A 122 metre square roof in poor condition that was still structurally capable
A single industrial roof measuring 122 metres by 122 metres was appraised for solar PV. The covering was found in poor condition for continued industrial use, and the structure beneath it was still capable of carrying the proposed array.
What the project needed.
This is the case that shows why condition and capacity are two questions rather than one. The roof is a single flat-pitch span of 122 metres by 122 metres, purlins at 2.935 metre centres on 7.45 metre bays, at 8.596 metres high. The majority of the covering was assessed as being in poor condition for the building's continued industrial use. The structural framework beneath it was assessed as capable of carrying the anticipated loading from the proposed installation. Both findings are correct and they point in different directions.
Work carried out
- Non-intrusive visual survey of the property, inside and out
- Structural roof loading appraisal of the full roof area
- Roof geometry, span, height, purlin and bay spacing recorded
- Dead load built from the actual specified roof make-up
- Site specific wind loading and snow loading assessment
- Justification of panels for gravity and uplift loading
- Covering condition assessed and reported separately from capacity
- Aerial drone survey of the roof area
What global ardour, preston actually involves.
A covering in poor condition and a frame with capacity is a common combination and an uncomfortable one to report, because the client wants a single answer and the honest response is two. Reporting only the capacity would let an array go onto a covering that needs attention. Reporting only the condition would imply strengthening that the frame does not need.
The scale is what makes it consequential. At 122 metres square the roof is close to fifteen thousand square metres in one plane, so a covering issue is not a localised repair and an installation programme committed on the wrong assumption is expensive to unwind.
Dead load was built from the specified make-up: 0.46 kN/m² for the existing steel sheets and EPDM and 0.15 for the purlins, giving 0.61 kN/m² total, against an imposed roof loading of 0.60 kN/m² to BS 6399 Part 3 and Eurocode 1.
Purlins at 2.935 metre centres are widely spaced by the standards of this building type, which matters for how an array is fixed and where its load actually lands. Spacing that wide is measured rather than assumed, because a mounting system designed for closer centres has nowhere to go.
On site.
A single roof plane of 122 by 122 metres, surveyed from the air.
Global Ardour, Preston
Structural roof loading appraisal with wind and snow loading appendices and aerial drone coverage, issued alongside a separate roof condition report.
Related work and services.
Tell us what you are building.
Send the drawings or describe the project. We confirm scope, deliverables and a realistic timescale.
Start a project