
= 500 |
12.0 m |
| > 500 |
9.0 m |
| box-shaped |
(general) 6.0 m |
Table: Installation distance of expansion elements
Half of the expansion-free value is to be kept for corners and ends, ie, fixed points in the gutter.
Handcrafted sliding joints made of RHEINZINK-strip expansion elements are particularly suitable to accommodate expansion in interior eavestroughs.
Longitudinal slope
- A minimum slope of 5mm/m must be provided
Interior eavestroughs should be installed with a minimum slope of 5 mm/m, in order to avoid a high degree of soiling and to prevent inadequate maintenance.
Gutter heating
It is recommended that an interior eavestrough be fitted with a gutter heater to avoid icing
