02 SITE, URBAN AND OPEN SPACES0411 Waterproofing – external and tanking
0243 Landscape – water features
Worksection abstract
This worksectionTemplateis applicable to self-contained water features in open landscaped areas.
Guidance text
All text within these boxes is provided as guidance for developing this worksection and should not form part of the final specification. This Guidance text may be hidden or deleted from the document using the NATSPEC Toolbar or the hidden text Hide and Delete functions of your word processing system. For additional information visit FAQs at
Optional style text
Text in this font (blue with a grey background) covers items specified less frequently. It is provided for incorporation into Normal style text where it is applicable to a project.
Related material located elsewhere in NATSPEC
If a listed worksection is not part of your subscription package and you wish to purchase it, contact NATSPEC.
Related material may be found in other worksections. See for example:
- 0131 Preliminaries for items to be supplied by the principal.
- 0221 Site preparation.
- 0222 Earthwork.
- 0224 Stormwater – site for site stormwater drainage including detention basins.
- 0241 Landscape – walling and edging for dam walls to custom built water features.
- 0250 Landscape – combined.
- 0251 Landscape – soils for membrane protection.
- 0252 Landscape - natural grass surfaces for grassed surfaces adjacent to water edge.
- 0253 Landscape – planting.
- 0255 Landscape – plant procurement.
- 0261 Landscape – furniture and fixtures for proprietary water features.
- 0275 Paving – mortar and adhesive bed for paving.
- 0310 Concrete – combined.
- 0331 Brick and block construction.
- 0332 Stone masonry.
- 0581 Signage for interpretive signage.
Cross references
Worksections that cross reference this worksection are:
- None.
Material not included in NATSPEC
Some projects may include items not covered by NATSPEC. For these you may need to create new text, or modify this text or a suitable worksection. For example:
- Swimming pools and large ponds, artificial beaches, ornamental rainforests with wetlands and grotto pools will require a detailed project specification.
- Specify detention basins in 0224 Stormwater – site.
Documenting this and related work
This worksection relies on fully detailed drawings of custom built water features including the following:
- General arrangement and location.
- Depth and freeboard (the minimum vertical distance between the design water depth and the overflow depth).
- Stormwater control facilities.
- Protective underlay and overlay materials.
- Waterproof membrane liner materials.
- Rock work, edging and paving.
- Water pattern.
- Pump and jet(s) arrangement.
- Lighting.
Pump equipment enclosure and sound attenuation.
Electrical and hydraulic requirements may be specified in 0802 Hydraulic design and install, 0814 Hydraulic pumps and 0702 Mechanical design and install .
1General
1.1Responsibilities
General
Requirement: Provide a complete membrane liner system together with landscaping elements, equipment and accessories necessary for an operating water feature, as documented.
As documented is defined in 0171 General requirements and refers to drawings, prompts in the worksection and SELECTION, Schedules.
Installation: Maintain the design intent for the pattern and flow of water.
Indicate the design intent on drawings.
Equipment: Maintain all equipment in full working order for the duration of the contract.
1.2Cross references
General
Requirement: Conform to the following:
-0171 General requirements.
0171 General requirements contains umbrella requirements for all building and services worksections.
List the worksections cross referenced by this worksection. 0171 General requirements references the 018 Common requirements subgroup of worksections. It is not necessary to repeat them here. However, you may also wish to direct the contractor to other worksections where there may be work that is closely associated with this work.
NATSPEC uses generic worksection titles, whether or not there are branded equivalents. If you use a branded worksection, change the cross reference here.
-0802 Hydraulic design and install.
-0814 Hydraulic pumps.
-0902 Electrical design and install.
1.3Interpretation
Definitions
General: For the purposes of this worksection the following definitions apply:
-Anchor trench: A trench excavated around the perimeter of a water feature into which the edges of the geotextile and sheet membrane liner are inserted and which diverts surface water runoff.
-Geotextile: A permeable synthetic fabric laid on soil, sand blinding, concrete or masonry substrates, serving to protect, separate, filter or drain.
-Membrane liner: The waterproof barrier between the water and the substrate and as follows:
.Seamless membrane liners: Low VOC emitting, single component, self curing liquid polymers applied directly to concrete or masonry substrates as a seamless film.
