Tensile Membrane Structure Manufacturer
Pre-stressed architectural-fabric structures — the membrane is the primary surface, form-found into a doubly-curved shape and locked under tension so it behaves as a stiff roof. In PVC, PVDF, PTFE or ETFE, engineered and installed by Ekra Decor since 1998.
- The membrane is the structure, not a cladding
- Form-found doubly-curved surfaces
- PVC, PVDF, PTFE & ETFE
- Engineered to IS 875, IS 800 & IS 456
Engineering Trusted by India’s Leading Names
28+ years delivering tensile structures for corporate campuses, industrial groups, and institutional developments — built with fabric technology from the world’s leading membrane manufacturers.
TATA Motors
L&T
Reliance
Adani
Mahindra
Godrej
DLF
ITC Ltd
Maruti Suzuki
GMR Group
JSW Steel
Prestige Group
Sobha
Siemens
Tata Chemicals
Tata Tele Business Services
Power Grid Corporation
Emaar MGF
National Law University Delhi
UPES Dehradun
Vasant Valley School
Aditya Birla Group
Amity University
Vikram Solar
Tractors India
Mazda Colours
Millennium Structurals
Sehwag International School
BSBK Pvt. Ltd.
17 Miles Hotel
Rich Harvest School
The Imperial New Delhi
Moore Constructions
Mehra Construction
Ramprastha
Minda NexGenTech (UNO Minda)
Yashmay Public School
Gyan Mandir Foundation
Omega Developers
SPEC
Serge Ferrari
Mehler
Heytex
Versaid
Pait
How a tensile membrane structure holds its shape
A tensile membrane structure gets its stiffness from pre-stress, not from thickness. When the membrane is installed it is stretched in two directions at once and locked at that tension. Every point on the fabric is then held taut, so the surface behaves like a rigid shell even though it is only a millimetre or two thick.
Why the surface has to be double-curved
A flat, evenly tensioned membrane is unstable — any load pushes it out of plane and it flutters or ponds. A stable membrane is anticlastic: it curves upward in one direction and downward in the perpendicular direction. The downward curve carries rain and live load into the cables; the upward curve resists wind uplift. The two work against each other and keep the fabric tight in every wind.
Form-finding comes before drawing
You cannot simply draw a membrane shape and build it — an arbitrary surface will have uneven stresses and will wrinkle. Ekra Decor form-finds every structure in ixCube and ANSYS: the software starts from the support points and solves for the equilibrium shape in which the fabric stress is uniform. Only then is the 3D surface unrolled into flat panels, with an allowance for the fabric stretching back out under tension.
Patterning and compensation
The flat panels are cut slightly smaller than their final size — typically 1 to 4 percent, depending on the fabric — so that when they are tensioned on site they stretch to exactly the design geometry. Get the compensation wrong and the membrane is either slack (ponding, flutter) or over-stressed at the corners.
Tensioning on site
The frame and cables go up first. The membrane is then lifted, clamped along its edges and drawn out to its design pre-stress in a set sequence, usually corner-to-corner and then along the ridges, so the load builds evenly. A correctly tensioned membrane looks crisp, sheds water cleanly and needs no attention for years; an under-tensioned one shows creases and moves in the wind.
The membrane itself is a coated architectural fabric — PVC-polyester, PVDF or PTFE-glass. For the wider picture of how tensile structures work, see our tensile structure page, or send your site details for a specific design.
The tensile membrane, in brief
In a membrane structure the fabric is not a covering on a frame — it is the load-carrying surface, held rigid by its own tension.
Pre-stress
A locked-in tension applied at installation — it is what makes a thin fabric behave as a stiff surface.
Anticlastic curvature
The surface curves up one way and down the other; one curvature carries downward load, the other carries uplift.
Form-finding
The specific 3D shape in which the pre-stress is balanced is solved by software, then unrolled into flat cutting patterns.
Cables & steel
Edge, ridge and valley cables collect the membrane forces and deliver them to a few points on the steel.
This page covers the topic in brief. For the full technical reference — how tensile structures work, all the types, form-finding, membrane materials, design codes and construction process — see the tensile structure guide.
What is specified
A membrane structure is specified by its form, its membrane grade and its cable and steel system — all of which come out of the form-finding and load analysis.
| Element | Options |
|---|---|
| Form | Conical, hypar, barrel vault, ridge-and-valley, dome, sail, or a free-form surface |
| Membrane | PVC-coated polyester, PVDF-lacquered PVC, PTFE-coated glass, or ETFE film |
| Cables | Edge, ridge, valley and stay cables, with a factor of safety of about 1:2.2–1:3 on breaking load |
| Membrane FoS | About 1:5–1:7 on the minimum tensile strength, normal practice |
| Frame | Masts, arches or columns in galvanised steel, designed to IS 800 |
| Foundations | Designed to IS 456, sized for uplift and overturning |
| Scope | Form-finding, structural design, patterning, fabrication, installation and tensioning — one in-house team |
Membrane figures — life, translucency, fire class — are manufacturer values for the material type; see the membrane materials page.
