Gf06-Suspended Timber Floor
Gf06 and Gf09 - Ground Floors - Suspended Timber Floor
Advantages
- Crown Loft Roll 44/40 is manufactured to suit standard joist
spacings
- Insulation friction fitted between joists, with tight fit
against timber
- Non-combustible insulated product
- Crown Loft Roll 44/40 is a Zero GWP and Zero ODP insulant
- The manufacture of Crown Loft Roll 44/40 has a very low impact
on the environment.
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Products
Crown Loft Roll 44 is made from glass mineral
wool and formed into unfaced rolls which are lightweight, flexible,
resilient and noncombustible. Its manufacture has a very low impact
on the environment and is classified as Zero ODP and Zero GWP*
Rocksilk Flexible Slab is a multi-use Rock
mineral wool flexible friction-fit slab for use in a range of
acoustic, thermal and fire resistant applications. Its manufacture
has a very low impact on the environment and is classified as Zero
ODP and Zero GWP*
* EcoHomes and Code for Sustainable Homes
classification
Typical construction
A suspended and ventilated timber ground floor. The insulation
is placed between the joists and supported on polypropylene
netting.
The netting should be positioned to support the insulation so
that there is no gap between the insulation and the underside of
the floor deck. The floor joists running parallel with masonry
walls should be spaced at least 35mm away from the wall to allow
insulation to be placed next to the wall.
To minimise air leakage at the floor perimeter, the skirting
board should have a self-adhesive strip of expanding foam applied
to its lower edge and a continuous bead of sealant applied to its
back surface before fixing.
The wall insulation should start a minimum of 200mm below the
top of the floor insulation to minimise thermal bridging.
Installation
If the insulation is the full depth of the floor joists, staple
the support netting to the underside of the first joist and unroll
the netting, stapling to the underside of each joist as the netting
is unrolled.
Where the joist is deeper than the floor insulation, mark the
depth of the insulation on the side of the joists. Staple the
support netting along this line and pull taut to the adjacent joist
and staple again. Pull the netting over the top of the joist and
staple to the depth of the floor insulation. Repeat the process
until there is netting support to the whole floor.
Unroll the Crown Loft Roll 44/40. There should be no air gap
between the insulation and the underside of the floor deck.
Fix the chipboard floor deck in the usual way, using waterproof
PVA glue at the joints, and allow a minimum 10mm gap at the room
perimeter.
When fixing the skirting board, apply a selfadhesive foam strip
to the underside of the skirting and two beads of sealant to the
back surface. Apply pressure to ensure the foam strip is compressed
immediately before fixing the skirting in place.
Performance
Thermal performance
- Crown Loft Roll 40 has a thermal conductivity of 0.040
W/mK.
- Crown Loft Roll 44 has a thermal conductivity of 0.044
W/mK.
- Rocksilk Flexible Slab has a thermal conductivity of 0.037
W/mK, except 140mm thickness which has a thermal conductivity of
0.035W/mK.
Table 72 gives U-values for a range of perimeter/area
ratios.
Fire performance
Crown Loft Roll 44/40 and
Rocksilk Flexible Slab are classified as Euroclass A1 to BS EN ISO
13501-1.
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Typical specification
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Polypropylene netting to be (draped over and between the joists
and stapled to the sides of each joist*/stapled to the underside of
the joists*). (*delete as required)
Crown Loft Roll 44*/40*/Rocksilk Flexible Slab* of ......mm
thickness and of width to suit joist spacings, supported on the
netting to fit tightly under the floor. Crown Loft Roll
44*/40*/Rocksilk Flexible Slab* to be cut and placed to fully fill
in the gap between the last joist and the perimeter wall. T&g
flooring grade chipboard to be fixed to the floor joists, all as
specified by the designer.
Alternatively, refer to NBS clause: P10/240 or P10/250
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Typical section
Table 72: U-values of suspended
insulated timber ground floor
| Solution |
Thickness
(mm) |
Ratio of Perimeter (m) to Area (m2) |
| |
|
0.10 |
0.20 |
0.30 |
0.40 |
0.50 |
0.60 |
0.70 |
0.80 |
| Gf06 |
Crown Loft Roll 44 |
| 300 (150+150) |
0.10 |
0.12 |
0.13 |
0.13 |
0.14 |
0.14 |
0.14 |
0.14 |
| 250 (100+150) |
0.11 |
0.13 |
0.14 |
0.15 |
0.16 |
0.16 |
0.16 |
0.16 |
| 200 |
0.12 |
0.15 |
0.16 |
0.17 |
0.17 |
0.18 |
0.18 |
0.18 |
| 150 |
0.13 |
0.17 |
0.19 |
0.20 |
0.21 |
0.22 |
0.22 |
0.23 |
| 100 |
0.16 |
0.21 |
0.24 |
0.26 |
0.27 |
0.28 |
0.29 |
0.30 |
| Crown Loft Roll 40 |
| 250 (150+100) |
0.10 |
0.13 |
0.14 |
0.14 |
0.15 |
0.15 |
0.15 |
0.15 |
| 200 |
0.12 |
0.15 |
0.16 |
0.17 |
0.17 |
0.18 |
0.18 |
0.18 |
| 150 |
0.13 |
0.17 |
0.19 |
0.20 |
0.21 |
0.22 |
0.22 |
0.23 |
| 100 |
0.16 |
0.21 |
0.24 |
0.26 |
0.27 |
0.28 |
0.29 |
0.30 |
| Gf09 |
Rocksilk Flexible Slab |
| 250 (100+90+60) |
0.10 |
0.12 |
0.13 |
0.14 |
0.14 |
0.14 |
0.14 |
0.15 |
| 200 (100+100) |
0.11 |
0.14 |
0.15 |
0.16 |
0.17 |
0.17 |
0.17 |
0.18 |
| 140 |
0.13 |
0.17 |
0.19 |
0.20 |
0.21 |
0.21 |
0.22 |
0.22 |
| 100 |
0.15 |
0.20 |
0.23 |
0.25 |
0.26 |
0.27 |
0.28 |
0.29 |
Notes: The U-values have been calculated using BS EN ISO
13370: 1998 and BS 6946: 1997 and assume 48mm wide joists at 600mm
centres.