The roof structure

In any case, the roof is an outstanding part of the building, because regardless of the type of construction, a roof has some weak points, which are caused in particular by the massive load. The roof structure is therefore also multi-layered. So you have to pay special attention to the roof structure. You will then receive useful knowledge about roof construction.

The roof - a component subject to maximum stress

No other part of the building is exposed to such extreme loads as the house roof.

  • Also read - The verge on the roof
  • Also read - roof structure in detail
  • Also read - roof box - rounds off the roof and protects
  • UV radiation
  • warmth
  • cold
  • Water, snow, ice
  • Wind and air suction
  • mechanical stress due to ice precipitation (gel) but also rain
  • Pests (sponges, mold)
  • Vegetation (lichens, mosses)

Even more than the cellar is used for

Perhaps you are now thinking of the cellar, which is also heavily burdened. Nevertheless, the load on a roof is heavier. The effects in the basement are constant, at least in some areas, while on the roof there are always sudden changes in weather, temperature changes, etc. Show effects.

The roof structure in general

The structure of a modern roof is therefore extremely well thought out and also complex. Everything has to be perfectly coordinated. An assembly or material fault in just one roof layer has a negative impact on the entire roof structure. Basically, the roof structure always looks similar. The following is the roof extension from the outside to the inside.

  • Roof skin, also drainage and rain protection
  • Undercover, protection against slight leaks (rain or snow carried under the roof membrane by wind)
  • Layer of air
  • Counter battens
  • windproof layer
  • Rafters (or / and purlins)
  • Interior work

Different roof structures

Depending on the roof structure, thermal insulation and vapor diffusion (vapor barrier or vapor barrier) differ significantly in the roof structure. In the case of the roof construction of a sloping roof, a distinction is made between warm and cold roofs. The cold roof is, on the other hand, not ventilated from the rear.

Chronological applications cold and warm roof

For a long time, the ventilated cold roof was the standard for sloping roof surfaces. The warm roof has been used on flat roofs since the 1950s, but you probably know the disadvantages of this type of roof, which were not manageable for a long time.

Why warm roofs have been used for a short time

The warm roof tended to leak very quickly. In the case of sloping roofs in particular, the different thermal properties of different building materials that meet each other repeatedly led to major problems. In the meantime this can be managed with suitable modern building materials. That is why the more efficient warm roof is standard today.

Breathable and impermeable

The difference between warm and cold roofs is most evident in the roof structure. In the case of a cold roof, the cladding (roof or interior construction, for example plasterboard), vapor-permeable insulation, a vapor barrier, and then the rear-ventilated layer come from the inside to the outside. With a warm roof, the vapor barrier is installed after the interior work, followed by the thermal insulation.

Both types of roof have external ventilation!

However, the thermal roof is also ventilated in the area of the counter battens so that additional moisture can be transported away. However, this rear ventilation does not replace the other building ventilation required for a warm roof.

Warm and cold roofs always have particular weak points, even if the warm roof is much more efficient. Breakthroughs for chimneys or skylights or. Dormer windows represent such risk points at which thermal bridges can also quickly arise due to improper processing. Mold is then only a matter of time.

While warm roof constructions are mainly used for new buildings, the proportion is mixed for existing buildings. The older a roof, however, the more likely it is to have a cold roof structure.

Tips & Tricks The house journal provides you with various articles on all topics related to the roof. This also includes insulating the roof structure.