Flat roof insulation

Flat roof waterproofing and flat roof thermal insulation can be solved in one step with sprayed foam. Purfoam roof insulation is unbeatable for modernizing old and new roofs 

Flat roof waterproofing:

Closed-cell foam + UV protection (Polyurea)

Estimated daily progress:

With one team 250 m2 (3-5 cm)

Recommended thickness:

for waterproofing 3 cm, for thermal insulation min. 6 cm

Material density:

Closed cell with a body density of 45-55 kg/m3

Flat roof insulation

The use of closed-cell polyurethane foam during flat roof insulation is becoming more and more popular, as it solves the issue of flat roof waterproofing in addition to flat roof thermal insulation. More and more architects are designing with purfoam roof insulation in connection with new construction projects. Purhab flat roof waterproofing is most often used on old, sagging flat roofs. The technological advantage of this is that it is not necessary to dismantle and transport the old insulation (which would often be more expensive than making the insulation we offer). Purfoam is versatile and can be used perfectly on almost any construction industry surface, be it bitumen, concrete or wooden closing slab. The closed-cell foam is gap-free, so the risk of waterlogging is eliminated and the energy efficiency of the building is not reduced due to thermal bridges. The material used flexibly follows the movements of the roof, it does not crack, so it is not necessary to install expansion strips.

If you would like to read more about closed-cell foam, click here!

If the foam layer is exposed to the sun for a long time, it is important to provide UV protection. We seal the insulation against the harmful effects of the sun with a polyurea-based paint. This cover layer effectively protects the foam insulation and extends its life. If the Customer provides the purfoam with a different covering layer (for example, concretes it, cold wraps it, lays a gravel bed on it, or builds a green roof), the flat roof insulation receives adequate protection against the harmful effects of the sun, so no separate protective layer is necessary.

Read more about the UV protective layer here!

Problems with traditional insulation materials 

Low-quality flat roof insulation can significantly increase heating and cooling costs.

Due to the waterproofing of an outdated, tarred flat roof, the roof often gets wet.

Condensation may form on the ceiling of the upper level.

Most traditional insulation materials do not exactly follow the movement of the building, which can lead to small unevenness and cracks.

The complicated layering of traditional materials does not provide water and heat insulation at the same time. Tar roof insulation only guarantees water tightness. An overcomplicated layer order may contain more error possibilities. If the bituminous roof insulation fails, the dismantling and removal of the layers involves significant costs.

Rodents like to move into outdated insulation materials.


The solution: flat roof waterproofing with PURHABB

Closed-cell polyurethane foam is twice as efficient as conventional insulating materials (0.023 λ [W/mK]).

Even a minimum application of 3 cm thickness guarantees complete waterproofing.

Condensation and condensation problems are eliminated.

Purfoam roof insulation can allow moisture to pass through to a certain extent, so the building remains breathable.

The applied PU foam and the protective UV layer flexibly follow the movements of the building, so dilatation problems do not arise.

The simple layer system minimizes the chance of failure.

When insulating a flat roof, it is not necessary to remove the old insulation.

Rodents don't like foam roof insulation, and they can't find gaps where they can get in between the old insulation materials.


Flat roof insulation

Given that more than half of a building's heat loss is lost through the roof, flat roof insulation is of paramount importance. They often come to us just for the waterproofing/wetting of the flat roof, in which case we apply the foam roof insulation in the thinnest layer, 3 cm thick. Although this minimum thickness does not yet provide strong flat roof thermal insulation, even this 3 cm provides 100% waterproofing to the building. If flat roof thermal insulation is also a consideration, we will recommend a thicker layer. A 10 cm thick closed-cell foam insulation provides the same efficiency as a 20 cm thick traditional thermal insulation (e.g. cotton or step-resistant EPS).

Purfoam has been used for roof insulation in Europe for 60 years, and according to experts, it retains its effectiveness for up to 80 years. The polyurea UV protective coating that protects the foam is also extremely durable, if applied with proper expertise, it protects the flat roof insulation against environmental influences for decades. It is important to know that the protective layer is not recommended for long-term physical use. If the flat roof is used as a terrace, the Polyurea layer may be exposed to wear. In such a case, it is better to combine the foam with paving slabs, cold cover or protection with a gravel bed.

Are there any open questions? Click here to view the Frequently Asked Questions!

purhab roof insulation housing estate

Flat roof references

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