Roof
roof pitch
Drempel
Flat roof
Upper floor slab
Solid ceiling
timber-beamed ceiling
Nail binder
Attic conversion
External wall
Façade
Partition joint in a house
cellar wall
Ground floor
cellar ceiling
Stairway to the cellar
Solid ceiling
Cap ceiling
Timber joist floor/cavity
Special components
Many older buildings have a floor hatch with a built-in pull-down ladder, or simply a hinged cover against which a ladder must be placed, to provide access to the loft. These are usually uninsulated and have draughts. As a result, a great deal of heat escapes in winter and a ‘chimney effect’ occurs, allowing indoor air to escape through leaky joints. The consequences are draughty and cold hallways and unnecessary energy loss. The thermal barrier between the (unheated) loft and the heated interior consists of a wood-based panel that is no more than 2 cm thick.
A very good, but somewhat labour-intensive solution is to replace the loft hatch and stairs with a new, pre-insulated loft ladder. A more cost-effective option, which can even be carried out as a DIY project, is to retrofit insulation using high-performance insulation materials with the lowest possible thermal conductivity. These are simply stuck to the outside of the hatch cover. It’s best to insulate the reveals at the same time. For leaky hatches, rubber sealing strips glued into the grooves of the hatch cover provide a solution.
Which insulation materials are suitable? High-performance insulation materials (sheets or mats) combined with a proper air seal are best suited for this insulation measure.
- Phenolic resin boards WLS 021
- Aluminium-laminated PU WLS 023
- Aerogel mats WLS 015 (for situations where the installation height must be kept to a minimum)
You will also need:
- Sealing tapes
- Possibly a new latch/locking mechanism
Please note: As the wooden steps rest directly on the insulation board, using the loft ladder afterwards may be slightly more difficult.
How do you do it?
- Determine the maximum possible insulation thickness. This is determined by the space between the wooden panel and the ladder structure resting on top of it.
- The wooden panel is glued to the insulation board over its entire surface.
- Go up into the loft and ask someone to close the loft hatch.
- From above, the sides and reveals of the loft hatch are then insulated so that they are flush with the insulation board.
- Ensure that there are no gaps in the bonding.
- Ask another person to reopen the loft hatch and stick sealing tape all the way round the edge of the hatch.
- In most cases, it will then be necessary to fit a new ‘latch’.
Time required: 2–3 hours.
Cost: If you have the floor hatch insulated by a specialist contractor, you can expect to pay around €150. If you carry out the work yourself, you’ll only incur the costs of the insulation, sealing tape, adhesive and a new latch – these amount to around €30 per floor hatch in total.
The maximum possible insulation thickness should be selected (usually 3–4 cm).
All the benefits at a glance
Improved thermal insulation: Insulating the floor hatch improves the thermal performance of this component by 80 per cent. This can be seen from the so-called heat transfer coefficient (U-value). Heat transfer coefficient (U-value) of a floor hatch:
- before: approx. 3 W/(m²K) (watts per square metre per kelvin)
- after: approx. 0.6 W/(m²K)
The building’s heating costs are reduced only slightly, as the floor hatch is a small component, but: “Every little helps”.
Further advantages:
- The old floor hatch does not need to be replaced
- Draughts caused by leaks are eliminated
- The rooms under the roof become more comfortable
- Fewer climate-damaging carbon dioxide (CO₂) emissions are produced
- A very cost-effective insulation method that pays for itself within a few years
- The insulation work can be carried out in just a few hours
- Also suitable for DIY
