What is Permeable paving?
The Littlehampton Brick Co SmartPave System is a permeable paving solution which allows stormwater to move through channels created by the special angle cornered shape of the brick into a prepared sub-base. The water can then pass through a secondary filter into suitable subgrade or be stored for controlled release or harvested for non-portable use.
Alternative systems provide for:
- Detention/treatment/infiltration into the surrounding soil;
- Detention/treatment/discharge to stormwater system;
- Detention/treatment/infiltration and overflow discharge;
- Detention/treatment/secondary treatment/discharge or re-use
Littlehampton Brick Co SmartPave Benefits:
- Low life-cycle and maintenance costs
- Helps control run-off to eliminate flooding
- Made from natural clay pavers NOT concrete.
- Naturally treats pollutants on-site
- Negates surface ponding
- Erosion is reduced with clay pavers
- No need for detention pits
- Safely collects, detains and discharges storm water without dangerous drains or pits
- Can recharge ground water base flows
- Roof water can also be discharged into sub-base
Elements of Permeable Paving
Typical Infiltration System:
This is a standard permeable paving design with infiltration system. This system features a permeable geotextile underlay so that the water can infiltrate directly into a suitable sub-grade. Infiltration rate of high volume can be achieved using this style of system even after many years of service (assuming a suitable native sub-grade is used).
The specification of the filter fabric may vary according to the application, end-use or site. Refer to your storm water project engineer for specification.
Typical Tank system:
This system is underlaid by an impermeable plastic membrane and is suitable for use where it is proposed to detain stormwater before releasing in a controlled manner, or where is possible to harvest the water for re-use.
The exact type of membrane can vary depending on the excavated surface. Specialist advice should always be obtained in regards to which type(s) are suitable for your project. Sand bedding or geotextile protection from puncturing will be required in some circumstances.
The impermeable membrane will prevent water from entering the sub-grade and helps preserve sub-grade structural integrity.
Additional options include: Infiltration and overflow, Tanked and directed for re-use, Tanked with additional treatment, Geogrid reinforcement for sloping surface or turning traffic.
When water is harvested using the Littlehampton Brick Co SmartPave system it can commonly be used for flushing toilets, irrigation of lawns and plants including other non-portable purposes.
Home gutter and roof water
A typical domestic residence can discharge water directly from the roof and gutters onto the permeable paving system surface or into the sub-base.For larger industrial buildings roof water runoff should be introduced to the sub-base by means of of a sump with a manhole cover adjacent to the paved area. Any roof litter including leaves and small twigs can be easily caught and cleared in the manhole
Planted tree surrounding
Using the Littlehampton Brick Co SmartPave system around trees in the load bearing soil areas. This enables the option to have a hard surface paved right up to the tree pits without causing problems to the trees. Moisture and soil respiration levels are paramount to the successful establishment and future growth of trees
With the use of permeable paving natural rainfall is far more easily accessible than previously possible this also dramatically improves soil respiration.
Salt damage resistant
As with all bricks and pavers manufactured by Littlehampton Brick Co, the permeable pavers range are manufactured from natural clay materials instead of cement or concrete based products.Because clay pavers are less porous than their concrete counterparts they are naturally more resistant to salt damage.
As with all pavers made from natural products, there can sometimes be slight variations in colour and finish. This is why Littlehampton Brick Co strongly suggests choosing products for your project from at least 2 or 3 different batches, then be sure to mix the packs when laying to minimise any noticeable colour variations.Clay and other permeable paving products can suffer from efflorescence.
*The information herein is a guide only, you should always be sure to consult your storm water engineer before attempting any construction works.
Always be sure to consult your storm water engineer for advice before attempting any work. The construction of permeable paving systems should be carried out after the completion of surrounding general site works and after topsoiling of adjacent areas to prevent the wash down of fine materials.
Sub grade levels should be excavated to the levels shown on site drawings or as recommended by the engineer. In the case of permeable paving systems where it is proposed to infiltrate; strip drains and falls are not necessary.
Vibrating plates or rollers should be used to compact the subgrade to the requirements of the specification. Prior to compaction all soft areas should be removed and filled with suitable replacement material to provide a stable subgrade.
Permeable paved areas should be firmly restrained with the use of kerbs or kerb haunching designed to suit the intended use.
