The system is only as strong as the wall/floor/ceiling on which it is relying. Hence, a wall mounted system is only as strong as the wall whilst a semi-wall mounted system relies on both a rigid floor and a good wall.

The compressed system relies more on the floor than the ceiling: a rigid floor with a plasterboard ceiling is usually fine whilst a flexible floor with a solid ceiling is not.

Solid wall
Made of masonry, brick or concrete, it sounds true and solid when you tap it with your knuckle. It's ideal.

Plasterboard wall
If it sounds hollow and consistently crisp wherever you tap, it is most likely to be 12.5mm plasterboard on timber or metal studs. Using modern compression fixings a plasterboard wall will accept most domestic loads on your wall mounted or semi-wall mounted system.

Lath and plaster wall
If the wall sounds dull, hollow and somewhat inconsistent over the slightly undulating surface, you may have the worst wall - timber laths with ageing plaster.

Almost certainly, you will need to rely on the floor, ceiling and strengthened shelving system to achieve a desirable loading. Ask us for advice.

Perfect new wall
If you are able to specify a new internal wall, we recommend 12.5 mm plasterboard over 18mm plywood or MDF on timber or metal studs. We recommend that you do not try to position timber studs to match the shelves.

You can then use the wall mounted system to achieve the strongest and cheapest installation, probably more than saving the additional cost of your wall.

Rigid floor
When you jump on it, it does not flex. Without a carpet, it's the best for your semi-wall mounted or compressed system; with a carpet, it is less good.

Flexible floor
When you jump on it, it flexes or creaks. If you intend to use the floor, this is not ideal. A thick carpet with underlay will not help the load-bearing capability of this floor. Ask us for advice.

Solid ceiling
A steel beam or concrete. It's ideal for a compressed system.

Plaster/plasterboard ceiling
A continuous plaster or plasterboard ceiling can be used for a compressed system, preferably in conjunction with a rigid floor.

Other ceiling
A discontinuous suspended ceiling comprising tiles or similar is far from ideal for a compressed system. It may only be used after your ceiling contractor undertakes reinforcing work.