Topsoil and plants should not be present on the ground beneath the floor. There is no need for on-site concrete or sand blinding. A minimum void of 150 mm (225 mm in thick clay soils) is often required between the underside of the floor beam and the ground surface. This prevents damage to the foundation when vehicles drive over it.
The area directly underneath the flooring should be flat. If this isn't the case, you should level off the subfloor before laying down your floorboards. Make sure that any pipes, wires, or other underground structures are protected from damage by filling in around them with plaster or mortar.
If possible, don't put walls or ceilings directly underneath block and beam floors. The lack of support can cause damage to other parts of the house. If you must have walls here, make them load-bearing so they can bear the weight of anything that might be placed on top of them.
Block and beam floors are very durable. You should be able to clean dirt out from underneath yourself if necessary. If you can't get to it yourself, call a professional cleaning company.
To protect the floor from wet, concrete bases require an underlay with a moisture barrier, a damp proof membrane (DPM), or a separate barrier. If the subfloor is made of wood, the underlayment chosen will be determined by what is installed on top. If it is to be finished, as is most common, then a smooth surface-wood flooring or vinyl planks-should be used.
If the subfloor is not going to be finished, as is usually the case with dirt or other non-slip surfaces, a thin layer of sand or gravel is used as an underlay. This allows water to drain away from the house and prevents soil from entering through air gaps around windows and doors.
Concrete foundations are heavy so extra care should be taken not to damage the substrate during installation. The type of underlayment used will depend on how much protection the floor needs. If you want to use a concrete floor but don't want to pour a new foundation, consider these options: A install a DPM B install a concrete slab with an optional vapor barrier C install a concrete slab with a standard foam insulation package D install a dirt floor
Your local home improvement store can help you decide which method is right for your situation. Be sure to get advice from a professional if you have any doubts about whether or not concrete should be poured as a foundation.
Concrete flooring are most frequently grounded. Concrete at grade level is always believed to be at ground potential because it absorbs moisture from the earth and is an excellent conductor in direct contact with the earth. For this reason, any electrical wiring or cables that pass through a concrete basement floor must be protected by conduit or cable armor.
Concrete above grade level does not have to be grounded. The current belief is that if you're not going up into the attic, then you don't need to ground the house. The only time this isn't true is if there are metal panels in the ceiling containing electrical wiring or heating/air-conditioning ducts. In this case, the metal in these panels will not conduct electricity and therefore they do not need to be connected to your circuit breaker panel.
The best way to tell if concrete floors require grounding is to call an electrician and ask him or her. Some concrete floor manufacturers will label their products as requiring grounding, while others do not. If it's not labeled, then you can assume that it needs to be grounded.
The second way to tell if concrete floors require grounding is to check with your local building code department. Most cities require concrete floors in basements to be grounded for safety reasons.