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Translating high quality research specific to better design and building practice
Translating high quality research specific to better design and building practice

Grab rail installation into fibreglass showers or modular units

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The main issue with grab rail installation into fibreglass is fourfold.

  1. Fibreglass exposure from working with it;
  2. Waterproofing;
  3. Fibreglass cracking; and
  4. Ensuring that the attachment surface is suitable in terms of load etc.

Fiberglass is the trade name for a man-made fiber that also may be called fibrous glass or glass wool. A fiber is a particle that is at least three times as long as it is wide. The main fiber-forming substance in fiberglass is glass.

1. Information for Trades and DIY’s

Health effects from exposure to fiberglass can be different depending on the fiber size and type of exposure. Larger fibers have been found to cause skin, eye and upper respiratory tract irritation but no long-term health effects should occur from touching fiberglass. There are other possible health effects though such as:

  • A rash can appear when the fibers become embedded in the outer layer of the skin.
  • Eyes may become red and irritated after exposure to fiberglass.
  • Soreness in the nose and throat can result when fibers are inhaled. Asthma and bronchitis can be aggravated by exposure to fiberglass.
  • Temporary stomach irritation may occur if fibers are swallowed.

Little information is known about the health effects caused by small fibers. Smaller fibers have the ability to reach the lower part of the lungs increasing the chance of adverse health effects.

You can take steps to reduce your exposure to fibers when working with materials that contain fiberglass:

  • Wear loose fitting, long-sleeved clothing and gloves. This will reduce skin contact and irritation.
  • Wear a mask over the nose and mouth to prevent breathing in the fibers.
  • Wear goggles or safety glasses with side shields to protect the eyes.
  • Open a window or a door to increase ventilation and reduce dust levels.
  • Use a shop vacuum after wetting the dust and fibers.

Additionally, measures can be taken to reduce exposure after a person has come in contact with fiberglass. For instance, eyes should be flushed with water and any area of exposed skin should be washed with soap and warm water to remove fibers. Clothing worn while working with fiberglass should be removed and washed separately from other clothing. The washing machine should then be rinsed thoroughly after the exposed clothing has been washed.

2. Waterproofing
Any puncture of the fibreglass can lead to waterproofing issues and all holes will need to be carefully sealed once fittings are secured. In order to create a watertight seal it is important to apply sealant (typically a a clear silicone, which will likely not be paintable).

After application of the sealant it must be left to cure according to its manufacturers instructions. Additionally, a number of sealants must not be in contact with oil-based caulking, polysulfide and fillers impregnated with oil, asphalt or tar or the waterproofing seal can fail.

3. Fibreglass cracking

Fibreglass is flexible and bends when weight is placed on it and this may cause cracking. Fibreglass cracking is best prevented as water can leak on to and damage the sub floor. Additionally, the water that seeps out can stagnate and cause the growth of mould. Improper installation and incorrect selection of fixings is the most likely cause of fibreglass cracks and for this reason having an appropriately licensed tradesman with experience of fibreglass is important.

3. Ensuring that the fixings can withstand the intended load

AS1428.1 specifies that all rails must be able to withstand 1100 N of force in any direction and in order to achieve this, the materials used to construct the wall behind the fibre glass shower or bath shell needs to be ascertianed in order to ensure that the fixings can be appropriately anchored.

Fiberglass bath and shower enclosures require that you mount the grab rail to a solid brick wall or to a wooden stud, but the space between the wall/stud and fiberglass must also be filled with something or the fiberglass will bend as you tighten the mounting screws. So it is important that you use special anchoring hardware for hollow backer shower enclosures. These anchoring systems will support the grab rail in spite of the void behind the enclosure.

4. Anchoring hardware used in a shower enclosure

A number of special grab rails are marketed for this sort of problem such as the US produced Solid Mount™ which can be purchased on Amazon. This rail is designed for installing a grab rail into fiberglass bathroom fixtures. It is installed through the face of the fiberglass unit and uses a patented mounting assembly that attaches to the wall or a stud, sealing the hole and leaving a mounting surface to which a standard grab rail can be easily attached. In Australia, contacting your local hardware store about appropriate fixing options is recommended prior to attempting any installation and taking a picture of the unit with you may also prove useful.

The clearinghouse has a number of other publications regarding grab rails more generally which are helpful in deciding preferred location, diameter and purpose etc.

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