THE GUIDE / care
Replacing a polytunnel cover: prepare a supplier request (UK)
Organise the frame records, replacement parts and open questions before asking for a written quotation.
Before requesting a replacement, gather the records that identify the tunnel and the parts you want quoted. Ask the maker or supplier to name the frame and documents they used, list what the proposed quote includes, and confirm its dimensions in writing.
The cover calculator estimates a curved roof-sheet shape from a simplified half-ellipse. It is a geometry illustration, not a maker's formula or an order size. Do not order from its result.
Gather the frame records
Find the original order confirmation, invoice, assembly paperwork, parts list or correspondence. Copy the maker, model or range, size and frame or order reference as written. Note any known alterations and when they were made; mark anything uncertain as unknown.
Ask for a dimensioned drawing or parts document for that exact frame and size. Record its title, revision or date, and page number. If you are unsure whether it describes your tunnel, include that as an open question instead of relying on a catalogue image or resemblance to another model.
List the parts to include in the request
Write down what you want the supplier to quote. Keep each roof, end, door covering or other named section on a separate line. This is a scope checklist; it does not assume every tunnel has separate pieces.
| Part to discuss | What to record | What to ask the supplier |
|---|---|---|
| Roof sheet | Number of frames and whether the roof is in scope | What area the quoted sheet is intended to cover |
| End panels | Which end or ends, and how many frames | Whether each end is separate, included with another part or outside the quote |
| Door coverings | Which opening or openings, and how many frames | Whether these are included, separate or outside the quote |
| Other sections | Name each part from the drawing or paperwork | What the quoted item covers and what remains excluded |
Ask the supplier to list inclusions and exclusions against those lines. If only the roof is needed, say so plainly and ask whether the proposed scope depends on any other part.
Share dimensions with their source
Copy dimensions from the maker's drawing or from a measuring procedure the supplier has provided. Keep each value with its units and document reference. If you have no confirmed measurement, write “not confirmed” and ask what information they need. This worksheet gives no measuring procedure.
The fixing-system name can also be copied from the maker's paperwork, along with its document reference. If it is missing or unclear, ask the supplier to identify the relevant system for the frame. Do not infer compatibility from appearance or a familiar-sounding term; ask them to state which model and document they matched to the proposed parts.
Example of the calculator's geometry
For a deliberately hypothetical input, use a 3 m width, 6 m length and 1.5 m hoop height. The half-ellipse calculation gives an arc of about 4.71 m. Add a user-chosen 0.5 m allowance on each side, and the estimated width is about 5.71 m. Applying the same chosen allowance at both length ends gives 7 m.
These values illustrate the calculator's arithmetic only. The example allowance is not a recommendation, and the half-ellipse is not a verified description of any particular frame. The result does not identify compatible material, profile, fixings or order dimensions. Confirm all proposed parts and measurements with the supplier before ordering.
Ask for a written confirmation
Send the frame reference, drawing details, parts list, fixing-system wording and any confirmed dimensions together. Ask the supplier to reply with:
- the model and drawing used to identify the frame;
- the proposed dimensions and units for each part;
- the named fixing system they have matched;
- what the quotation includes and excludes; and
- any point they could not verify.
If a reply leaves something unclear, ask a specific follow-up before ordering. For example: “Please confirm whether this quotation includes both end panels for model [reference], and list the proposed dimensions for each sheet.” Fill the placeholder from your records rather than guessing.
Keep the reply with the original frame documents. The worksheet prepares a request; the supplier's model-specific confirmation is still needed to establish what the quotation covers. For the calculator's assumptions, see its method notes. The site's comparison method explains how unverified details are left open rather than filled by assumption.