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New Construction or Renovation: The 4 Most Important Tips for Your Roof Project

New Construction or Renovation: The 4 Most Important Tips for Your Roof Project

A new building or roof renovation will be a success if you plan ahead. We have compiled the five most important pieces of advice for your successful roof project for you. For a quote or better assistant, contact Missouri Commercial Roofing Pros of St. Louis.

1. What do you want for your new roof? With good planning to the perfect roof!

Externally, the shape and covering or sealing of the roof determine the appearance.  For perfect protection against wind, rain or heat, however, a few inner values are still important. To achieve this, the roof structure, dormers, thermal insulation and roofing or sealing must be stable and weatherproof.

There are many possibilities for roof design, but not everything is allowed: Keep an eye on the development plan, because it determines how building is allowed in a residential area. Accordingly, it is important that you look ahead and plan your roof project well.

The thermal insulation

A building can lose a lot of energy through the roof. You can successfully counteract this with sufficient thermal insulation. This will save you energy and money for heating or an expensive air conditioning system. And of course you protect the environment.

Pitched roofs are insulated in three possible ways:

  • Rafter-mounted insulation is laid as a sheathing on the roof truss and under the roof covering.
  • The above-rafter insulation is placed between the rafters from the inside.
  • The under-rafter insulation is applied as an additional layer from the inside.

For flat roofs, there are the warm roof, inverted roof, and cold roof solutions. They differ in the order in which waterproofing, thermal insulation, and roof construction are arranged.

  • With warm roofs, the thermal insulation is placed on the roof construction and is protected by a bitumen seal.
  • In the inverted roof, the thermal insulation and the waterproofing are reversed so that the insulation is again protected by the waterproofing.
  • Cold roofs have a free space filled with air between the thermal insulation and the sealing.

Different construction methods have different advantages and disadvantages. Your roofer can best explain which of these methods is ideal for your flat roof.

Observe the requirements for the thermal insulation of buildings set out in the German Energy Saving Ordinance (EnEV) (see “Applying for subsidies”).

Roofing and sealing

The expert does not say “cover” but “seal” with flat roofs. Because the sealing does not always have to form the top layer: With a reversed roof, the waterproofing lies beneath the roof insulation.

To seal the flat roof, the roofer chooses between bitumen membranes and plastic membranes:

  • Bitumen is made from petroleum. But for a bitumen sheeting, renewable raw materials such as jute are also used. Usually a roofer lays bitumen sheeting in two layers. One disadvantage of bitumen is that it can melt when exposed to high heat. Polymer bitumen membranes are modified with elastomers and are therefore more heat-resistant.
  • Polymer bitumen membranes can be made of different types of plastic, e.g. PVC. They are also known as roofing membranes. Plastic sheeting is extremely flexible and therefore easy to process. One layer is usually sufficient.

Your roofer knows exactly which material is suitable for your flat roof. You should also clarify whether and how you want to use the roof area. Your roofer will then help you choose the right waterproofing material for your roof. During the construction of a flat roof depends mainly on its use, all pitched roofs have one thing in common: the roof covering is their top layer. The variety of materials is correspondingly large.

  • Roof tiles (roofing tiles and roofing stones): Traditional clay roof tiles are light and versatile. Roof tiles made of concrete are very similar to clay tiles on the outside, but heavier and more accurately fitting. In general, there are many colours and shapes of roof tiles to choose from.
  • Slate: Roofing made of this natural stone is robust and durable. The slates are nailed to the roof construction. This makes slate roofs very resistant to bad weather. Many variations of slabs and construction methods allow for a variety of designs for your roof.
  • Titanium zinc is available in many different forms of sheet and web. This makes this metal an ideal material for dormers and gables. Another positive property of titanium zinc is its high life expectancy and resistance to weathering.

Solar systems: Solar thermal and photovoltaic

With a solar system, you can produce electricity and heat yourself: Photovoltaics generates electricity, solar thermal energy generates heat. Due to their weight, solar systems place an additional load on the roof construction. You should, therefore, check in advance whether your roof construction can withstand a solar system.

