We call the skyward part of construction (Sky) roofing, roof framing, waterproofing, or waterproofing terrace.

Regardless of the structure's type of construction (wood, metal, mineral), the roof of a building is a lightweight structure. The classical roof frame has the following elements: the hood (tile, shingle, various boards), the support for the roof system (wooden slats), vapor barrier (perforated foil, membranes), roof decking (boards, plywood, OSB), supporting structure (wood, metal, reinforced concrete), the inner plating (drywall, paneling), and a finish. Between the deck and the interior plating in the enclosed structure (rafters, made wall plates, manes), cavities are formed in which the permissive to air/vapor and convection thermal insulation settles (mineral wool, blown fibre).

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For low rise construction, the largest part of the heat is lost through the roof, an estimated 30% of the total losses (25% walls, 20% ventilation 13% windows, 7% floor, 5% thermal bridges). Although the roof is the area most exposed to the weathering and gets a greater amount of heat and vapor from the inside due to the upward flow of warm air, the thermal insulation is the most unstable, with a more than permissive lin-up. Detrimental conditions are exacerbated by the shape, the skew-horizontal position, sun exposure, the wind, rain, and frost. Most often, thermo-insulating materials placed in cavities do not even reach 20% of the thermal insulation (U, R, λ) value specified by the manufacturer for that particular type and thickness of the product.

The reason for this drastic reduction is the permeability to air-vapor, dampening due to condensation, and mainly looping convection. Because of the differences in pressure between the cold and warm air, cold air will bypass or penetrate the leaky thermo-insulating material with no sealing towards the cavity edges. Warm vapor is moving from warm to cold and is forced to condense somewhere in the thermo-insulation, roof decking, or even behind the interior coating.

We all know the result: oppressive heat during the summer in the attic and largely increased heating consumption in the winter time. The less visible things are the condensation, the mould and the degradation behind of the drywall (interior finishing). In most cases, within a few years, a mould-contaminated odour will appear as a result of fungi.

The roof framing is a type of cavity wall without the ability to garner moisture from condensation and is detrimentally exposed to climatic factors and to processes that cause energy loss.

Sealing the attic is done only with the inner plating and finish (drywall, polishing plaster coat). The layers that come into contact with the exterior (shingle, air/vapor barrier, roof decking) allow convection (air flow) and a very high heat transfer, making thermo-insulation worthless since it is being looped by the stream and air currents that carry heat and vapor. Condensation is practically inevitable for classical solutions with permeable thermo-insulation and air/vapor barriers. The energy losses are massive.

The ventilated wall solution (or the permissive attic thermal insulation) is definitely a failure felt by many of you, both because of the unhealthy indoor air quality and high energy bills.

Once again, the healthy, efficient, and correct solution comes from EIOS by applying the Principle of Avoiding Condensation.

Any building can benefit from the Zero-Moisture Concept and Technology by applying EIOS Sky system on the roof framing.

EIOS Sky system consists of applying the Non-Permissive Thermo-Insulating Assembly directly onto the roof decking. This provides the All-in-one water/air/vapor complete-barrier in a thermal insulation applied continually to an element of roof framing.

Note that EIOS Sky is applied like every other EIOS systems - without the installation of any air/vapor barrier in the form of foils, fabrics, membranes, or coats.

The achievement of EIOS Sky Thermosystem begins by analyzing the aspects of:

This analysis is done for free by EIOS experts and aims at establishing the thickness of the Thermo-Insulation and the cover fixture support details, the intersection with constructive elements and making a continuity between the EIOS Sky applied to roof framing and the adopted insulation system for walls.

The EIOS Sky thermo-insulating thickness influences thermal comfort and efficiency. It is established through the levels chosen by the owner without having to go down below a level accepted for the functioning of the Thermosystem.

Available EIOS Sky systems:

EIOS brings to the market the only framing roof applied Thermosystem that eliminates the problems associated with condensation, convection, stormwater, and thermal bridges.

Moreover, EIOS Sky is the first Thermosystem for roofs that eliminates thermal deck between the walls and the roof framing, accomplishing a continuity concept.

By creating continuity between EIOS Sky and EIOS System, the ideal thermal insulation is achieved in any season and is applied perfectly to an excellently insulated house. Besides the benefits of avoiding condensation and gaining maximum energy efficiency, the EIOS House guarantees a dry structure without mold and a pleasant interior both in cold and frost conditions as well as during the heat.

EIOS provides highly competent professionals to achieve the outlined objectives, both for the designer-architect, builder, applicator, and the owner.

EIOS Sky is a system of Over Specified Thermo-Insulation with an exterior application (Exterior Insulation Over Specified) that eliminates condensation through the use of extruded polystyrene XPS with sealed joints, while the EIOS Sealboard was invented to facilitate the impervious sealing of the Thermosystem assembly.


XPS boards tend to have zero permeability to vapor and water absorption. A Non-Permissive Thermo-Insulating Assembly is obtained through the significant thermal resistance R-value and expanding the EIOS Sealboard properties to the whole considered surface. This eliminates condensation by separating the warm vapors from cold areas through an impervious thermal insulation.

All specifications of this system are for outdoor application.

By applying the EIOS Technology for Avoiding Condensation, Thermo-Insulating becomes an exact science!

Areas of application:




The EIOS specialists are available for finding the complete and personalized technical solution for different types of roofing systems.

As mentioned, all adverse phenomena take place at maximum intensity within a roof framing wall type.

The air/vapor flow and convection are key variables in any type of roof framing. This is where there are massive heat losses in a brief amount of time. Everyone has noticed that the attic during the summer is stuffy and during the winter the heating systems do not cope but no one recognizes that this is a general problem due to a wrong thermo-insulation (permeable cavity insulation ventilated) and the improper concept of controlling water, air, and vapor in building enclosures.

EIOS Sky system not only ensures eliminating condensation and water intrusion, it also provides the drying of wood structure on which it is applied.

The transmittance and the thermal resistance (U, R) are achieved realistically, 99.9% EFFECTIVE without being reduced by convection, dampening, or thermal bridges. More insulation value is added by the roof decking, stuffy air, plasterboard, and other materials.

Additionally, the exterior thermo-insulating placement under the roof system increases the efficiency of this thermal insulation considerably by the fact that during the summer it does not get direct heat due to solar radiation, and it is permanently shadowed. In cold weather, it also protects the roof from the direct wind action, which also amplifies the energy loss.

However, an efficient ventilation from outside to outside is required between the EIOS Sky system and the roof hood.