Flat roof insulation
Insulating a flat roof can be done in two ways. Both insulation methods require the necessary knowledge and experience of insulation, insulation materials and the method of installation. Which insulation method is best for your flat roof depends on several factors. Learn more about flat roof insulation options and associated costs on this page, among others.
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Why insulate a flat roof?
Insulating a flat roof is quite effective, since a lot of heat is lost through the roof. With a pitched roof, heat has to rise further up the roof to be lost, whereas with a flat roof, heat travels faster near the roof and is therefore lost faster.
Insulation of a flat roof thus ensures that heat is retained longer in the building and you need to heat less to keep the building warm. Over time, you save on your energy costs and often recoup the investment in just a few years. Insulating a flat roof is also an environmentally conscious and good choice.
Different types of insulation methods flat roofs
There are different methods of roof insulation for flat roofs. Depending on your needs, the existing roof construction and free space, we will choose the best insulation method in your situation. The different types of roof insulation for flat roofs are:
Warm flat roof
Insulating a flat roof using the warm roof method involves insulating the flat roof from the outside. The advantage of this is that the roof structure is also insulated.
Cold flat roof
Insulating a flat roof according to the cold roof principle means that the flat roof is insulated from the inside. The supporting structure of the roof is not insulated.
Inverted flat roof
Reverse insulation of a flat roof involves laying the insulation on top of the existing roof covering. This type of insulation is commonly used on roofs that are walked on, such as the roof of an extension or shed.
Warm flat roof
The most commonly chosen insulation method for flat roofs is the warm flat roof principle. The insulation is installed on the roof structure from the outside. The roof structure is therefore located in the insulated space and this has the advantage that shrinkage and expansion in the roof structure is greatly reduced. Indeed, the roof structure is exposed to temperature fluctuations to a much lesser extent. The roof also remains walkable, to a greater or lesser extent.
Structure insulation hot flat roof
To prevent condensation of moist air in the insulation material, first of all a vapor control layer is applied. The insulation boards are placed on top of the foil. The insulation boards often consist of EPS, perlite, PIR or Styrofoam, because these materials hardly expand or contract. On top of the insulation boards comes the roofing material, which may be additionally finished with tiles, gravel or other options.
Benefits of insulating hot flat roof
The main advantages of this insulation method:
- Excellent insulating effect;
- Provides roof protection in addition to insulation;
- Corner of roofs are easy to insulate.
Disadvantages of insulating hot flat roof
The most commonly observed disadvantages of insulating using the warm flat roof method:
- Risk of damage to existing roofing materials;
- Implementation of the project only possible under proper weather conditions;
- It is an intensive project.
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Cold flat roof
Insulation using the cold flat roof method is usually chosen only when insulation using the above method is not possible due to limitations. In this insulation method, the insulation material is placed on the underside of the roof boarding. Thus, the roof structure is not insulated and is still continuously exposed to all kinds of weather influences, with all its consequences. But at all times, better a cold flat roof insulation than no insulation.
Cold flat roof insulation
In the case of a cold flat roof, the insulation material is fixed between the beams of the roof boarding. In the case of a concrete ceiling, a wooden structure will be made in the form of a suspended ceiling, into which the insulation material will be incorporated.
Advantages of insulating cold flat roof
The biggest advantages of a cold flat roof:
- When insulation using the warm roof principle is not an option, insulation using the cold flat roof method is better than no insulation;
- Less labor intensive.
Disadvantages cold flat roof
The biggest disadvantages of a cold flat roof:
- There is a risk of condensation with this form of insulation;
- The roof structure is not co-insulated and will continue to be exposed to weather conditions and temperature fluctuations. This can eventually cause damage to the roof structure.
Inverted flat roof
This insulation method is called the inverted flat roof principle. We often see this method used in remodeling or renovations where the existing roofing is still in good condition, but there is still a desire for additional insulation.
Build-up insulation inverted flat roof
In this method, the pre-existing roofing is used as a waterproofing layer. On top of the existing roofing, sheets that are resistant to moisture are placed, usually XPS sheets. On top of the insulation boards, aggravating material is placed, such as tiles or gravel.
Advantages of inverted flat roof
The main advantages of this insulation method:
- No vapor barrier required;
- Less labor intensive;
- Easy to implement and therefore more economical.
Disadvantages of inverted flat roof
The biggest disadvantages of this insulation method:
- Difficult to insulate in the corners of the roof;
- Finishing with aggravating material requires additional load-bearing capacity of the roof structure;
- Poorer insulation than the warm flat roof method.
Flat roof insulation costs
The average cost of insulating a flat roof depends on the method you choose, the area of the roof and the materials used. Prices can vary by choosing different materials. To give you an idea of the average costs for insulating your flat roof we have made the following overview for you:
| Methode plat dak isoleren | Plaats van de isolatie | Gemiddelde kostprijs per m² |
|---|---|---|
| Warm plat dak | Isolatie langs buiten | €65 – €110 (incl. afwerking) |
| Koud plat dak | Isolatie langs binnen | €27,50 – €37,50 (excl. afwerking) |
| Omgekeerd plat dak | Op de bestaande dakbedekking | €45 (incl. afwerking) |
*The above prices are an average price for guidance. Would you like to know exactly what you will pay for having your flat roof insulated? Then ask us for a free, no-obligation quote.
Bitumen roofing
Over the years, the use of bitumen roofing materials has increased dramatically. The most common type is polymer-based bitumen, such as SBS and APP. These materials are very strong and resistant to cracking because they are coated with fiberglass or polyester. APP is resistant to high temperatures and UV light, which is why this material can be used well without finishing with a ballast layer. SBS sticks better than APP, but is more sensitive to high temperatures and sunlight. SBS is additionally finished with a protective layer to allow application without a ballast layer.
EPDM roofing
This form of roofing is very durable and lasts up to 30 years. EPDM is a synthetic rubber and can be placed on the roof in one custom-made piece. The specialists at Roofers 24/7 glue the EPDM sheet onto the roof or attach it using hot air. In the latter option, special EPDM foil is attached to the inside of the sheet, when heated this becomes liquid and the EPDM sheet can be attached. The disadvantage of EPDM is that there can be problems with the seams and connection of the edges.
PVC roofing
Another form of synthetic roofing is PVC. PVC is a plastic film available in rolls. Our specialists attach the PVC in overlapping strips with glue or by hot air. While this type of roofing is more sensitive to UV rays and sunlight, the seam and edge connections are often better than EPDM. PVC roofing can also be used on top of an existing layer of bitumen if a special foil is used.
Green roofing
A green roof is usually insulated using PVC roofing membrane combined with a fiberglass reinforcement. This protects the membrane from root growth.
Get a quote for your flat roof insulation by Roofers 24/7
At Roofers 24/7, we think it’s important to work hard, but also to be transparent. We provide you with a customized quote that includes more information than just our prices. After your quote request, you will receive our quote within 24 hours at the email address known to us. We will contact you a few days after the quote is issued for any additional questions and/or comments. For more information or to request a free, no-obligation quote, please email info@dakdekkers247.nl or fill out the contact form on our contact page. You can request a quote by phone by calling: 06-40125121.
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