.Sheet membrane liners: Ultra-violet resistant, flexible sheet membranes installed on concrete, masonry or stable soil substrates and with seams lapped and sealed.
-Protective underlay and overlay: A layer of puncture resistant geotextile.
-Substrate: The surface to which a material or product is applied.
-Termination bar: A preformed strip for securing sheet membranes to wall substrates at their top termination line.
-Weir: The raised spillway of a waterfall or the opening on a skimmer outlet.
Edit the Definitions subclause to suit the project or delete if not required. List alphabetically.
1.4Submissions
Membrane quality
Documentation: Submit records of the following:
-Evidence of the manufacturer’s type tests for seaming methods.
-Weather conditions during installation and seaming.
-Code number of each joint including:
.Name of operator.
.Machines used.
.Date and time of seaming.
.Ambient temperature during installation.
Products
Documentation: Submit copies of product manufacturer’s:
-Product technical data sheets.
-Safety data sheets.
-Installation, operating and maintenance instructions.
-Instructions and procedures for the repair of the membrane liner.
Samples
Requirement: Submit 300 x 300mm samples of each type of geotextile and membrane liner.
Nominate other sample submissions such as paving units, planting pots and luminaires applicable to the project.
Tests
0171 General requirements covers tests in Definitions and calls for an inspection and testing plan under SUBMISSIONS, Tests.
Other tests: Submit results as follows:
-Substrate moisture content testing of concrete substrates.
-Water leakage testing of the membrane liner.
-Destructive testing on membrane seams.
Detail the tests required in PRODUCTS or EXECUTION, as appropriate, and list the submissions required here.
Warranties
Membrane liner: Submit details of the proposed warranty terms, form and period.
Requirement: Submit the following:
[complete/delete]
Describe the requirements of warranties in PRODUCTS or EXECUTION, as appropriate, and list the submissions required here.
1.5Inspection
Notice
Inspection: Give notice so that inspection may be made at the following:
-Substrate preparation completed.
-Membrane completed, before covering.
-Hydraulic and electrical services completed, before building in or covering.
Amend to suit the project, adding critical stage inspections as required.
Hold points, if required, should be inserted here.
2Products
2.1Membrane liner
General
Membrane liner: Provide a proprietary membrane liner certified as suitable for the external application and as documented.
Protective underlay and overlay: Provide a proprietary protective underlay and overlay certified as suitable for the external application and as documented.
-Geotextile: To AS3705.
The protective underlay and overlay should be made from non-woven polypropylene fibre with the following properties:
- Designed to resist deterioration over indefinite periods of time when buried.
- A minimum thickness of 2.5mm.
- A minimum weight of 280grams per square metre.
- Certified as needle free.
The underlay and overlay may also function as a slip sheet.
Accessories
Adhesives and sealants: Waterproof, flexible, mould-resistant and compatible with host materials.
Termination bar: Purpose made ultra-violet resistant high strength plastic or aluminium strips with a trapezoidal profile 28mm x 3mm and with pre-drilled holes for fixing.
2.2Weir
Proprietary items
Complete proprietary assemblies: Provide fixtures and fittings as complete assemblies, as documented.
Customised proprietary assemblies: Provide fixtures and fittings, as documented.
2.3Fountains and cascades
Proprietary items
Complete proprietary assemblies: Provide fixtures and fittings as complete assemblies, as documented.
Customised proprietary assemblies: Provide fixtures and fittings, as documented.
2.4Edging and Paving
Mortar bedded units
General: Provide edging and paving, as documented.
2.5Rock work
General
Refer to ROCK WORK in 0251 Landscape – soils or document here.
Location: [complete/delete]
Refer to drawings or describe here.
2.6Accessories
Submerged planting pots
General: Provide fixtures and fittings, as documented.
Location: [complete/delete]
Refer to project design details.
Submerged waterproof luminaires
General: Provide waterproof luminaires, as documented.
Location: [complete/delete]
3Execution
3.1Substrate preparation
Earthworks
Bulk earthworks: [complete/delete]
Refer to 0222 Earthwork and document there or here.
Obtain advice from the structural engineer on subgrade bearing capacity and maximum gradients to prevent membrane liner slippage.
Subgrade: Excavate to the required contours without sudden changes in level or direction.
