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Sandwich Panel Accessories Calculator (Screws, Sealant)

Estimate screws, sealant tubes, corner profiles, and J-trim metres needed to install a given area of sandwich panel walls.

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Screws
1,600 pcs
Sealant Tubes
10 tubes
Corner Profile
80.00 m
J-Trim
60.00 m

Panel-type adjustment factor: 1.00.

How this works

We multiply the total panel area by a per-m² baseline rate, then apply a small adjustment factor for the panel core material:

screws         = ceil(area × 8    × factor)
sealantTubes   = ceil(area × 0.05 × factor)
cornerProfile  = area × 0.4  × factor   (m)
jTrim          = area × 0.3  × factor   (m)

Adjustment factor by panel type:

Rockwool:                 1.10  (+10 %)
PUF:                      0.95  (−5 %)
EPS / Glasswool / XPS / PIR: 1.00

Screws and sealant tubes are rounded up to whole units — you cannot order half a screw. Corner profile and J-trim metres are reported as continuous lengths since suppliers cut to size.

Worked example

A house with 200 m² of total panel area, EPS core (factor 1.00):

  • Screws = ceil(200 × 8 × 1.00) = 1,600 pcs
  • Sealant tubes = ceil(200 × 0.05 × 1.00) = 10 tubes
  • Corner profile = 200 × 0.4 × 1.00 = 80.00 m
  • J-trim = 200 × 0.3 × 1.00 = 60.00 m

Switching to Rockwool (factor 1.10) raises the screw count to 1,760 and the corner profile to 88.00 m. Switching to PUF (factor 0.95) drops the screw count to 1,520 and the corner profile to 76.00 m.

Sources

  • Industry rule-of-thumb fastener density and accessory rates for sandwich panel cladding (Korean / EPS / PUF systems)

FAQ

What accessories does this calculator size?

Four line items per square metre of panel: self-drilling screws (8/m²), sealant tubes (0.05/m² — roughly one tube per 20 m² of panel), aluminium or galvanised corner profiles (0.4 m/m²), and J-trim or U-channel for panel terminations (0.3 m/m²). The output is the bill of quantities you'd hand to your panel supplier or site stores.

Why is the answer different for Rockwool versus PUF?

Different cores need different fastener densities. Rockwool is denser and needs slightly longer screws at slightly closer spacing to bite cleanly through both skins and the mineral core, so we add 10 percent across the board. PUF is lighter and more compressible — pack screws too tight and the foam crushes locally, so we subtract 5 percent. EPS, Glasswool, XPS, and PIR sit at the baseline.

How is the total panel area calculated?

Sum the m² of every wall and roof you plan to clad in panels. Use the Panel Quantity Calculator for walls (gross wall area minus openings) and the Roof Panel Calculator for sloped roofs (footprint times slope factor). Add those two figures and feed the total into this calculator. For a quick estimate, a 1,000 ft² single-storey home typically has 200–300 m² of total panel area.

What does 'sealant tubes' refer to and which type should I use?

Standard 300 ml cartridge tubes used in a caulking gun. Use a polyurethane or hybrid MS-polymer sealant rated for exterior use — silicone is too soft for panel joints and acrylic is not weatherproof enough. The 0.05 tubes/m² baseline assumes you seal panel-to-panel joints, panel-to-frame perimeter, and around openings with a 6–8 mm bead. Multi-tone interior detailing or wider exterior beads will push the figure up.

Do corner profiles include both internal and external corners?

Yes — the 0.4 m/m² figure is an average across both internal (re-entrant) corners and external (salient) corners for a typical residential layout. For a building with many bay windows, jogs, or stepped levels, increase the multiplier to 0.5–0.6 m/m². For a simple rectangular shed with only four external corners, the figure can drop to 0.25 m/m².

What is J-trim used for and where does it sit?

J-trim (or U-channel) is the L-shaped or J-shaped extruded metal section used wherever a panel terminates against another surface — at the top of a wall under the eaves, around door and window perimeters, at the floor where the panel meets the plinth, and at any vertical edge that isn't a corner. The 0.3 m/m² baseline covers the typical perimeter for a single-storey house. Multi-storey buildings with floor breaks need more.

Should I order extra to allow for site cuts and damage?

Yes. Add 5–10 percent on top of the calculator's output to cover cutting losses, wrong cuts, transit damage, and a small reserve for repairs in the first months after handover. For corner profiles and J-trim specifically, having one extra 3 m length on site is cheap insurance — running short by half a metre on the last day of installation is much more expensive.

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