If the old roof needs renewal after a few decades, it makes sense to think about roof insulation. What can cost a roof renovation including roof insulation, and what factors you can expect, you will learn in this post.
For our model example, we have subjected a 10 x 12 m large detached house to a roof renovation. 32 m rafters had to be replaced because they were damaged, the rest was intact. The roof was covered with concrete blocks and provided with a roof insulation. The roof area was at our house 180 m².
|Work step||Costs total|
|Renew rafters||322 EUR|
|Roof insulation (roof insulation)||15.618 EUR|
|Covering cpl. Renewing, roof formwork and vapor barrier||2.980 EUR|
|Roofing with concrete roof tiles||5.782 EUR|
|Total basic costs||24.702 EUR|
The above sample is just a single example. The prices quoted may vary significantly depending on the circumstances in your home and contracting company. Many houses often require other or additional work steps.
For reasons of clarity, we have also disregarded the following costs:
- Rooftop scaffolding
- Demolition of the old roof
- Eaves design
- Installation of roof drainage
- Special work such as roof penetrations, chimney seals, roof exits, etc.
- Smaller adaptation work in individual areas
These costs may therefore be additional towards you.
When designing a roof, there are many very different options. In many cases, the overall cost can be significantly reduced by cheaper roof construction, but each type of roof structure has its own advantages and disadvantages.
Renewing parts of the roof truss and rafters
Roof rafters and all parts of the trusses must be checked to see if they are still intact before the roof is renewed. If necessary, individual parts of the roof truss must be replaced. In some cases, it may also be necessary to rebuild the entire roof structure. When replacing individual parts is usually calculated by meters.
The costs for a complete roof truss can be found in our corresponding special article. For the parts of the roof truss, you can usually calculate between 8 - 10 EUR per m (not per square meter, but per running meter!) (Including installation).
In particular when installing a roof insulation, but also with a new cover, the battens must be completely or partially renewed in order to be adapted to the thermal insulation and the roofing. The distance between the slats depends on the type of cover, and the price per m² is accordingly different. You can base your prices on the following types of laths:
|Type of lathing||Cost per m² of roof surface|
|Basic lathing||approx. 3 - 6 EUR per m² area|
|Counter battens, non-load bearing||approx. 3 - 5 EUR per m² area|
|Counter battens bearing (at Rooftop and on-roof insulation)||approx. 5 - 9 EUR per m² area|
|battens||usually approx. 7 - 10 EUR per m² area|
Price-determining factors in battens
The following factors are decisive for the costs of battens: In the case of battens above all:
- slat cross-section (usually 30/50, but may be different, for example 24/60, 40/60 or 60/80)
- the respective wood sorting class (S 10, S13 or S15)
- wood moisture content (maximum 20% Standard, maximum 15% or 10% are higher)
- the use class for wood preservation (normal class 0, class 1 and 2 are possible - protection against insects and fungi)
For counter battens the price additionally determines:
- load capacity (not load-bearing without insulation, different load-bearing capacity for roof and roof insulation)
- also wood sorting class , Wood moisture content and use class for wood protection
- also the lath spacing
- also the lath cross section
- of the version (possibly with triangular strips on the sides)
For the battens on which the cover is fastened, the price is determined by:
- lath spacing (depending on cover and the covering materials used and their dimensions)
- Grading class, wood moisture content and wood protection class
- Crossbar cross section (between 24/48 and 60/80)
Roof insulation is only one option for roof insulation. The structure can be different, a possible (proven) structure looks as follows:
- timber formwork
- vapor barrier film
- insulation boards
- roofing membrane
The timber formwork replaced in this case, the basic battens. This results in a price difference - with the basic battens (as indicated above) about 3 - 6 EUR per m² to estimate, in the roof formwork, however, up to 16 - 30 EUR per m² roof area.
Depending on the price of
- the thickness of the wooden boards
- the execution (planed, unpolished, surface treated)
- wood protection class, wood moisture content
- the type of attachment
- size of the timber formwork boards
vapor barrier film
Here are different types of films used, their price also The following may differ:
|Type of foil||Price per m²|
|PE foil||5 - 9 EUR per m², depending on the thickness of the foil|
|Polypropylene fleece||9 - 12 EUR per m²|
|Aluminum composite foil||8 - 13 EUR per m² , depending on the thickness of the film|
A roofing membrane needs every roof. Also in the case of our construction, a roofing membrane is used. As a rule, you can expect to get around 5 - 7 EUR per m² for the underlay.
Insulation panels made of mineral wool are mostly used for on-roof insulation, which is also the case with the above-discussed roof construction. The price of the insulation boards depends on:
- Type of insulation board
- Insulation board thickness
- Number of layers in the insulation layer (single-layer or double-layered)
- Thermal insulation capacity of the insulation board (various models have different capacities)
- Fire behavior class
- The compressive strength of the board
A brief overview of prices:
|Type of insulation board||Price per m²|
|Polystyrene rigid foam (EPS), 180 mm, 0.032W / (mK), Fire behavior B1||approx. 35- 50 EUR per m²|
|Polystyrene foam ( EPS), 180 mm, 0.032W / (mK), Fire behavior B1, TWO-DAY||approx. 40 - 60 EUR per m²|
|Polystyrene rigid foam (EPS), 180 mm, 0.032W / (mK), Fire behavior B1 EINLAGIG||approx. 70 - 90 EUR per m²|
|polystyrene rigid foam (EPS), 180 mm, 0.032W / (mK), fire performance B1, two-part||approx. 75 - 100 EUR per m²|
The roof covering can be made with very different materials. Detailed information can be found in our article about costs for roofing. In addition to the cost of covering the roof areas, you must also include the cost of the roofs and verges. These costs are usually calculated according to meters, and vary greatly depending on the cover material.
Concrete roof tiles
In our example, the roof was covered with concrete roof tiles. Other possibilities and their prices can be found in the article on prices and costs for roofing. For roofing with concrete roof tiles you have to expect about 25 - 30 EUR per m², for the higher quality, glazed (glazed) concrete roof tiles are between 30 and 40 EUR per m² to estimate. Depending on the stones used, you have to reckon with concrete roof tiles at about 30 - 50 EUR per meter (meters per meter) for ridges and verges.
Costs for additionally necessary work
In our overview we did not take into account some costs. For example, the eaves and the roof drainage still have to be designed and installed, in addition, smaller adjustments are necessary. The cost of the roofing scaffold we have, as already mentioned, left unconsidered here.
- lower insulation materials
- less use of insulating material (higher U value)
- cheaper roofing
- simply designed saddle roofs with simple geometry
- avoiding expensive factors
higher cost factors
- higher quality roof tiles
- dormer windows
- roof gutters and gutters
- more complicated roof shapes (hipped roof shapes, special roofs) Gable forms, etc.)
- additional skylights, roof exits, snow gullies, etc.
- elaborate gutter designs
- additional building designs
- extension of the roof overhangs
saving possibilities by self-construction or own contribution
There is no possibility for the performance of own work in the area of the roof. The DIY is not possible without appropriate expertise (roofer craft), and should therefore not be carried out.
In particular, a roof insulation also represents an energy renovation, and is therefore eligible. Information about possible funding can be found in our general funding overview.Tips & TricksThe cost of a roof can vary greatly. Therefore, not only compare individual companies, but also show you different alternatives and explain the advantages and disadvantages.