Questions & answers

A geomembrane is a thin, low-permeability synthetic sheet used as a barrier to contain liquids or gases in ponds, reservoirs, canals, landfills and containment areas. HDPE (high-density polyethylene) is the most widely used type. The sheets are welded together on site into one continuous liner, and the welds are tested for leaks.

Yes. Insulation (عزل) with geomembrane is our core work: we supply, install, weld and test HDPE geomembranes that line and waterproof ponds, water reservoirs, canals, landfills and containment areas across Saudi Arabia.

MWAN's Standards & Technical Guidelines for the Design, Construction and Operation of Landfills (TG-WM-05 (2), 1 November 2024) set a minimum geomembrane for each landfill category: • Category 1 (hazardous waste): at least 2.5 mm HDPE, or a double liner with leak detection (2.0 mm HDPE, a geocomposite drainage layer and a second 2.0 mm HDPE). • Category 2 (non-hazardous waste): at least 1.5 mm HDPE. • Category 3 (inert waste): no geomembrane required, depending on the liner system used. The final thickness follows the approved design and can be increased based on the project's risk assessment.

Not by default. MWAN's landfill guideline notes that a leak location survey after cover placement is not mandatory, but the facility owner or the authorities may require one on high-risk sites. Where a project specifies a survey, Optimum Techniques for Contracting coordinates it with specialist survey providers.

A Construction Quality Assurance (CQA) plan sets out how the liner is supplied, installed, tested and documented. Under MWAN's guidelines, the geomembrane part covers material specifications; delivery, storage and handling; conformance testing; panel deployment; trial and field seam welding; non-destructive and destructive testing; repairs; and protection and backfilling. An independent third-party engineer supervises CQA throughout construction. A final CQA certification report records all test results, including failed tests with their corrective actions and retests, along with test location drawings, as-built drawings, daily site records and non-conformance records.

For most exposed evaporation ponds, 1.5 mm HDPE is the practical minimum. 2.0 mm is common where the pond holds hazardous brine, where desludging equipment will work on the liner, or where a long design life is required. Higher-risk applications often use a double liner: two HDPE layers with a leak detection layer between them, draining to a monitoring sump. In Saudi heat, thickness is only part of the answer. The material should meet GRI-GM13 for carbon black and antioxidant content, and the installation must allow for thermal movement, because exposed black HDPE can exceed 70 °C in summer.

During installation, seams are tested non-destructively and destructively. Non-destructive methods include vacuum box testing of extrusion welds and details, spark testing, and air-pressure testing of double-track fusion seams; ASTM D4437 describes non-destructive seam testing practice. Destructive testing means cutting samples and testing them in peel and shear with a tensiometer. After installation, an electrical leak location survey can scan the whole liner and pinpoint holes that seam testing cannot find, such as punctures from tools or stones. Optimum Techniques for Contracting tests with vacuum box and spark testing and runs peel and shear tests with an on-site tensiometer. Where a project specifies a leak location survey, we coordinate it with specialist providers.

There is no single price per square metre. These are the main cost drivers: • liner thickness, and whether it is smooth or textured • total area, since mobilisation is spread over more square metres on large jobs • geometry: slopes, corners, pipe penetrations and structures all add welding and detailing time • the condition of the subgrade and how much preparation it needs • extra layers, such as protection geotextile or a second liner with leak detection • QA/QC scope, including third-party testing and any leak location survey • site location, access and working hours, including summer restrictions. To give a firm price, a contractor needs the approximate area, the liner specification, drawings if available, and the site location.

For most ponds in Saudi Arabia, HDPE. Ordinary plastic sheet (often called nylon, نايلون) is a thin film that is not made to any geomembrane standard, and its joints are only overlapped or taped. PVC geomembrane is flexible, but it contains roughly 25–35% plasticiser and its durability depends heavily on the formulation: in the Geosynthetic Institute's exposure tests, one North American PVC reached its half-life in about 18 years, while a European formulation was still going after 32. Manufacturers' chemical-resistance tables also rate PVC as severely affected by crude oil. HDPE to GRI-GM13 contains no plasticiser, has 2–3% carbon black for UV resistance, resists salt and most oils, and is predicted to last more than 36 years exposed in a dry, arid climate. Its seams are heat-welded and tested.

Farm and fish ponds commonly use HDPE between 0.75 mm, the thinnest covered by GRI-GM13, and 1.5 mm. Choose by pond size, the ground (stony ground needs thicker sheet or a protection geotextile), whether the liner is exposed to the sun, and how the pond will be cleaned. Thicker sheet has higher puncture and tear resistance but costs more per square metre. For fish and shrimp, use a liner made from virgin resin that is suitable for contact with water and fish.

Yes. Manufacturers' chemical-resistance tables rate HDPE as little or not affected by salt water and by sodium, calcium and magnesium chloride solutions, so brine is not what limits the liner's life. Sun, heat and damage during cleaning are. For exposed brine, salt and RO reject ponds, use HDPE to GRI-GM13, typically 1.5 mm or thicker for industrial ponds, and plan protected access for salt and sludge removal.