Once this has been clarified, three further factors play a role in ensuring that a solar system can fully develop its benefits: The orientation of the solar system, its inclination and shading. Ideally, the system should be oriented to the south at an inclination of 30° to 35°, with no obstacles – such as trees or other buildings – between the system and the sun. With a flat roof, you can usually align the solar system as required. With a pitched roof, the orientation of your roof influences how effective a solar system is. Your roofer or carpenter can advise you individually on this topic.

Extensions, roof windows, green roofs: additional benefits for your roof

From a habitable attic to a roof garden for your flat roof – with an attic conversion you can improve the coziness and value of your property with foresighted planning. With roof extensions of all kinds for pitched roofs and flat roofs, you should have it checked whether your roof truss or roof construction can bear additional weight. Only an experienced roofer or carpenter can reliably detect possible structural damage, for example caused by mould or woodworms.

Whether children’s room or hobby room, skylights and dormers let sunlight into your attic. You can have roof windows installed according to your ideas. Dormers increase the living space, but you need a permit from the building authorities, because their installation affects the statics of your roof construction. As with all roof work, impeccable thermal insulation is important to prevent heat loss and mould.

You can upgrade a flat roof, for example, with a flat roof greening or as a roof terrace. In this way, you can improve the thermal insulation of your flat roof and the air quality, or you can comfortably enter and use the roof surface. It is important here that not only the roof construction of the flat roof but also the insulation can bear the additional weight.¹³

2. Find the right roofer: Your roof project is a job for professionals

The roof of your house is a complex and – in the truest sense of the word – multilayered construction: pitched or flat roof, coverings and coverings, insulation materials and ventilation require a high degree of expertise and knowledge. Whether new construction, renovation or repair – let only professionals work on your roof.

3. An offer you do not want to refuse: This is what you should bear in mind when making an offer for your roof project

In order to select the right roofer or carpenter for your roof project, you should first receive an offer from them. In this offer, either individual steps or the entire work will be indicated with a corresponding price. A cost estimate, on the other hand, is first and foremost an estimate of the necessary work and costs. Note: A quotation is binding, a cost estimate is usually not – it can exceed the price quoted by up to 20 percent.

You should pay attention to the following points when making an offer: A good quotation clearly indicates the time required for the work. With the commitment period, a roofer or carpenter commits himself to complete your roofing project within the specified time, under the specified conditions and at the price offered. For up to 20 kilometers of travel, the travel allowance is up to 20 euros. In the case of larger orders, the offer should clearly state whether the journey is charged at this flat rate or as working time.


  • Pay attention to specific details regarding the material costs: In the case of estimates, you cannot exclude the possibility of additional unforeseen costs. 

A good roofer will arrange an on-site appointment with you to have a careful look at your roof. Only then can he prepare a serious and individual offer for you.

4. The cost issue: the cheapest offer is not always the best

With a new building or a roof renovation, you invest in a job that must serve you well for a long time. When it comes to the roof, quality and good work have their price. You pay for the competence and expertise of your roofing or carpentry company and for efficient and durable materials.

Saving in the wrong place can cause you more costs in the long run than it saves. Because poor workmanship or defective materials in your roof mean that it cannot fulfill its task as desired. Possible consequences are damage caused by weather and moisture, increased costs for heating and repairs. In the worst case, you may even have to repair your roof or have it repaired soon.

High quality of material and workmanship causes higher costs, but also a long service life of your roof. If you calculate the costs down to the lifetime, the investment will pay off in the long run.

Your roof project: When will you pay? Advance payments

Avoid unpleasant surprises by keeping an eye on your roofer’s payment terms. In principle, a roofer or carpenter is obliged to finish your roof. Only when he has completed the roofing project without defects may he charge you for his work and the cost of materials.

An exception to this rule are so-called payments on account: Through these partial payments, the roofer or carpenter can reduce his own risk. With large projects and high material costs, advance payments are common.