Your NHBC Warranty and Raised Loft Storage Systems
We are often asked ‘Does installing Loft Leg XL’s in our loft invalidate our NHBC warranty?’ We have discussed this issue at length with the NHBC Technical Department and consulted a Chartered Structural Engineer to ensure we can provide the best possible advice to our customers. It is also important to clarify that this statement applies to all raised loft storage systems.
The NHBC responded with....
‘If it is installed by the homeowner it does not invalidate our warranty, but any defects found to result from the
installation of said system e.g. condensation or structural damage would not be covered by the warranty,
therefore homeowners install it at their own risk. This applies to any changes made to the building after the
warranty period has begun’
It is therefore imperative for our customer’s peace of mind that we confirm that installing Loft Legs XL’s will not cause the defects mentioned above. The NHBC has confirmed that....
‘Where access to loft space is provided, structural design is required to take account of live loading on ceiling
joists for the purposes of occasional entry and maintenance and a nominal live load allowance is included in
acknowledgement that homeowners are liable to place light, miscellaneous and infrequently used items, such
as might be suitable for spreading across widely-spaced joists, in the loft area’
Chartered Structural Engineers confirm the above is correct and that trusses in new homes that are fitted with a loft hatch should be designed to BS 6399-1:1996*. This states that the truss must be designed to carry a 25kg/m² loading for storage and a 90Kg load to account for a person accessing the loft.
Therefore we can confirm that a correctly installed and loaded raised loft storage system will not invalidate the NHBC warranty and that if the new house was constructed with a loft hatch then the trusses should have been designed to support a storage load of 25kg/m² and a 90kg person.
*Extract from BS 6399-1:1996
5.2 Ceiling Supports and similar structures
The following loads are appropriate for the design of frames and covering of access hatches (other than glazing),
supports of ceilings and similar structures:
a) without access: no imposed load: or
b) with access: 0.25KN/m² uniformly distributed over the whole area and a concentrated load of 0.9KN so placed as
to produce the maximum effect in the supporting members