Ceiling Level Insulation
A "traditional" loft insulation solution with mineral wool
between and above ceiling joists.
 |
Type F1 sarking felt |
 |
Eaves ventilation |
 |
Crown Loft Roll 44 above ceiling joists |
 |
Crown Loft Roll 44 between ceiling joists |
 |
Crown Loft Roll 44 taken down to link with wall
insulation |
Products
- Crown Loft Roll 44 is made from glass mineral wool and formed
into unfaced rolls which are lightweight, flexible, resilient and
non-combustible.
Typical Construction
A pitched roof of timber trussed rafters with tiles or slates
on battens and sarking felt underlay or sarking board. Ventilated
roof space and plasterboard ceiling below.
Crown Loft Roll 44 is installed in two layers, the first layer
between the joists and the second layer across the joists. This
minimises thermal bridging through the ceiling joists.
Installation
The first layer of Crown Loft Roll 44, the same depth as the
ceiling joists, is laid between the joists. It should be taken over
the wall plate to link up with any wall insulation. Take care not
to block the eaves ventilation. The ceiling level insulation should
be butt jointed with the insulation in the sloping ceiling and
dwarf wall.
The second layer is laid at right angles to the ceiling joists,
with all edges butt jointed.
Performance
Thermal performance
Crown Loft Roll 44 has a thermal conductivity of 0.044
W/mK.
Typical U-values (W/m2K) of ventilated
cold roof with ceiling level insulation
| Product |
Thickness
(mm) |
U-Values
(W/m2K) |
| |
Between
joists |
Over joists |
|
| Crown Loft Roll 44 |
100 |
200 |
0.15 |
| Crown Loft Roll 44 |
100 |
170 |
0.16 |
| Crown Loft Roll 44 |
100 |
150 |
0.18 |
Notes: Joist sizes assumed to be 100 x
48mm at 600mm centres (8% bridging plus 1% for cross noggings). The
U-values have been calculated to BS EN ISO 6946:1997.
Use Crown Loft Roll 40 for improved thermal
performance.
Fire performance
Crown Loft Roll 44 is classified as Euroclass A1 to BS EN
ISO 13501-1.
Advantages
- Lowest cost solution
- High thermal performance
- Non-combustible product
- Easy to install
All Loft Conversion Solutions