Subbase: Lay selected material over the subgrade and as follows:
-Compact to 150mm minimum thickness.
-Remove all sharp objects, roots and stones over 50mm in size.
-Finish with sand blinding 50mm thick.
Anchor trench: Excavate to the perimeter of the water feature layout and as follows:
-Size: 600 x 600mm at the perimeter crest of the water feature.
Ground surface and services: Complete the following before installing underlay, overlay and membrane liner layers:
-Fill local depressions and remove water.
-Install hydraulic and electrical services.
Concrete and masonry substrates
Preparation: Prepare substrates as follows:
-Chamfers and fillets: Provide as follows:
.At substrate external corners: Chamfered edges 20 x 20mm.
.At substrate internal corners: 45° angled, cement mortar fillets 50 x 50mm.
-Control joints: Prepare all substrate joints to suit the membrane liner installation.
-Fill all cracks in substrates wider than 1.5mm with a filler compatible with the membrane liner.
-Fill voids and hollows in concrete substrates with a concrete mix not stronger than the substrate.
-Remove all projections.
-Cut mortar joints flush.
-Remove deleterious and loose material.
-Leave the surface smooth, free of contaminates, clean and dust free.
Concrete substrates: Cure for more than 21 days.
Moisture content
Requirement: Verify that the moisture content of the substrate is compatible with the water vapour transmission rate of the membrane system by testing to AS1884 Appendix A.
Test type: Select from the following:
-Hygrometer test: Seal a hygrometer to the substrate for at least 16 hours and measure the relative humidity of the air between the instrument and the slab.
Refer to NATSPECTECHnoteDES008 on the preparation of concrete substrates. Refer also to CCAADataSheetMoistureinconcreteandmoisture-sensitivefinishesandcoatings.
Falls
Substrates, drains and sumps: >1.5%.
Consult the membrane supplier to determine a fall that minimises ponding at lapped seams and adjust the amount of fall, if required.
3.2Seamless membrane liner
Delete this clause if a sheet membrane liner is documented.
Environmental conditions
Liquid membrane: Install to the manufacturer’s recommendations including the following:
-Apply within the recommended range of ambient and surface temperatures.
-Adjust curing period for successive coats to suit prevailing weather conditions.
-Protect from rain after installation.
-Protect from excessive sun exposure before water filling.
Application
Coating system: Apply the required number of coats for the selected seamless membrane liner.
Surface defects: Inspect the final surface coating when touch dry for pinholes, voids and thin spots.
Reinstatement: Repair faulty or damaged work. Replace the whole affected area if the work cannot be repaired satisfactorily.
Protective overlay: Spread geotextile layer, as follows:
-Laying: Spread evenly without wrinkles and free of tension.
-Lap widths: To the manufacturer’s recommendations.
Customise as appropriate for the project and design of the water feature details.
3.3Sheet membrane liner
Delete this clause if a seamless membrane liner is documented.
Environmental conditions
Sheet membrane: Install to the manufacturer’s recommendations including the following:
-Suspend laying and seaming operations in wet weather or during high winds.
-Do not leave the membrane liner uncovered overnight.
Installation
Protective underlay: Spread geotextile layer to the extent of the perimeter anchor trench as follows:
-Laying: Spread evenly without wrinkles and free of tension.
-Lap widths and joint types: To the manufacturer’s recommendations.
Membrane liner: Spread membrane liner to the extent of the perimeter anchor trench as follows:
-Laying: Spread evenly without wrinkles and free of tension. Avoid pulling out all slack in the lining.
-Lap widths and joint types: To the manufacturer’s recommendations.
-Water inlet locations: Provide a double membrane liner layer, lapped and sealed.
-Penetrations: Seal services penetrations in conformance with membrane manufacturer’s recommendations.
-Reinstatement: Repair faulty or damaged work. Replace the whole affected area if the work cannot be repaired satisfactorily.
Protective overlay: Spread geotextile layer to the extent of the perimeter anchor trench as follows:
-Laying: Spread evenly without wrinkles and free of tension.
-Lap widths: To the manufacturer’s recommendations.
Anchor trench
Anchoring of protective underlay, overlay and membrane liner:
-Insert free edges of protective underlay and membrane liner to inner wall of anchor trench and terminate at the trench floor. Make sure top of the membrane liner is a minimum 150mm below finished ground or paving level.
