Renovation specialists on the roof

If the building roof becomes defective and moisture penetrates, roof renovation is usually the order of the day. Roof renovation specialists like LAMILUX can help.

Reading time: ca. 11:00 min.

Have the roof renovation done professionally

When exactly does a roof need to be renovated, who is the right renovation specialist for this and what are their tasks in roof renovation? First of all, the question of timing. The most common reasons, and therefore the time to renovate a roof, are damage caused by storms, a poor building structure, a poor state of construction or the age of the materials. When exactly, and how comprehensively, a roof renovation actually makes sense then depends on the specific individual case. If, for example, the roof sealant is already damaged and moisture penetrates the roof as a result, the perfect time for renovation has almost been missed.  

And that, of course, also costs money. Because the sooner damage is repaired, the cheaper the renovation will be. However, renovation is always worthwhile in the long term in terms of energy: If you want to reduce your heating costs or install a solar or photovoltaic system on the roof, a renovation can be a good opportunity to do so. For the success of this house project, however, the motto is first and foremost: Have the roof renovation done professionally.

All this is part of the roof renovation

The term “renovation” is, in a sense, the collective term for many different types of work. Such types include, for example:

  • Renovation and renewal of the roof truss  
  • Replacing or re-roofing the roof
  • Replacement or installation of insulation in accordance with EnEV or another heat insulation ordinance
  • Drainage renovation  
  • Renovation of the skylights and ventilation elements
  • Renewal of the waterproofing layer (for flat roofs)

Before you start a roof renovation, you should consult an energy advisor and, if the building measure is more extensive, an architect too. Make sure that they also have experience in renovation work. The same applies to the other companies that are then to work on your building roof.

Often the companies have references on their website that show how much and what they have already done in the field of roof renovation. But don't let that fool you: A website presence does not always show real experience and expertise.

LAMILUX, the manufacturer of rooflight domes, flat roof windows and continuous rooflights, for example, dedicates an entire section of its website to the renovation of skylights on flat roofs.  

Insulation and new roofing using the example of a steep roof

While renovation and renewal of the roof truss is usually only necessary for really old buildings, roof renovation usually involves the installation of insulation in accordance with the requirements of the German Building Energy Act (GEG), combined with new roofing if necessary. Whoever inserts insulation levels must work with sense and reason: The insulation levels must be constructed in such a way that the dew point shifts to the outside. Otherwise, moisture will accumulate in the insulation and damage the construction, for example in its load-bearing capacity or through pests and mould. Depending on the specific case, different insulation methods are used:

Insulation of the attic:

If the attic is not used as living space, attic insulation is sufficient. Insulation boards are laid on the top floor ceiling in the attic. The rooms below are insulated in this way at low cost. Work here should be as precise as possible to avoid cold bridges. A specialist planner assists with the implementation of this work. 

Inter-rafter insulation:

If the roof is only to be insulated, the insulation can be placed between the rafters. All insulation elements must be perfectly fitted into the spaces between the rafters. No crack should allow warm air to escape. Otherwise condensation could form here and cause roof damage. 

Over-rafter insulation:

If the roof has to be re-roofed at the same time, over-rafter insulation is the most effective type of insulation. The insulation material is placed between the rafters and the new roofing.  

Inter-rafter and under-rafter insulation combined: 

If the above-mentioned inter-rafter insulation is combined with under-rafter insulation, a second layer of insulation material is applied. However, the available space under the roof decreases. If this is to serve as living space in the future, this can be disadvantageous.

The flat roof is a different story. Read a separate article on how to renovate a flat roof.

Tip: Convert unused attic space into living space

If an extensive roof renovation is on the agenda, you can consider beforehand whether you want to convert previously unused roof space into living space. Such a building renovation often increases the property value considerably.   

