A new roof for the old house - what costs are incurred?

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.

Exemplary Example

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 stepCosts total
Renew rafters322 EUR
Roof insulation (roof insulation)15.618 EUR
Covering cpl. Renewing, roof formwork and vapor barrier2.980 EUR
Roofing with concrete roof tiles5.782 EUR
Total basic costs24.702 EUR
TipsMore details on the listed works can be found in our service description.

Note

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.

General

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.

Basic operations

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).

Renewing battens

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 lathingCost per m² of roof surface
Basic lathingapprox. 3 - 6 EUR per m² area
Counter battens, non-load bearingapprox. 3 - 5 EUR per m² area
Counter battens bearing (at Rooftop and on-roof insulation)approx. 5 - 9 EUR per m² area
battensusually 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)

On-roof insulation

Roof insulation is only one option for roof insulation. The structure can be different, a possible (proven) structure looks as follows:

  • rafters
  • timber formwork
  • vapor barrier film
  • insulation boards
  • roofing membrane
  • battens
  • roofing
timber formwork

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 foilPrice per m²
PE foil5 - 9 EUR per m², depending on the thickness of the foil
Polypropylene fleece9 - 12 EUR per m²
Aluminum composite foil8 - 13 EUR per m² , depending on the thickness of the film
Underlay

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

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 boardPrice per m²
Polystyrene rigid foam (EPS), 180 mm, 0.032W / (mK), Fire behavior B1approx. 35- 50 EUR per m²
Polystyrene foam ( EPS), 180 mm, 0.032W / (mK), Fire behavior B1, TWO-DAYapprox. 40 - 60 EUR per m²
Polystyrene rigid foam (EPS), 180 mm, 0.032W / (mK), Fire behavior B1 EINLAGIGapprox. 70 - 90 EUR per m²
polystyrene rigid foam (EPS), 180 mm, 0.032W / (mK), fire performance B1, two-partapprox. 75 - 100 EUR per m²

roof covering

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.

Conservative factors

  • 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.

Promotion

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.
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