Roof terrace on roofing felt: how to proceed?

A flat roof is very often sealed with roofing felt. What to look out for, if you want to build a roof terrace on it, and which points are particularly important, learn in this post.

Noteworthy points

  • Statics of the bituminous badger
  • Waterproofness of the roof terrace
  • Pressure bearing load of bituminous roofing
  • possible root protection

Statics of the bituminous badger

Of course, the statics of a flat roof must allow sufficient load capacity for a roof terrace. Depending on the type and construction of the roof terrace, high surface weights may occur, which must be taken into account in planning.

This is especially true for green roof terraces, which often generate particularly high surface loads, which are often underestimated. But already quite simple substructures can represent a high Gewichitsbelastung.

Waterproofness of the roof terrace

Also, the roof terrace must be waterproof, so there is no standing water on the bituminous membrane and no puddling. Technically, this is often difficult and complicated - for this reason, roof terraces together with the appropriate seal and insulation should always be planned by a specialist.

Pressure bearing load of bituminous roofing

Above all, the bearing load of the wooden substructure plays an important role in a roof terrace made of wood.

Here a corresponding protection must be attached so that the substructure does not damage the bituminous roof (pressure load). In addition, the contact pressure of the substructure should be distributed as evenly as possible. This can be done by:

  • a several centimeters thick gravel bed
  • a pedestal bearing construction
  • a bearing surface of the beams protected by building protection mats

Pedestal bearings also allow height adjustment of the substructure and a slight compensation of minor unevenness on the roof. In terms of the spaces between the roof, substructure and terrace, however, you have to be very careful. Again, the danger of standing water (which can not drain properly) could be given.

Possible root penetration protection

In the case of roof terraces on which plants are planted, attention must also be paid to appropriate root protection. Here, the same rules apply to a proper construction as in an extensive roof greening.

Tips & Tricks

A roof terrace is always subject to approval. For this reason, it is best to leave the entire planning to an experienced specialist (for example, a roofer). Tightness of the roof terrace should definitely be top priority in the planning.

Video Board: BASE PLATE WATERPROOFING – against negative water pressure with load on top