FAQ Gravels and Pebbles - Handy Hints for Gardeners
1. Are all gravels and pebbles suitable for driveways or pathways?
The only decorative gravel or pebble not suitable for use on driveways and pathways is Scoria, which is a volcanic rock and too brittle for such use.
2. Which gravels and pebbles are suitable for use as an inorganic mulch?
Any gravel or pebble can be used as an inorganic mulch. Customers are advised to use weed mat under inorganic mulches…if the mulch needs to be removed for any reason for e.g. to add organic matter to the soil, or install irrigation etc, it can be kept clean of any garden soil etc.
3. Which gravel or pebble is best suited to natural water features?
The most commonly used natural pebble is Random Nepean Pebble.
4. Do gravels and pebbles have a set lifespan?
Most gravel and pebble will last forever. The possible exception to the rule is Scoria. As a relatively soft volcanic material, Scoria is not suitable for use with vehicular traffic or where there will be heavy loads regularly travelling on it, as it will crush and degrade over time.
5. What is decomposed granite used for, and how should it be applied?
Deco® Granite is a graded minus 20mm decorative gravel, which can be stabilised and compacted as a hard wearing, decorative driveway or pathway. Deco® granite comes in 3 colours, brown, pink and gold, and should be stabilised with cement at 5%, or 1 bag of off‐white cement per tonne of Deco® Granite for pedestrian use, or 10%, or 2 bags of cement per tonne for driveways. Alternatively Deco® Granite can be stabilised with builders lime at 5%, instead of cement.
6. I have an existing concrete driveway/path, can I lay decomposed granite over the top?
No. Concrete provides a sub‐base without flexibility. This may result in the decomposed granite cracking due to expansion and contraction with changes in moisture content and temperature.
7. How is Deco® Granite laid?
Once an appropriate base is established, apply stabilised granite to the required depth (minimum 100mm) then compact with a vibrating 'whacker' plate. If the granite is too dry, puffs of dust will blow out from beneath the whacker. If this happens, lightly water before compacting again. Compact the granite to required levels adding more to lower areas. Established a level surface with a recommended cross fall of at least 5%. (Don't allow water to pond on surface). Follow compaction process while lightly watering with spray nozzle until water slowly soaks into the granite. Surface broom off any excess water and cement fines. Use water spray to clean off granite surface. Leave surface for 24‐48 hours to dry.
NB: Take care not to over‐water the granite before laying otherwise cement will rise to the surface causing a hard cement surface layer.