How to Align Scope Between Supply Quotes and Installation Quotes for Tensile Membrane Structures — Avoiding Missed Items

When you receive two quotes for a tensile membrane structure project — one marked "supply only" and one marked "supply and installation" — the prices may differ significantly. Before comparing the numbers, align what each quote includes and excludes. A supply quote typically covers only what is completed in the factory; an installation quote covers what happens after delivery to site. Missed items usually fall in the gap between the two quotes.

What Should a Supply Quote Include? Item-by-Item Checklist

A complete supply quote for custom fabrication should state clearly whether the following items are included:

Checklist item	What to confirm
Steel structure	Whether members are prefabricated to finished condition at the factory, and whether anti-corrosion surface treatment is included
Membrane material	Membrane type and grade, and whether cutting and patterning (fabrication of the membrane panels) is included
Connecting hardware	Whether clamp plates, bolts, tensioning fittings and similar components are supplied as a matched set, and whether their specifications match the design drawings

Two points deserve extra attention when reviewing:

1. Connecting hardware is easy to miss. If procured separately, fittings may not match the hole positions in the membrane panels.
2. How the warranty is written. The proper practice is itemized warranties — separate terms for membrane fabric, steel structure and other components — all written into the contract, with no verbal-only promises. If a quote simply states "X-year warranty," ask whether this covers the whole system or applies item by item.

Foundations, Transport and Lifting: List Them Separately

These three items are the most commonly missed. Ask for each to appear as a separate line in the quote rather than being casually "bundled in" by either the supplier or the installer:

1. Foundations: Clarify who designs, who constructs and who inspects and accepts them. Reworking foundations has occurred in real projects; the cost of rework far exceeds the effort of defining the responsibility boundary in advance.
2. Transport: Tensile membrane structure members are lightweight, so logistics is a limited share of project cost. Confirm whether the quote includes freight to site and who is responsible for unloading.
3. Lifting: Different spans require different lifting equipment, and costs vary widely. State who arranges and rents lifting machinery, how the cost is calculated, and who provides the site working conditions.

Once these three items are listed separately, the boundary between the supply quote and the installation quote has essentially no gray areas left.

What Does the Buyer Take On Under the Installation Scope?

If you choose factory supply and arrange a local crew for installation, your responsibilities typically include:

• Foundation construction and acceptance;
• Organizing site lifting machinery and working areas;
• Controlling installation quality — once members arrive on site, the fabricator's team is not there, and correct connection details must be judged by you or your project engineer.

This is why the industry often says installation matters as much as fabrication. If a single party covers design, fabrication and installation, the situation is simpler: members arrive as finished products with no on-site fabrication, the working crew follows one unified process standard, and key connection points are supervised by the fabricator's technical staff. Because supply and installation responsibility sit with the same party, disputes like "the steel fabricator blames the membrane, the membrane supplier blames the installation" are avoided.

Design responsibility and supply boundaries should always be agreed explicitly between you (the buyer) and your project engineer before contracting.

How to Compare Different Quotes on the Same Scope

The method is simple: build one comparison table using a single scope baseline, and mark each quote "included / not included" against every line below:

1. Steel structure (including surface treatment)
2. Membrane material and cutting/patterning
3. Connecting hardware
4. Foundation design and construction
5. Transport and unloading
6. Lifting machinery and associated costs
7. Installation labor and process standard
8. Itemized warranty terms (written into the contract)

Once both sides use the same scope, the source of any price difference is immediately visible. Add the cost of "not included" items yourself before comparing totals — do not compare headline numbers only.

One further note for overseas procurement: supply quotes for projects outside the fabricator's own region generally cover only the pre-shipment scope. Local installation is organized by the buyer, so state this clearly in your RFQ (Request for Quotation — your formal inquiry listing scope, drawings and requirements). Requests should include your project location, intended use, dimensions and available drawings, plus which services you want quoted.

FAQ

Q: If the supply quote does not mention foundations, can I ignore them? No. Foundations are site works. Most supply quotes exclude them by default; they must be contracted separately with clearly assigned acceptance responsibility.

Q: If I hire a local installation crew, where are the main risks? Membrane tensioning is an experienced trade. Incorrect connection details affect membrane stress distribution and service life. If your local crew has no tensile membrane structure experience, at minimum request technical guidance documentation from the supplier — and confirm in advance what guidance the supplier will actually provide.

Q: Is a verbal "ten-year warranty" reliable? Insist on written terms. Specify separate warranty arrangements and periods for membrane fabric, steel structure and other components in the contract. Verbal promises are difficult to enforce at settlement or repair stage.

Next step: Prepare your project use, dimensions or drawings, and the service scope you wish to commission (supply, installation, or a defined supply scope with local installation). Share these details together with your project location and drawings through our contact page (/en/contact/) so we can review the scope and prepare an itemized quotation on a consistent basis.

Note: This article is a draft translation/adaptation pending editorial review.