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The target finished walking-surface height above the roof deck.
This is the elevation of the top of the finished pavers above the surface the pedestals actually stand on — the finished waterproofing or protection layer — as set by the project's design. Measure from there, not from the structural deck below the insulation and membrane: that build-up is not a term in this calculation, so including it makes every pedestal come out too tall by its thickness.
The thickness of the paver unit itself.
Use the actual thickness of the paver product being installed, from the manufacturer's spec sheet.
The additional height reduction needed at this specific pedestal to compensate for the sloped roof deck below.
A sloped roof deck means each pedestal's required compensation differs across the roof — this value is the compensation allowance for the one pedestal location you are calculating.
Required pedestal height
0.342 ft
Slope compensation varies at each pedestal location across a sloped roof deck — this calculates one location at a time; a full layout needs a pedestal height schedule across the roof's slope, typically provided by the pedestal system manufacturer's layout service.
They open the calculator with your figures already in it
Rooftop Terrace Paver Pedestal Height Calculator: 0.3425 ft — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
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How this was calculated
Formula source(s)
- Pedestal height = Desired Finish Height − Paver Thickness − Roof Slope Compensation Allowance — the standard sizing method for adjustable paver pedestal systems used on rooftop terraces and plaza decks, which raise pavers to a level finish surface above a sloped waterproofed roof deck.
Inputs used
- Desired Finish Height Above Roof Deck
- 6 in
- Paver Thickness
- 1.5 in
- Roof Slope Compensation Allowance (at This Pedestal's Location)
- 0.39 in
Confidence note: Slope compensation varies at each pedestal location across a sloped roof deck — this calculates one location at a time; a full layout needs a pedestal height schedule across the roof's slope, typically provided by the pedestal system manufacturer's layout service.
What this calculation does not cover
- Gives a height, not a load path. Each pedestal carries about a quarter of the four pavers meeting on its head plus the live load on them - a terrace or plaza is commonly designed at 4.8 kPa (100 psf) - and the pedestal, the paver and everything below the membrane has to take it. The insulation is the part usually forgotten: a pedestal is a point load onto a board specified for compressive strength, and the wrong board grade dishes under it and takes the finished level with it.
- Tall pedestals are not simply longer ones. Past a modest height, which varies by system but often falls somewhere between 300 and 600 mm (24 in), manufacturers require the field to be tied together with bracing, spacer rails or a clip system, because a forest of slender columns has nothing resisting sideways force otherwise - and their published allowable load per pedestal drops as the height rises. This sum returns a dimension; whether that dimension is legal at that load comes from the manufacturer's table.
- Answers with a continuous number, and pedestals adjust in steps. Products come in fixed height ranges with a threaded adjustment and a slope corrector that typically tops out around 5%, so the computed height has to land inside a range you can actually buy, and a deck steeper than the corrector's limit needs a different product or shimming. The figure is also only true if the deck is where you think it is - a 10 mm (0.39 in) hollow in the membrane under one pedestal is 10 mm (0.39 in) of rock in the paver above it, which is why the field gets levelled off the pavers as it is laid.
- Nothing here about wind. Pedestal pavers are a loose-laid ballast system held down by their own weight, and uplift at a roof's corners and perimeter zones runs several times the pressure in the middle of the field - which is why edge zones commonly need heavier or thicker units, interlocking clips, or a restraint at the parapet. A paver can be exactly the right thickness for this height calculation and still leave the roof in a gale.
Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.
Sources checked 2026-09-06 · in the site-wide review of 2026-09-06 · v1.0.1
Regulatory standards & verification citations1
- Pedestal height = Desired Finish Height − Paver Thickness − Roof Slope Compensation Allowance — the standard sizing method for adjustable paver pedestal systems used on rooftop terraces and plaza decks, which raise pavers to a level finish surface above a sloped waterproofed roof deck.
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Tools and safety for this job
To lay paving. Generic types, no brands, no prices.
Protection this work requires
- Cutting or grinding concrete, masonry, screed, tile or fibre-cement board releases respirable silica: cut wet or extract at the tool, and wear a P2/N95 respirator at minimum — a nuisance dust mask does not filter it.
- Saws, grinders and breakers run above 85 dB, where hearing damage accumulates and does not recover: defenders or plugs for every cut, not just the long ones.
- Breakers and grinders cause permanent nerve damage: limit continuous trigger time, keep hands warm, and stop if fingers tingle or blanch.
- Boards, blocks and bagged material cause most lasting back injuries on small sites: two people or a lifter for full sheets, and never a bag on one shoulder up a ladder.
Show the 8 tools this job needsHide tools
Essential
Plate compactor
Rubber mallet
Shovel and spade
Spirit level
String line and pins
Wheelbarrow
Recommended
Block splitter
Optional
Angle grinder
Also needed as materials: cutting and diamond discs.
what each landscaping tool is for, and the spec that decides which to buy where one does.