Tf01-Single Layer Insulation Between Studs
Tf01 - Timber frame walls - Single layer – insulation between
studs
Advantages
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Low cost
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Readily available from local stockists
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Lightweight and easy to cut
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Much faster to install than rigid board which requires very
accurate cutting
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Sized to fit tightly between standard stud widths without any
cutting on site
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The insulation is compressible, where cutting is required cut
the insulation slightly oversize and friction fit between the
timber studs thereby preventing cold air penetrating through joints
between the insulation and the timber
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The insulation is fitted in one process
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Completely fire-safe non combustible product
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Improves acoustic insulation of the walls
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Crown FrameTherm is a Zero ODP and Zero GWP insulation
product
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The manufacture of Crown FrameTherm products has a very low
impact on the environment
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Products
Crown FrameTherm Roll/Slab is a lightweight
glass mineral wool available in both slab and roll form and a range
of thermal conductivities. Its manufacture has a very low impact on
the environment and is classified as Zero ODP and Zero GWP*
Knauf Breatheline is a breathable membrane with a polypropylene
non-woven coating on both sides.
* Ecohomes and Code for Sustainable Homes
classification
Typical construction
Inner leaf comprising 12.5mm plasterboard, vapour control layer,
Crown FrameTherm Roll/Slab between studwork, plywood sheathing and
Knauf Breatheline, breathable membrane. A 50mm cavity separates the
timber frame from the outer leaf, typically of brick. Other
cladding options, such as tile hanging and timber boarding can also
be utilised.
Performance
Thermal performance
- Crown FrameTherm Roll 40 –0.040 W/mK
- Crown FrameTherm Roll/Slab 35 –0.035 W/mK
- Crown FrameTherm Slab 43 –0.043 W/mK
- Crown FrameTherm Slab 38 –0.038 W/mK
- Crown FrameTherm Roll/Slab 32 –0.032 W/mK.
Table 41 gives U-values for typical prefabricated timber frame
walls insulated with Crown FrameTherm products.
Table 41: Typical U-values for
prefabricated timber framed wall with Crown FrameTherm between the
studs
| Insulation product |
U-values (W/m2K) |
| |
Thickness
(mm) |
Breather
membrane |
Masonry outer
leaf |
Tile/timber clad outer
leaf |
|
Crown
FrameTherm 32
|
140 (90+50) |
Knauf Breatheline |
0.26 |
0.28 |
| 90 |
Knauf Breatheline |
0.37 |
0.40 |
| 140 (90+50) |
Low E breather |
0.24 |
0.27 |
| 90 |
Low E breather |
0.32 |
0.38 |
|
Crown
FrameTherm 35
|
140 |
Knauf Breatheline |
0.27 |
0.29 |
| 90 |
Knauf Breatheline |
0.38 |
0.42 |
| 140 |
Low E breather |
0.25 |
0.28 |
| 90 |
Low E breather |
0.34 |
0.40 |
|
Crown
FrameTherm 38
|
140 |
Knauf Breatheline |
0.29 |
0.31 |
| 90 |
Knauf Breatheline |
0.40 |
0.44 |
| 140 |
Low E breather |
0.26 |
0.29 |
| 90 |
Low E breather |
0.35 |
0.42 |
|
Crown
FrameTherm 40
|
140 |
Knauf Breatheline |
0.29 |
0.32 |
| 90 |
Knauf Breatheline |
0.41 |
0.46 |
| 140 |
Low E breather |
0.26 |
0.30 |
| 90 |
Low E breather |
0.36 |
0.43 |
|
Crown
FrameTherm 43
|
140 |
Knauf Breatheline |
0.31 |
0.33 |
| 90 |
Knauf Breatheline |
0.43 |
0.48 |
| 140 |
Low E breather |
0.28 |
0.32 |
| 90 |
Low E breather |
0.37 |
0.44 |
Notes: The U-values have been calculated to BS EN ISO 6946:
1997 and BR 443. Studs assumed to be 38mm wide at 600mm centres
(allowances for sole plates etc, give a 15% bridging area for the
timber). Stud depth is taken to be the same as the thickness of
insulation specified. Thermal conductivity of timber studs is
0.120W/mK. Ventilated low emissivity airspace assumed to increase
the R value of the unventilated cavity to 0.29 Wm/K and
unventilated low emissivity airspace assumed to increase R value of
unventilated cavity to 0.44 m2K/W as specified in BR443.
Higher values can be achieved with proprietary products. Please
contact Knauf Insulation Technical Advisory Centre for calculations
that include specific products.
Fire performance
Crown FrameTherm is classified as Euroclass A1 to EN
13501-1.
Building Regulations state that external walls in domestic
construction shall achieve half hour fire resistance. In tests and
assessments carried out by TRADA Technology Ltd in accordance with
BS 476: Part 21: 1987, different timber frame external walls
incorporating Crown FrameTherm provided the required fire
resistance.
Installation
Knauf Insulation products are dimensioned to suit studs 90 or
140 mm at standard 600mm centres. The nominal thickness of the
insulation should not be greater than the nominal stud depth. Crown
FrameTherm Roll/Slabs are friction fitted between studs at standard
centres and are self supporting. Generally, two slabs fully fill
the space between sole and head plates for standard floor to
ceiling height.
A vapour control layer is stapled to the studs across the inner
face of the wall before fixing the plasterboard. The vapour control
layer should be free from holes. Any gaps should be made good,
tears repaired and overlaps and apertures for services effectively
sealed. Particular care is necessary around electrical boxes. Knauf
Breatheline or other standard breather membrane, or low
emissivity breather membrane should be stapled or nailed to the
sheathing board at maximum 500mm centres. It should be lapped so
that each joint is protected, with upper layers lapped over lower
layers to shed water away from the sheathing. Horizontal laps
should be at least 100mm wide and the membrane should extend below
the lowest timber member. Vertical laps should be at least 150mm
and be staggered.
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Typical specification
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External wall panels to be insulated between studs using Crown
FrameTherm 43*/40* /38*/35*/32*/ Slab*......mm thick
(*Delete as appropriate).
Insulation to be cut as necessary and friction fitted between
studs.
The breather membrane stapled*/nailed* to the sheathing and
extend below the lowest timber member (*delete as necessary).
Cavity barriers and fire stops should be installed as required
to meet the Building Regulations.
Alternatively, refer to NBS clause P10/210.
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Typical section
