CRAWL SPACE INSTALLATIONS
Crawl space installations are flooring repairs or a new floor done in older houses with a suspended wooden floor. The original floors will be made up of joists and beams topped off with a solid wood floor. The space under the floor is not always accessible and may have an earth base. Moisture conditions under these floors are higher than normally found in a house, and will vary with the seasons.
The original flooring and floor structure were generally made up of what is commonly referred to as Oregon Pine. The timber that was used was fairly rot resistant, and when installed all those years ago would have been air dried to a moisture content of around 18% or more.
The floors and the structure under the floors deteriorate and wear out in time. A tongue and grooved floor plank can only be sanded to a point just above the groove before its useful life as a floor board is at an end. The structural timber also suffers - especially where it is in contact with bricks or concrete - the high moisture levels under the floor eventually causes rot and insect damage and the floor will start to collapse.
Replacement of these floors is not as straightforward as simply installing new flooring as was done when the house was built. Modern practices now mean that all our flooring products are kiln dried to a much lower moisture content -normally between 6% and 8% - than in the "old" days. Installing this, much drier, flooring in a high moisture environment causes the floor boards to swell as they absorb the moisture in the surrounding air in an effort to get into equilibrium. The expansion of the floor boards causes the floor to become uneven as the boards cup, and lift up off the floor joists resulting in a floor failure.
At Derrington Floors we use the method prescribed by the SA Wood, Laminate and Flooring Association to install new floors in a crawl space - and are staff are accredited by the Association for this installation type. New floor joists would be CCA treated pine - this timber is treated to make it rot resistant. Layers of moisture barrier and a layer of shutterply are used to isolate the flooring from the moisture in the crawl space - once this has been done we can install any of our flooring products as a final finished floor.
The process is a fairly time consuming and costly - but will ensure your new floor will last as long as the original one.