-Insert free edges of protective overlay in the anchor trench, covering the entire trench floor and extend up the trench outer wall and with sufficient excess for edge return.
Anchor trench backfill: Coarse aggregate of crushed rock with a nominal size greater than 5mm. Backfill to a minimum 150mm below finished ground or paving level. Return edges of protective overlay to wrap over top of backfill.
Termination bar
Installation: Fix bars in the longest available lengths over the protective underlay and membrane liner as follows:
-Directly to hard, smooth wall surfaces with the narrow face of the trapezoidal bar against the wall.
-Fill the top trough on the bar with approved sealant.
-Provide a 6mm gap between ends of adjacent bars.
-If field cutting is required, remove any burs from the bar and progressively clean up shavings.
3.4Membrane protection
General
Soil: [complete/delete]
Refer to 0251 Landscape – soils and document there or here.
Concrete: [complete/delete]
Refer to 0310 Concrete – combined and document there or here.
Filling
General: Fill with water as soon as possible after installation is complete, at a rate that will not cause damage or disturbance to protective material, growing medium, or plants.
3.5Weir
Structure
Retaining walls: [complete/delete]
Refer to 0241 Landscape – walling and edging and document there or here.
Masonry spillways
Materials and execution: [complete/delete]
Refer to 0331 Brick and block construction or 0332 Stone masonry and document there or here.
Metal spillways
Materials and execution: [complete/delete]
3.6Fountains and cascades
Proprietary items
Installation: [complete/delete]
Document here or refer to fountain and cascade manufacturer’s technical information
Reinstatement: Repair damage to underlay, membrane liner and overlay, caused by fountain and cascade installation, to the membrane manufacturer’s recommendations.
3.7Edging and Paving
Mortar bedded units
Materials and execution: [complete/delete]
Refer to 0275 Paving – mortar and adhesive bed and document there or here.
3.8Rock work
Rock work assembly
Placement: Place rocks in water areas as follows:
-Set on a layer of geotextile and remove visible surplus material.
-Make sure there is no defacement of the natural weathered surface.
Placement pattern: Place rocks to achieve the following:
Water movement requirement: [complete/delete]
Water movement requirement: Describe the designed performance requirement e.g. to flow between rocks, to flow as a sheet over the rocks or to splash around the rocks.
Rock work design: [complete/delete]
Refer to drawings or document here.
3.9Submerged pots and Luminaires
Submerged planting pots
Placement: Set on a layer of geotextile and remove visible surplus material.
Submerged waterproof luminaires
Placement: Secure waterproof luminaire fittings to stable rocks or pots, as documented.
3.10Water leakage test
Testing
General: Before the installation of any overlaying elements carry out a water leakage test of the membrane liner.
Testing procedure: Carry out testing as follows:
-Record all activities of the test and submit test results.
-For evaporation standardisation, provide an open topped container not less than 1000 x 1000mm in area and 300mm deep. Place the container in the immediate vicinity of the water feature being tested. Fill the container with water to a marked depth of 200mm. Label and protect the standardising container to prevent disturbance of the water.
-Fill the membrane liner with water to the design water depth at a rate not exceeding 100mm depth per hour.
-Allow a minimum period of 7 calendar days to elapse.
-If water loss is such as to defeat the intent of the test, record the results, carry out repairs and repeat the test procedure.
-If there is no significant difference between the water level of the membrane liner and the standardising container, up to a maximum of 3mm depth, the membrane liner is water retaining.
3.11Warranty
Requirement
Membrane liner: Provide the warranty.
4Selections
Schedules are a way of documenting a selection of proprietary or generic products or systems by their properties. Indicate their locations here and/or on the drawings. Refer to NATSPECTECHnoteGEN024 for guidance on using and editing schedules.
4.1Proprietary items
Seamless membrane liner
Product: [complete/delete]
Thickness: [complete/delete]
Total VOC’s: [complete/delete]
Sheet membrane liner
Product: [complete/delete]
Thickness: [complete/delete]
Select type of sheet membrane liner, e.g. butyl rubber, EPDM (ethylene propylene diene monomer) or PVC.
Membrane protection
Type: [complete/delete]
Select type of membrane protection, e.g. soil or concrete bed. Nominate properties to describe the bed.