For tanked systems, lay membrane taking care to overlap the joints by 300mm using double-sided tape. In the case of methane or high water table is present, a specialist heavy-duty membrane may be required, the joints should also be welded. If the sub-grade is rough, a layer of geotextile and/or sand may be required to protect the membrane. A filter fabric layer can be placed over the membrane to protect against puncture damage from the sub-base. If it is proposed to drain by infiltration to the sub-grade, use a filter fabric (instead of the membrane) to stop the ingress of sub-grade material into the sub base.
Sub base is generally comprised of two layers with a nominal combined thickness of 350mm. This can however be varied by the project engineer to suit site requirements.
The upper sub-base is a layer of 20-5mm stone up to 100mm thick
The lower sub-base layer is to be 63-10mm stone up to 250mm thick. It is recommended that the lower sub base should be placed in two separate layers and each layer should be compacted with a roller or vibrating plate. Compaction should continue until 95% of the compacted bulk density achievable under laboratory conditions has been reached.
Filter fabric should be laid on top of the sub base and joints should be overlapped by 300mm.
5mm crushed stone should be laid and loosely screed to a depth of approximately 50mm. Be sure that the final level of the 5mm stone is accurate. This is important as the stone will compact down much less that sand would when the pavers are vibrated. The particle shape of the 5mm stone will also affect the degree of compaction. A small trial area should be laid prior to construction to determine the accuracy of the final levels.
Laying the pavers
Generally permeable paving systems are laid in a 90° herringbone pattern but you can use other patterns with the Littlehampton Brick Co system. Just be sure to consult your pavior and storm water engineer before deciding on a pattern for your project.
It is recommended to have a single header course or double stretcher course of permeable pavers around the perimeter of the paved areas and also at the edges of any separately restrained areas such as tree pits. It is strongly recommended that pavers are taken from at least 2 or 3 packs and mixed during laying to minimise noticeable colour variations.
Where pavers need cutting they should not be cut smaller than 30% of the paver size and all cutting should be carried out using a disc cutter. Occupational health and safety requirements should be observed at all times.
The pavers should be vibrated with a high-frequency, low amplitude vibrating plate compactor. The use of carpet or something similar will help prevent marking the paver surface. Following the first pass with a vibrating plate, spread the light dressing of 3mm single size clean stone at the rate of approximately 1-2kg/m² over the surface and brush into the joints. The pavers should be vibrated once again and remaining debris brushed off.
The sub-grade should have a minimum CBR of 5 (or sub-grade compaction of 90%). Engineering advice should always be obtained regarding the sub-grade before starting work.
Membrane (typical) Dimensions: 4m x 12.5m x 50µm – 23kg. Tear resistance: 40N/mm minimum Tensile Strength: 14.4mPa Durability: The membrane must remain flexible and not degrade. It shall be resistant to UV light and puncturing.
Where methane or a high water table is present in the subgrade it will be necessary to use a heavy-duty membrane and to weld the joints. The membrane should be protected against puncturing.
The grade will vary according to the precise application. Always consult the project hydraulic or storm water engineer for specifications.
The granular sub-base material should comprise of crushed gravel, rock or concrete possessing well defined edges. It must be sound, clean and non friable. The material must be non plastic. The crushed stone used for laying the course and sub-base must have a minimum 10% fines value of 150kN
Sub-base lower layer:
A 250mm deep layer of stone. Grading to comply with:
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Sub-base – Upper Layer:
A 100mm deep layer of graded 20-5mm crushed stone.
The upper filter fabric grade will vary according to the precise application. It is always best to consult with your storm water or hydraulic engineer about which filter fabric would best suit your individual needs.
50mm depth of 5mm single size (near as possible) clean crushed stone.
3-5mm single size clean stone applied at the rate of approximately 1-2kg/m²
Specification of the strip drains should be provided by the project hydraulic or stormwater engineer.
The Littlehampton Brick Co SmartPave range is available in ALL of the beautiful colours in the pavers range. This is possible because all our Permeable Paving solutions are made to order. Some include popular favourites like Old Red, Hills Gold and Mahogany.
Permeable pavers have a manufacturing time of at least 2-6 weeks as they are made to order for every customer.
For more information or precise delivery times it is best to visit us in our factory direct showroom at:
Littlehampton Bricks and Pavers
North Terrace, Littlehampton, SA 5250
or call us on:
08 8391 1855