The blue-colour RAVATHERM™ XPS extruded polystyrene foam thermal insulation can be used in a wide range of applications, owing to the following beneficial properties as a result of the closed-cell material structure:

• permanently high thermal insulation level
• negligible moisture uptake
• high strength and rigidity
• dimensional stability
• resistance to rot and deterioration
• simple and quick installation with only a small amount of waste.

RAVATHERM XPS 300 ST is excellent thermal insulation for

• outside insulation above rafters
• outside insulation on reinforced concrete
• complementary insulation above rafters
• renovation – additional insulation on the inner plane of rafters

BENEFITS

The RAVATHERM XPS 300 ST thermal insulation is manufactured by extrusion production procedure, the result of which is a homogeneous, closed-cell material structure, a smooth surface crust (called extrusion crust) and numerous favourable material properties:

• permanently high thermal insulation performance
• water and frost resistance,
• high compressive strength,
• high flexible rigidity,
• high vapor diffusion resistance,

which make the product suitable for fully meeting all the demands of the numerous application areas listed.

ADVANTAGES IN PITCHED ROOFS:

• “thermal bridge-free” assembly
• big slab size (60 x 240 cm)
• tongue-and-groove edge finishing
• high compressive strength
• permanently high insulation capability
• shrink-proof, age-resistant
• user-friendly

RAVATHERM XPS 300 ST provides several different solutions for new-buildings or renovated attics.

In the case of a visible roof structure and wooden panel cladding inside or of a reinforced concrete pitched roof slab, one of the best solutions is to install RAVATHERM XPS 300 ST for insulation above the rafters and wooden panelling or on outer plane of the roof structure. This thermal-bridge-free solution is an easy alternative to this complicated built-up roof structure hiding several sub-tasks and opportunities for errors, while it provides high thermal protection for the loft and other related constructional components, even during the construction process.

In the case of future loft extensions, or renovation of attic, the RAVATHERM XPS 300 ST is an excellent technical solution from the inside. At renovation, it can be added very easily, even without dismantling the existing structure, while insulation slabs are placed directly on the upper plane  of the rafters.

The dimensions of RAVATHERM XPS 300 ST are 60×240 cm (1,44 m2), with tongue-and -groove edges to avoid thermal bridges and for quick assembly.

Installation of RAVATHERM XPS 300 boards

IN PITCHED ROOFS
The installation of the thermal insulation has to be started from a plank with a height identical with the thickness of the insulation board, mounted in parallel with the eaves line. The RAVATHERM XPS ST boards are wedged into each other until stop in an offset bond along the edges in order to prevent thermal bridges.
On ridges, in roof structures, the gaps in connection joints are to be filled with PUR foam. The counter battens need to be drilled in advance to prevent them from rupture or slitting by the fixing elements. The fixing elements of thermal insulation boards and counter battens have to be sized by the designer.

INSTALLATION OF THICK THERMAL INSULATION BOARDS
In the case of implementing thick thermal insulation boards (≥120 mm), safe installation through the counter battens requires more densely installed fixing elements with special length and strength because of the increased stresses, which may involve a considerable increase in cost. In such cases, a double-layer installation of thermal insulation is recommended. In this case, the thermal insulation must be supported under the entire surface. This may be a reasonable solution also in the case of unevenness of reinforced concrete plates.
In the direction of the roof slope, impregnated fixing battens with 50/75 mm or 60/80 mm cross section have to be fastened through the watertight underlay to the structure – if that is placed under the thermal insulation. An alternative order of layers is offered if the vapour-permeable underlay is installed right on the surface of thermal insulation boards. In this case, a vapour-retardant layer is usually not needed under the thermal insulation, but the placement of a separation layer between the fixing battens and the concrete surface is recommended.
Between the fixing battens, accurately cut-to-size 50-mm or 60-mm thick RAVATHERM XPS boards have to be fixed using a solvent-free cold adhesive or PUR adhesive foam pointwise. It is recommended to adjust the battens to the board size. The lowermost row must be fixed to the roof slab also mechanically. It is recommended to fill wide connection joints with PUR foam. The second layer of RAVATHERM XPS has to be screwed continuously, in an offset bond through pre-drilled counter battens to advance installed fixing battens similarly to roofs with wooden structure.
This solution can be easily and reliably applied even for thermal insulations with a total thickness of 180–320 mm.

IN AGRICULTURAL BUILDINGS
RAVATHERM XPS 300 ST boards may be installed either over the roof structure or between the frames or below the plane of the frames or the supporting structure.

The RAVATHERM XPS boards must be installed in offset bond, with exact match. The largest distance between the at least two fixing points along the length of each board:
• for thicknesses 40 mm to 50 mm: max. 1.00 m
• for thicknesses 60 mm to 120 mm: max. 1.25 m.

The RAVATHERM XPS boards must be fixed by zinc-coated, large-head screws, plastic-plate screws or special steel clamps for fixing hard foams to the supporting structure. With the latter, the fixation may be hidden in the edge profile of the thermal insulation boards.

IMPORTANT
The permanent application temperature of RAVATHERM XPS products is max. 75°C.
At higher temperatures, the plates will melt and suffer permanent deformation.

RAVATHERM XPS products contain an – ecologically safe – flame-retardant additive, as a result of which they will be self-extinguishing under their ignition temperature, however, they will burn if exposed to an intensive ignition source.

RAVATHERM XPS products are resistant to commonly used construction materials not containing solvents or softeners (bituminous components without solvents, water-based wall protecting materials, lime, cement, masonry mortars and plasters, anhydrous gypsum etc.).
Certain organic materials, such as solvent-based wood preservatives, paint additives, solvents (acetone, ethyl acetate, kerosene, gasoline etc.) will cause softening, shrinking and damage to the material.
For gluing, solvent-free adhesives must be used. Follow the supplier’s guidance.
XPS products must not be exposed to permanent intensive direct sunlight.