Membrane options
The membrane is chosen for the project — PVC or PVDF for most work, PTFE-glass for permanence or a fire class, ETFE film where daylight is critical. The membrane materials page compares all four.
PVC-coated polyester
The most economical choice and the widest colour range; blocks the rain, hail and almost all UV. PVC fabric →
PVDF-lacquered PVC
The same base with a tougher top-coat that stays cleaner under dust and pollution. PVDF fabric →
PTFE-coated glass
Non-combustible and near self-cleaning, with the longest service life. PTFE fabric →
A full comparison of the fabrics — translucency, fire class, typical life — is on the membrane materials page.
How it is engineered and built
The governing load
The membrane is form-found so its pre-stress is balanced in every direction, then loaded with dead, pre-stress, wind, rain and any snow or seismic case. Peak membrane and cable stresses are extracted and the steel and foundations designed to IS 800 and IS 456, with wind to IS 875 Part 3.
Why the shape is found, not drawn
A membrane roof has one stable geometry — the one where its tension holds it rigid. Getting that wrong cannot be fixed with more steel.
Steel & foundations to code
The frame is designed to IS 800 and the footings to IS 456, checked for uplift and overturning. Galvanising to IS 4759 / IS 2629 for corrosion protection.
Built off-site, raised fast
Steel is cut, welded and galvanised in the workshop and the membrane is cut and welded into panels, while the footings are cast on site. On-site work is then quick and low-disruption.
One accountable team
Survey, 3D design, fabrication, installation and tensioning are all Ekra Decor’s own team, with a handover pack of drawings, load report, stability certificate and material certificates.
What drives the cost
Cost is not a fixed rate per square foot — two structures of the same size can differ widely. The main factors:
A membrane structure is priced from its own design. Send the brief and the site for a concept and an itemised quote; see the cost guide.
Looking after the structure
- Cleaning — a periodic wash; PVDF and PTFE surfaces largely self-clean in rain.
- Membrane & seams — check for abrasion, coating wear and seam lifting at the corners.
- Cable tension — a first re-tension after the initial season, then a periodic check.
- Steel & connections — inspect the galvanising and the connections at ground level.
- Drainage — clear the gutters, valleys and outlets before the monsoon.
Membrane structures we’ve built
Each project is documented with site photographs and recorded scope.
Retail · Courtyard roofVasant Square MallVasant Kunj, New Delhi
Industrial · Single-span roofDesai ConstructionValsad, Gujarat
Transit · Walkway canopyIGI Airport, Terminal 2New Delhi
Industrial · Store-shed roofVikram SolarKolkata, West Bengal
Public · Courtyard shadeHazratbal DargahSrinagar, J&K
Public · Atrium skylightsGuwahati Tensile StructureGuwahati, Assam
Tensile membrane structure FAQ
The questions people ask about pre-stressed membrane structures.
A structure in which a pre-stressed architectural fabric is the primary load-carrying surface, not a cladding on a frame. The membrane is form-found into a doubly-curved shape and held rigid by its own tension.
An engineered coated fabric — PVC-coated polyester, PVDF-lacquered PVC, or PTFE-coated glass fibre — or ETFE film. Each is a woven or extruded base locked inside a protective coating.
Solving for the specific 3D shape in which the membrane's pre-stress is balanced in every direction — the shape where its own tension holds it rigid. It is done with structural software; a membrane roof cannot be designed as a flat plane.
A new membrane creeps slightly in its first months and settles; a designed-in re-tensioning, usually once after the first season, brings it back to full pre-stress.
A membrane factor of safety of about 1:5 to 1:7 on the minimum tensile strength, and a cable factor of safety of about 1:2.2 to 1:3 on the breaking load, is normal practice.
It depends on the brief — PVC for economy, PVDF for a longer-lasting finish, PTFE for permanence and fire class, ETFE for maximum daylight. See the membrane materials page.
There is no rate card — it is priced from its own design. Send the brief and the site for a concept and an itemised quote.
Send us the brief and the site
You get a form-finding direction, a membrane recommendation and an itemised quote.
Let’s Build Your Structure
Speak directly with our structural engineering team to discuss your project dimensions, material options, or to schedule a free on-site technical inspection across India.
Direct Phone & WhatsApp Hotlines
+91 98102 37952 (Delhi HQ) / +91 93159 45187 (Bangalore) / +91 82879 92289 (Engineering)
Official Email Address
Delhi Factory & Administrative HQ
No. 367 Badam Singh Market, Rangpuri, Near Shiv Murti, NH-8, New Delhi 110037
Bangalore Regional Office
93/5, Kada Agrahara Village, Dodda Gubbi Post, Bangalore, Karnataka - 560077, India
Chattarpur Office
House No. 488, 3rd Floor, Khasra No. 60, 100 Futa Road, Opposite Delhi Jal Board, Near Diwan Bajaj Showroom, Chattarpur Pahari, New Delhi - 110074, India
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