Solution

Roof insulation from outside

Insulation of pitched roofs and flat roofs

 

Advantages

General advantages

  • best thermal insulation values
  • excellent heat protection
  • high soundproofing
  • high fire protection
  • ecological insulation
  • adapts to all unevenness seamlessly and without waste

The optimum solution in renovations

Subsequent insulation of sloping roofs above the cladding. Previously converted attic rooms can be insulated in this way without inconve-nience to the residents.
This technique is also used in new construc-tions (e.g. in solid wood elements).

Good to know

For correct installation of the underroof please note the regulations of the ZVDH (Central German Roofer Trade Association) and ÖNORM standards in Austria and the SIA regulations in Switzerland.
You can find exact details for planning and execution in our brochures.

Insulation of flat roofs

On many old residential buildings the upper ceilings of concrete are below a slightly sloping wooden construction as roof. Or these are so-called ‘ERTEX roofs’ in concrete. High loss of heat in winter and rapid heating-up in summer are inevitable.

With ISOCELL cellulose the empty space below the roof can easily be insulated at a later date. Complex and expensive roof renovation is not necessary. The costs for the insulation are recovered within a few years.

Installation procedure

  1. 01

    Install vapour retarder

    The old roof cladding is removed. The vapour retarder (e.g. FH FORTE) is laid above the rafters in so-called sub-top procedure and fixed at the side with laths or press-on strips. Airtight sealing is achieved with the AIRSTOP adhesive system.


  2. 02

    Double up the battens

    Old battens often do not provide enough space for today’s insulation standards. In order to allow for the insulation thickness the battens are doubled.


  3. 03

    Blow-in for covered roofs

    After completion of the sub-roof the cellulose insulation is installed. Within the cavity the fibres become matted to form a compact, seamless insulation mat.


  4. 04

    Injection

    On previously tiled roofs only a few tiles need to be removed to make room for installation work.


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Solution in detail

Component section

1) Concrete roof tiling
2) Wooden spruce battens
3) Counter battens (e= 80 cm)
4) Wood fibre insulation boar
5) Rafter
6) ISOCELL cellulose insulation
7) Pressure lath
8) Vapour retarder (e.g. FH FORTE, AIRSTOP DIVA+)
9) Open formwork / air
10) Plasterboard

Isometry

Component section

1) Concrete roof tiling or roof tiles
2) Battens spruce
3) Counter battens (e= 84 cm)
4) Roof underlay (z.B. OMEGA Roof underlays)
5) Formwork
6) Rafter / Beam
7) ISOCELL cellulose insulation
8) Pressure strips
9) Vapour retarder (e.g. FH FORTE)
10) Open formwork / air
11) Plasterboard

Isometry

Technical data

Building material Thickness of layer (mm) λ W/m K Fire classification (EN)
Concrete roof tiling or roof tile 50 0,7 A1
Wooden battens (spruce) 30 0,13 D
Counter battens 50 0,13 D
Wood fibre insulation board 60 0,045 E
Rafter 120 0,13 D
ISOCELL cellulose insulation 120 0,038 (AT/ EU) 0,039 (D) B-s2, d0
Vapour retarder 1 0,2 E
Open formwork/ air 24 0,13 D
Plasterboard 15 0,21 A2
Insulation thickness (mm) Insulation density (kg/m³) GWP (kg CO2 äqv./m²) PHI (Phase shift in hours) U-value** (W/m²k)
120 46 -11,99 10,2 0,236
160 46 -17,29 11,6 0,198
180 48 -20,19 12,4 0,184
200 48 -22,86 13,2 0,171
220 48 -25,54 13,9 0,16
240 50 -28,55 14,8 0,15
260 50 -31,25 15,6 0,142
280 50 -33,95 16,3 0,134
Building material Layer thickness (mm) λ W/m K Fire classification (EN)
Concrete roof tiling or roof tiles 50 0,7 A1
Wooden spruce battens 30 0,13 D
Counter battens (e = 84 cm) 50 0,13 D
OMEGA Roof underlay 1 0,5 E
Timber formwork spruce 24 0,13 D
ISOCELL cellulose insulation 220 0,038 (AT/ EU) 0,039 (D) B-s2, d0
Rafter 220 0,13 D
Vapour retarder 1 0,2 E
Open formwork/air 24 0,13 D
Plasterboard 15 0,21 A2
Insulation thickness (mm) Insulation density (kg/m³) GWP (kg CO2 äqv./m²) PHI (Phase shift in hours) U-Value** (W/m²k)
220 48 -38,71 11,3 0,194
240 50 -41,71 12,2 0,179
260 50 -44,42 12,9 0,166
280 50 -47,12 13,7 0,156
300 52 -50,24 14,6 0,146
320 52 -52,97 15,4 0,138
340 52 -55,70 16,2 0,13

References

Low energy house in timber construction

A low energy house in timber construction was erected in just over five months in Kuchl near Salzburg.
ISOCELL made a considerable contribution to this short construction time - the whole roof was  insulated from the outside in 2 ½ hours.
The builder was delighted!

Insulation of flat roofs in apartment buildings

It is so straightforward to make a well-insulated building out of an energy waster. The roofing contractor opened the roof in various places. The company LKI from Nidda-Harb insulated the 600 m² roof area with 30 cm ISOCELL in just a short time.