Generally yes. Manufacturers' chemical-resistance tables rate HDPE as little or not affected by diesel and lubricating oil, and expect only a minor effect from crude oil. Light fuels such as gasoline and kerosene have a minor to moderate effect, concentrated aromatic solvents such as xylene a severe one, and higher temperatures increase the effect. Where the fluid is unusual or hot, test the liner in the actual fluid using US EPA Method 9090, the standard compatibility test for wastes and membrane liners.

Yes. We supply HDPE geomembrane rolls on their own, from our trusted suppliers, for contractors and owners who install with their own welding teams. Tell us the thickness, whether you need smooth or textured sheet, and the quantity. We can also supply and install, with welding and testing by our own crew.

Yes. We supply and install modular hexagonal floating covers for water reservoirs, irrigation ponds, wastewater, industrial and oil and gas ponds, to reduce evaporation, odour and emissions, algae growth and bird access. We also supply covers on their own. Tell us the pond size, the liquid and what the cover is for, and we will quote.

Yes. We supply and install HDPE geomembrane liners for water ponds and reservoirs, farm and irrigation ponds, fish ponds and shrimp ponds, on projects of all sizes, with heat-welded seams that are tested on site. We also supply HDPE rolls without installation.

No. A tarpaulin is a cover sheet, made from coated fabric or from woven polyethylene strips laminated with plastic sheet, to protect goods and loads from wind, rain and sun. It is not made or tested to a geomembrane standard. The liner for a permanent water, fish or shrimp pond is an HDPE geomembrane to GRI-GM13: at least 0.75 mm thick, with 2–3% carbon black for UV resistance and heat-welded seams tested on site. Many people still call a pond liner a شراع or طربال; what we supply and install is HDPE geomembrane.

Use textured HDPE where friction matters: on side slopes that will carry soil cover, drainage material or waste, and at interfaces with geotextiles where sliding could occur. Smooth HDPE is standard for pond floors, exposed slopes without cover and most water applications. Textured liner costs more and is harder to clean, so it is usually specified only where the stability analysis requires it. A common result is textured liner on the slopes and smooth liner on the floor.

GRI-GM13 is the Geosynthetic Institute's standard specification for smooth and textured HDPE geomembranes. It sets minimum values and test frequencies for properties such as thickness, density, tensile strength, tear and puncture resistance, carbon black content and dispersion, and oxidative induction time (antioxidant content). Referencing GM13, and asking for the manufacturer's certificates, is the simplest way to get a liner that will last in exposed Saudi conditions rather than a cheaper sheet that only looks the same.

At a minimum, the installer should hand over: • the approved method statement and inspection & test plan • manufacturer certificates for the material • panel layout and deployment records • trial weld and seam records • non-destructive and destructive test results, including any failed tests with their corrective actions and retests • a repair log • test-location records and as-built data. For MWAN-regulated landfills, these records feed the project's CQA certification report.

A covered HDPE liner, under soil, waste or water, is protected from UV and heat and can last many decades. An exposed liner ages faster. Its service life depends mainly on UV intensity, temperature and the antioxidant package in the material. In the Kingdom's climate, specify material that meets GRI-GM13 and use 1.5 mm or thicker for exposed industrial ponds. Inspect exposed liners periodically so that small damage is repaired before it spreads. For reference, research by the Geosynthetic Institute (GRI White Paper #6) predicts a half-life of about 446 years for a covered HDPE liner made to GRI-GM13 at 20 °C, falling to about 69 years at 40 °C, and more than 36 years for exposed GRI-GM13 HDPE in a dry, arid climate, with that testing still ongoing. These are predictions for properly made material, not a guarantee.

Yes. We repair HDPE liners with extrusion-welded patches, test every repair and document it. Aged, exposed HDPE needs its surface prepared before welding, and a trial weld on the old material shows whether a reliable repair is possible. We guarantee our workmanship and support our clients after handover.

Yes. We take on projects of all sizes, including farm irrigation ponds and water ponds. Small projects get the same trial welds, testing and records as large ones.

Yes. We work both as a direct contractor and as a specialist lining subcontractor to main contractors and EPC companies. For civil scope, such as earthworks, subgrade and cement-stabilised sand cover, we work with a partner civil contractor.

Heat affects both the crew and the liner. Outdoor work in direct sun is prohibited from 12:00 to 15:00 between 15 June and 15 September. Hot sheet temperatures also narrow the welding window and increase wrinkles. Good practice is to plan deployment and welding around the cooler hours, deploy only what can be welded and ballasted the same day, and place cover when the liner has contracted in the early morning. Summer projects are entirely feasible; they just need a realistic programme.

We are based in Dammam, in the Eastern Province, and serve all regions of Saudi Arabia. We have delivered projects in Dammam, Jubail, Riyadh and Jazan.