What types of resin are available for resin bound driveways?
The two main types of resin suitable for resin bound driveways are:
Aliphatic Polyurethane – UV stable – This is the best option for driveways, pathways and patios. The protection offered from UV will prolong the life of a driveway and also limit discoloration.
Aromatic Polyurethane – UV unstable – Exposure to the sun, specifically ultra violet rays from sun will cause discoloration over time because the resin will darken making the aggregate (stone) appear darker, too.
Which type of resin to use?
Aliphatic costs more but if a lighter aggregate is chosen this is the only way to go. In comparison, Aromatic Polyurethane is suitable if a darker stone is being used (because the darkening effect will matter less) and there are no areas in the shade.
Shade? What has shade got to do with it?
Well, if areas of your driveway are in the shade, the areas that still have exposure in the sun may discolour when an Aromatic resin is used. This will result in some areas looking much darker than others.
Will ruts (deep tracks) form on resin bound driveways?
The resistance to rut formation is very high for resin bound driveways. Tests have been conducted using 3mm, 6mm or 10mm aggregate. Frequent turning of front wheels of a vehicle (especially on a gradient) will increase the risk of rut formation. Therefore, it’s a good idea to ask the following questions at the planning stages.What vehicular motions are needed? Straight in and out? Reverse and turn? Weight of vehicle/s?
If resin is just like glue, does the bonding stay strong?
Generally, two types of test are carried out during the manufacturing process for resin that can be used for the installation of driveways:
1.Heat testing – This is an important test to ensure resilience against prolonged periods of hot weather. Resin exposure to an average temperature of 70°C for 28 days to ensure suitability. Do you remember a hot spell of like that?
2. Water saturation test – As flooding is an increasing risk within certain regions. Therefore, resin is soaked with water at a temperature of 23°C for 7 days to test its resilience.
Outcome: The importance of these types of tests are to confirm that the strength of bonds (at a molecular level) is maintained. If a resin has been tested to these standards or those that go above and beyond the parameters outlined, the resin should be of sufficient strength for driveway use.
What happens if petrol or oil leaks onto my resin bound driveway?
Due to the chemical reactions caused by spillages of liquids such as petrol or oil, thinning of resin may occur, if left. Therefore it is important to remove any spillages as soon as possible. It should be noted, however, that resin bound surfaces generally have superior resistance to these types of spills.
What tests confirm this?
Typically, tests will have been performed for the following liquids with 2 to 7 day exposures:
- Hydraulic fluid
- Engine oil
- Battery acid
Battery acid, engine oil and hydraulic fluid will have the most impact if left.
What about surface water drainage?
The size of the aggregate used will impact surface water drainage on resin bound driveways. For optimal drainage 6mm or 10mm aggregate is best. If there are natural falls to bedding areas 3mm aggregate can also be used. If you think about it, a 3mm aggregate packs together much more tightly than a larger aggregate. Therefore, less water can escape which may cause drainage issues in prolonged, heavy rain conditions.
What depth is right for a resin bound driveway installation?
Generally the following depths are sufficient:
- 3mm aggregate – 12mm depth
- 6mm aggregate – 18mm depth
- 10mm aggregate – 22mm depth
Does the outside temperature have an effect on a resin bound driveway installation?
The ambient temperature range for the installation for resin bound driveways is 5*c to 30*C.
Installation should not be attempted if relative humidity is greater than 78% or if temperatures are heading below 5*C.
Top TiP: Check met office site. (before installation!)
What type of sub base can resin be applied to?
A suitable Tarmacadam (asphalt) or concrete sub base surface will do and for best adhesion, the sub base must be completely clean and dry.
- No oil, petrol or diesel
- No loose stone
- No ice or frost
Can grids be used for resin bound driveways?
Yes. Increasingly, grid type systems are being used as part of sub base installations. If you opt for these, ensure appropriate aggregate (and compaction) is complete before the application of resin.
More on grid systems
What technique is best to mix aggregate (stone) with resin for best finish on resin driveways?
Step 1. Resin mix with slow speed, high torque drill and paddle for minimum of 45 seconds.
Step 2. 1-2 minutes in a forced action mixer.
Step3. Lay immediately!
Should a catalyst be used?
A catalyst reduces binding time. Therefore in warmer temperatures catalyst use will be at an installers discretion if they consider the resin may set too quick.
What tools are used for resin bound driveway installations?
As long as mixing is done close to the area of application using a spazzle and then troweling in should be sufficient. Larger areas may require using a screed box
Why it’s important to use ‘kiln dried’ aggregate (stone) on resin bound driveways?
Kiln dried is another way of saying ‘bone dry‘. Resin must fully bond to the surface of any aggregate. Therefore any moisture can affect this and cause discoloration and weaker bonding will result between stone and resin. To prevent this, kiln dried stone ensures no moisture is present.
Anything else you want to know about resin bound driveways? Let us know or fill in your details in the form on the right.
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Finally, the finished look and colour of any driveway installation are important! If we’re honest most ‘buying decisions‘ are based around these things. Equally important, however, is that attention is paid to some of the technical aspects outlined above.
We are always curious to know your opinion. Let us know in the comments below!