This base kit is made up of the following items:
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Weed membrane for each pad
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Plastic grids with pea shingle fill
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Concrete pads with height adjustable metal connector brackets.
A big advantage is that you do not have to dig deep trench or pile foundations - only shallow holes need to be dug to get rid of any vegetation and get down to virgin soil, then the plastic grids are laid on the weed membrane within each hole and filled with pea shingle (for stabilisation) and then finally the concrete pads are laid directly on top of these.
That's the foundations complete once the pads are laid out to the prescribed dimensions as shown on the plan that is provided with them. Extra sole plates are available if the ground slopes, enabling you to build the lower ons up to the same level as the highest pad.
The timber base is then built on top of these pads using large section tanalised timbers, joist hangers and coach screws (again, as set out on the plans).
The price of this heavy duty raised timber base is dependant on many factors (size, weight of building on top of it, design of building, etc) - we can quote you for this once we know the various parameters.
NB - If the building needs to comply with building regulations, it will need a full set of structural calculations (these vary with soil type, slope of the ground etc). We are able to provide these calculations at a cost - price is dependant on how large and complicated the design is.
If the customer supplies a hardcore sub-base, then this needs to comply with the following specifications -
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The area of hardcore should be large eough and square enough to fit the base onto plus "250mm all round" so that no plinth rest on the very edge of the sub-base (which might otherwise settle and break away over time).
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The hardcore should be very flat and "blinded" such that there are no large undulations or surface voids.
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The hardcore should be level to within 40mm (the plinths have 50mm of height adjustment). Otherwise extra costs will be incurred to build the plinths up to level.
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The material should be compacted to a high standard, commonly 95% of the maximum dry density as determined by the Modified Proctor test (often cited as 95% Modified Proctor in engineering specifications).
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Key requirements for compacted hardcore include:
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Compaction Method: All hardcore layers must be compacted using heavy equipment, such as a vibrating roller or vibrating plate compactor.
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Layer Thickness (Lifts): Hardcore should be laid in layers not exceeding 150mm to 200mm, with each layer thoroughly compacted before the next is applied.
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Thickness: A minimum of 150mm compacted hardcore is usually required, with any depth over 300mm requiring layering.
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Material Quality: Hardcore should conform to standards such as BS EN 13242 and be free from large voids, organic matter, or substances that could cause degradation (e.g., reactive pyrite).
