LBNW Timber Supported Sub-Frame For Older Houses With Weaker Ceilings?
We come across a lot of weaker ceilings or ceilings with smaller joists than normal and we advise not to just board direct to the joists or batten and board directly to the joists because the ceiling joists are too weak to allow the additional boarding & storage weight (load).
With older terraced and detached houses pre WW2 and after WW2 when we
started building again we had a short supply of materials, so houses were
built to a very minimal specification.
Although the ceiling joists are adequate (in most cases) to support your ceiling only they were never designed to take any extra weight on them, so they must be strengthened or built above correctly to allow for the extra weight from boarding, storage items and you to walk about safely. By adding more support this will prevent problems in the future.
Insufficient strengthening or supporting of a storage floor will cause problems with weaker ceilings, and unfortunately a lot of "loft companies" out there are not aware of how to create strong safe storage sub-frames (storage platforms) in a loft. Installing directly or on some 3x2 batten only increases the load on the existing ceiling and will not strengthen it. Add your storage items, you, someone else and without the correct extra support your ceiling could essentially be dangerously overloaded!.
There is more to it than you think, see the pictures below? this shows the extra work that goes in to creating a leveled structurally supported storage platform (sub-frame). The sub-frame is supported by hangers in places where it cannot bear down on your existing joists for support, usually above the central area of a bedroom, near the light bulb in the room where there is no additional support. Hangers must be fitted to the purlins to help support and suspend the sub-frame, in most cases this is required before any boarding can be installed.
Cutting corners to falsely reduce quotes for loft boarding is common place in this industry, so this means using inadequate materials, inferiors products which will not conform to any regulations.
But is it really necessary to build a sub-frame?
You can get a load calculation done for your loft storage requirements before you have loft boarding installed, but this is not required and can be quite costly.
We do however, highly recommend extra strengthening and would be silly to ignore as anyone can see adding more weight to a ceiling without support can, and will, damage a ceiling beyond repair. Get a LBNW timber supported sub-frame and feel confident that your ceilings will never be over loaded
However, newer built properties (with a truss roof in the past 50 years
or so) are a little different as they have support from a web truss
frame that is installed in your loft every 600mm, this supports the roof
and ceiling all in one.
So our LoftZone raised loft floor sub-frame system can be installed directly to this type of ceiling to gain height above the insulation of 270mm, so you can create a storage area without removing or squashing any insulation. It is bad practice to remove or squash installation to board your loft for storage, and this is why your homes developer or builder will most likely not recommend using your loft for storage because of the cowboy methods used previously by unqualified and amateur companies.