Remap makes many outside objects such as ramps which require a non-slip finish. This article looks at some of the options available.
Commercial Non-Slip Products
There are a number of suppliers of non-slip products (as opposed to paints). Two of the better known are Suigeneris and Step-on-Safety. They make pre-fabricated glass fibre non-slip strips and covers to attach to existing structures.
Fabricated solutions include mesh attached to surfaces and paints and other finishes. These are commonly found in Remap jobs. In the discussion below it is assumed that the substrate is wood unless anything else is mentioned.
Attached N0n-Slip Materials
These include roofing felt, wire mesh and plastic mesh.
The use of roofing felt is deprecated. Although it provides a good non-slip surface it has little tear resistance and once torn rapidly becomes a trip hazard. It is difficult to maintain in good condition, soon looks shabby and in hot weather and especially direct sunlight becomes soft, fragile and liable to leach semi liquid bitumen which if carried inside on footwear will ruin any carpet it touches.
Chicken wire is sometimes used to provide a cheap non-slip surface on riverside jetties and the like. Small hole chicken wire is nailed to the surface using galvanised or stainless steel staples. The surface it creates is moderately non-slip but the wire strands are prone to breaking and creating a trip hazard. Once it starts to break up repairs are usually impractical and the surface has to be re-laid. The staples also allow for rainwater entry into the wood. On ramps it is not ideal as it looks cheap, hold dirt and debris and is difficult to maintain.
Plastic square mesh with a mesh size of 20-40mm has taken over from chicken wire in New Zealand where it is used to create non-slip surfaces on tourist walkways in temperate jungle. It is stronger than chicken wire, does not create as much of a trip hazard if broken and has better non slip properties. Visually it is slightly more acceptable than chicken wire. It is attached with staples in the same way.
These include Polyester Resin (fibreglass resin) and paints, both with non-slip additives.
Polyester resin is used in fibreglass manufacture but can also be used as a wood finish. It is a two part product comprising a resin and hardener. Once mixed it starts to set and must be applied immediately. It is usually unusable after about 10 minutes or so depending upon temperature. It must be applied to a clean dry surface. Because it sets very quickly it is difficult to paint the surface and then sprinkle on sand or other non slip substances, it has to be done quickly and a bit at a time. Once down the surface is long lasting hard wearing and easy to repair if required. Compared with paints it is generally more expensive but longer lasting. Powders used to provide the non slip surface include dry sand, carborundum grit and Fillite.
Paints and Varnishes
Oil based paints and varnishes have the advantage of an unlimited range of colours and familiarity. It is worth investing in a good quality oil paint and preparing the surface carefully. Non slip additives can be premixed with the paint or sprinkled on the surface before it can dry. Powders used to provide the non slip surface include dry sand, carborundum grit and Fillite.
Dry sand is cheap and easily available. It has moderately good non slip properties. It can be sprinkled on wet paint by putting some sand in a fine mesh kitchen sieve and tapping sieve while moving it over the paint surface about 3ft above it. After the paint has dried excess sand can be brushed away. Because it is a dense material (1.6g/cc) it isn’t easy to pre-mix with paint as it tends to sink to the bottom and creating an even surface finish can be difficult. It wears moderately well, is easy to retouch but difficult to obtain an even finish.
Carborundum grit is a more expensive additive and creates a very non-slip surface. The surface is sufficiently abrasive that if anyone falls on it they can get moderate abrasions. It is very hard wearing and for extreme conditions is probably the best finish. As with sand it is dense and doesn’t easily mix with paint. Probably the best way of applying it is to mix some with paint in a tray and apply with a brush. Agitating the paint in the tray with the brush will keep the carborundum mixed. You do not need a large amount to create a non-slip surface. To apply it to Polyester resin requires quick work, it is best sprinkled on the surface immediately the resin is applied.
If the ramp is to be used by people walking but unsteady on their feet carborundum may not be the best choice as it may cause them to stumble if their walking gait involves dragging or shuffling their feet – it is very non slip and footwear can’t easily slide over it.
Cost is about £15/5kg. and its bulk density is 1.64 to 1.88 g /cc. SG is 95 g/cc and it is rated 9 on the moh scale of hardness. There are many suppliers on-line, CFS have proven to be reliable.
Fillite is a powder extracted from pulverised fuel ash from coal-fired power stations.
Fillite cenospheres are lightweight, hollow, inert, spherical, low density, very free-flowing, alumino-silicate microspheres. It is used as a filler material in resin cast moulds and also as the non-slip additive for some marine deck paints. Because of its light weight and ball shaped granules it mixes well with paint or Polyester resin without sinking. It is usually available as a light grey powder and is inexpensive (typically about £2 to 5/kg or £35/20kg). bulk density is 0.35 to 0.45g /cc.
Mixed with paint or resin (after the hardener) it has very little effect upon the paint or resin physical characteristics so can be used with roller or brush and goes on evenly leaving a slightly matt finish. There are many suppliers on-line, CFS have proven to be reliable.
For most surfaces the best non-slip surface will be obtained by using paint with Fillite mixed into the paint at a ratio of up to 50/50 by volume. It is cheap, easy to apply as it mixes easily with the paint or resin has a good surface finish and gives good non-slip properties (significantly better than sand) combined with ease of repair and cleaning. Fillite mixed with Polyester resin can be used where very heavy traffic is expected.
For particularly challenging applications Carborundum grit is more difficult to apply but gives a very hard wearing non-slip solution.
Wire mesh and plastic mesh are inferior to both Fillite and Carborundum. They are more difficult to apply, not as long lasting, often look tatty after a short time, are difficult to repair and not as non-slip.