A luxurious but worthwhile investment is offered when renovating the flat roof over an attic flat: Use the roof area as a roof terrace and thereby expand the living space in an uncomplicated way. But how do you get out onto the terrace? For this purpose, there are particularly elegant flat roof hatches, such as those from the LAMILUX Flat Roof Exit Comfort range. Depending on the model, the projecting glass element above a staircase opens like a recumbent balcony door, revealing the way to the sky. A rewarding story for investors and landlords: In some places, 60 percent of the total area of the roof terrace may be included in the rent. So the extension of the roof terrace quickly pays for itself.

The cost of a roof renovation

It is not possible to make a general statement about how expensive a roof renovation will be. This depends not only on the size of the roof, but also on the work that is to be carried out. In addition to the legal requirements, this also depends on the actual condition of the roof and what wishes and ideas you have regarding the renovation.These factors also play a role:

  • Pitch of roof
  • Roof shape, for example ridged roof, hipped roof, flat roof and so on
  • Number of chimneys, dormers, roof windows and roof terraces  
  • Skylights
  • Location and accessibility of the building project
  • Construction site equipment, for example the closure of parking spaces or entire streets
  • Necessary accident prevention measures (UVV), such as the closure of parking spaces or entire streets

You should therefore plan all aspects of the roof renovation with the professional you trust and make sure that their quotation describes everything in detail. Finally, a roof renovation also includes the costs for any scaffolding that may be necessary, and in the case of a roofing renewal, also the special tiles for the ridge and verge. If existing skylights or roof windows need to be renovated, this information must also be included in the quotation. It is also worthwhile to look for subsidies that specifically support roof renovation and energy optimisation.

Consider everything before a roof renovation

Thermal insulation through roof renovation

If more than ten percent of the roof is renewed during the roof renovation, the so-called 'de minimis limit' is reached. This meant that the regulations of the Energy Saving Ordinance, in short: EnEV, needed to be complied with. Since November 2020, the German Building Energy Act (GEG) has replaced the EnEV regulations. The GEG applies when the roof is re-roofed, but also when skylights or roof windows are replaced. If the house was built before 1984, insulation must therefore be retrofitted. This means that less heat is lost. The decisive factor here is the DIN 4108-2 standard, which regulates the minimum requirements for thermal insulation. The specialist company performing the work or the expert must document that the specifications of the standard for the so-called U-value, the heat transfer coefficients, are met.  

However, you should never regard the energy optimization of the roof in terms of thermal insulation as just a necessary evil. Because this measure not only benefits the environment and climate protection, but also the entire building and the building fabric. In a separate article, we have summarized everything about thermal insulation in buildings.

Provide more daylight when renovating the roof

Conclusion: Start the roof renovation in good time

Imagine a quiet evening, perhaps in autumn. Outside it's already a bit cooler, inside it's worth firing up the fireplace. The fire crackles and it becomes cosy and warm. If a storm with rain is approaching, you can listen to the knocking of the raindrops in peace. You are dry and safe within your own four walls. This all goes well as long as the storm does not pluck any tiles from the roof, for example because they are already dilapidated and somewhat loose on the rafters. Then it's time to scurry, put buckets and other containers in the attic to catch the water there. Maybe the raccoon living up there will help you. At the same time, you can try to pull in individual bricks while the storm and rain are still raging. No, that is no longer a pleasant idea.  

To ensure that you can look out of the window in all weathers with a relaxed and clear conscience in the future, you should think about roof renovation in good time. Let the professional take a look at your roof: Then you can continue to sit safely in the warm.

Outlook: Raise the steep roof to form a flat roof and thus create more living space

If you have a steep roof in need of renovation anyway, it is worth considering adding a flat roof to the top floor. Flat roofs are now brought to the construction site in modules and assembled. In order to bring daylight and fresh air into the building, skylights are again an option. The skylights from LAMILUX, for example, arrive at the construction site already completely pre-assembled and can be installed directly. For this purpose, they are installed in the first layer, in the first sealing level of the flat roof – this saves the installer measures such as emergency waterproofing or plank crowns and directly creates a tight building envelope.