Sealing windows – ecologically and with system!

No matter which installation option you choose, our laminated fleeces are suitable for both types of installation and are ideal for vapor Diffusion-tight sealing of windows. At the same time, the fleece can be plastered over directly - an optimal solution in the window connection area. For faced window systems, we alternatively recommend our durable aluminum-coated butyl rubber tapes or our sealing tape with tear-resistant and screw-through-proof film.

In 3 steps to the perfect window sealing

Sustainable window sealing with butyl rubber tapes

Installation variants of a butyl sealing tape:

  • The classical one: The widely used L-variant installed directly on the window frame (right picture).
  • The insider tip: Our double-sided adhesive DUO-VARIANTE. Take advantage of space-saving installation, both for system buildings and prefabricated houses (left picture)!

Sealing windows environmentally friendly

Ecological construction with EGO products


FAQs about sealing windows

A good sealing function and temperature resistance, among other things, are very important here. The conditions of the structure must be taken into account when selecting a suitable waterproofing system. In the case of renovations, structural restrictions often exist, which require professional execution in accordance with the recognized rules of technology to ensure long-lasting functionality.

The sealant should meet the following requirements to ensure that the joint seal will function properly for many years:

  • airtightness
  • UV resistance
  • temperature resistance
  • chemical resistance.

It is necessary to consider occurring movements at the construction connection joint, which are caused e.g. by different thermally induced linear expansions and deformations.

Every facade is composed of 3 functional levels.

The weather protection level has to prevent the ingress of driving rain from the outside and has to ensure the leakage of moisture from the inside to the outside.

In the functional area, especially the attributes of thermal and sound insulation must be ensured. This area must 'stay dry' and separated from the room climate.

The separation layer between the room and the external climate should be visible over the entire surface of the building components and the external wall and cannot be interrupted. The construction has to be airtight on the room side. The separation has to be made in a layer which temperature is above the room climate which is critical for mold growth.

Connection joints are joints between two building components, such as between a wall and a window or exterior door. These must be sealed with permanent elasticity to compensate for the movements occurring at the building connection joint, which are caused, for example, by different thermally induced linear expansions and deformations.

The thermally induced changes in the length of the window profiles cause the sealant to expand, compress and shear. In order for the sealant to be able to absorb these movements in the long term, a properly defined joint dimensioning is required. Connection joints therefore must be planned and executed individually, under consideration of the respective construction situation. The minimum joint width required for connection joints is determined by the dimensional changes of the frame profiles due to temperature and humidity as well as by the ZGV of the sealant used.

For example, due to the occurrence of air drafts, accumulation of moisture, up to whistling noises when the wind blows. The leaks often occur due to old rubber seals in the window rebate and/or joints between the window frame and the window sill. The connections to the building structure should be visually inspected regularly and checked for damage and cracks.


For the larger temperature fluctuations in the outdoor area, an elastic sealant with a permissible total deformation of 25 %. On the room side, a sealant with a ZGV of ≥ 12.5 % can be used.

The "inside tighter than outside" rule always applies to ensure that moisture that has penetrated the space between the two walls can drain away to the outside. The water vapor Diffusion resistance must be higher than that of the exterior joint and at the same time ensure an all-round airtight seal. 

The connecting joint on the outside must be permanently sealed to be windproof, driving rain-proof and weather-resistant. The water vapor Diffusion resistance must be lower than for interior sealing, since the trapped water is to be discharged to the outside. This type of construction ensures that moisture that has penetrated the joint can migrate to the outside.

Connection joints must be planned and applied individually, under consideration of the specific construction situation. EGOFERM MIT VLIES DUO, EGOFERM MIT VLIES and EGO UNIVERSALVLIES as well as sealants such as EGO SMP 818, EGOSILICON 300 and EGOSILICON 360 are suitable for sealing.

The connecting joints between the building component and the building structure must be windproof, driving rain-proof and open to Diffusion in the long term.

With a BLOWER DOOR MEASUREMENT. This is a measuring procedure that uses overpressure or underpressure to perform an airtightness test of the building's outer shell. It provides information on the energy efficiency of the building. The Building Energy Act (GEG) also requires that the heat-transferring enclosure surface, including the joints, is permanently airtight in accordance with the recognized rules of technology.

Compared to 1-component PUR foams, EGOMAT achieves high strength with simultaneous controlled and rapid curing without moisture supply and can be cut after approx. 10 minutes and loaded after approx. 120 minutes.

This is different depending on the product group

  • -40 °C to + 100 °C for SILICON, SMP HYBRID or EGO Butyl
  • -20 °C to +80 °C for ACRYLATE

Special silicones, such as EGOSILICON 300, have even been proven to have resistances from -60 °C to +150 °C.

Besides sprayable sealants, other products can be used depending on the constriction and the requirements, such as impregnated sealing tapes, sealing foils, elastomeric waterstops and joint profiles.

Yes, a silicone can also be used for exterior construction joints, taking into account the particular construction situation.

For interior joints, acrylates, SMP's and sealing tapes are generally used.

Yes, for reasons of moisture, sound and heat protection, the joints in the functional area must be filled all around. This is also necessary in relation to the requirements of the Building Energy Act (GEG). The materials used are mineral wool, foam tapes, cork, flax and, above all, PUR assembly foams.

EGOPREN C1 joint sealing tape is used for the external driving rain-proof sealing of connection joints in window and building construction between the frame and masonry and is self-adhesive on one side to aid installation and treated with a special acrylate impregnating agent. The sealing tape laid in the joints relaxes depending on temperature and time and thus adapts to the joint widths and unevenness of the building components. EGOPREN C1 can be plastered and painted over.

EGO UNIVERSALVLIES is cut with an excess length, the foil is removed and glued frontally to the frame. First of all, the bottom is glued horizontally, then the two verticals and finally the gluing of the upper horizontal end is carried out. After that, the gluing is done to the masonry.

EGOFERM MIT VLIES is a one-sided self-adhesive Butyl rubber-based sealing tape, which is laminated with a synthetic fleece and can be plastered and painted over.

EGOFERM MIT VLIES DUO is double-sided, i.e. alternately adhesive, and can therefore be easily applied to the frame before installation. After mounting the window frame in the wall reveal, the foam can be filled and EGOFERM MIT VLIES DUO can be glued into the reveal. In accordance with the principle "tighter on the inside than on the outside", the sealing of window connection joints on the room side of the window is recommended with the sealing tape.