Level access showers can improve quality of life for disabled users. Peter Mayer of BLP Insurance looks at the design options and lifecycle costs for retrofitting them into existing floors
Increasing awareness of lifetime needs and incorporation of accessibility as part of the sustainable housing agenda are driving the specification of level access showers. When carefully planned as part of a new-built housing development, the additional costs are minimal. This is far from true for those who are adapting an existing room for level access. The cost and disruption will vary with individual buildings.
Level access showers are the most common adaptation within the Disabled Facilities Grant provisions and costs vary enormously from £1,000 to over £10,000 for the complete installation. Most adaptations cost between £4,000 and £10,000.
Key design criteria for the flooring construction of level showers are succinctly summarised in the draft British Standard, DD 266, code of practice for Lifetime Homes and BS 8300 designing to meet the needs of disabled people. The floor finish should be as level as possible within the constraints of incorporating a fall (one in 50) to ensure water drains away from circulation areas; the floor surface should be slip resistant and water tight; and the space requirement is at least 1m x 1m for the shower. Slip resistance is determined to BS 7976 and high slip resistance values are preferred.
PVC is a commonly installed surface finish. PVC may be specified to BS EN 13553 for use in special wet areas for both PVC to BS EN 649 and PVC with foam backing to BS EN 651.
Achieving falls to existing floors can be disruptive especially if the structural floor needs to be adjusted. The least disruptive solution is to install a 22mm-thick, preformed glass reinforced plastics (GRP) board in place of the existing floor decking, in the case of timber floors. The GRP board is shaped to falls within its thickness and includes a preformed drainage opening. These are made from a variety of plastics and resins including materials with sustainability benefits, such as recycled plastics.
Concrete or screeded floors offer different issues. The area requiring falls can be cut out and re-laid to create the fall. To avoid slumping of fresh screed, a grid of plastic formers can be used to maintain the correct falls and levels. Grinding the screed to required falls may be an option. Alternatively, screed can be cut out and a preformed plastics board inserted to provide a level access surface.
A key issue with retrofitting a level access shower is ensuring waterproofing. The design needs to be well thought out with a “belt and braces” approach. This is most important when forming installations on timber floors which are subject to thermal and moisture induced movements.
It is advisable to install a proprietary waterproofing system under the floor and wall finishes. Adhesives and sealants should be able to accommodate expected movement while retaining their waterproofing function. Particular care should be taken at junctions and services penetrations.
Using an inset GRP shower tray to provide both the falls and surface finish is an alternative to insertion of a preformed substrate which is subsequently covered with a floor covering. GRP trays are less than 22mm deep and are inserted into the floor following removal of the timber decking. The GRP trays should be slip resistant, although this is generally not quantified. The success of an insert level access shower tray depends on ensuring a good seal between the tray and the adjacent floor finish.
A ramped or low-level access shower tray with pumped waste water system is commonly used where costs and disruption is prohibitive.
Broader life cycle cost issues
The lifecycle cost assessment of level access flooring alternatives is focused on the costs from the owner’s perspective. The point of view of a local authority might be very different if the costs of installing a level access shower enable a person to be provided for by home-based care rather than residential care, with payback periods of a few months. There are also intangible benefits to quality of life and dignity.
Further information is provided by the Centre for Accessible Environments and the Health and Safety Executive for guidance on slip resistance.
BLP Insurance provides latent defect insurance for building www.blpinsurance.com
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Table notes Net present values calculated with 3.0% discount rate for a 60 year period. Capital costs include preparation of existing floor to allow laid to falls surface, installation of new floor or shower tray - nominally 1m x 1m, floor drain and floor finish. Costs-in-use include inspections, allowance for minor works, for example clearing drain; floor covering and shower tray replacement. No allowance for cleaning. Costs of plumbing, wall finishes and enclosures etc are excluded from this analysis. The analysis assumes the plastic preformed board remains in place throughout the 60 years. Life cycle costs are indicative and are based on the average of capital costs and service lives. Costs for new or retrofit installations are proportional to the complexity of the design, size and access issues as well as materials specific costs. Service lives represent average lives.