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Building support buying guide

Updated: 23 October 2026

You have a concrete pad, a timber post or a joist, and a search page that calls every fitting a building support. A post base, a decking pedestal and a telescopic rod do different work. This building support buying guide puts the job first, then the gap in millimetres, then the plate or the head, then the coating and the screws. The [building support comparison](/hub/diy-supplies/building-support) lists the amazon.co.uk packs, with shelf prices captured on 19 and 20 October 2026. Peter F. read those listings. This is not a lab test. A qualifying purchase through the links can earn a commission at no extra cost to you.

You have a concrete pad, a timber post or a joist, and a search page that calls every fitting a building support. A post base, a decking pedestal and a telescopic rod do different work.

Our top picks

Ceta Composite Decking Ceta Composite Decking pedestal, pack of 10

Best overall

Ceta Composite Decking Ceta Composite Decking pedestal, pack of 10
8.9/10about £33.99
View offer
FWEEK FWEEK 4-piece elevated post base, 100–150 mm

Alternative

FWEEK FWEEK 4-piece elevated post base, 100–150 mm
8.9/10about £23.99
View offer
Generic 5-piece decking pedestal, 30–60 mm

Best value

Generic 5-piece decking pedestal, 30–60 mm
7.6/10about £10.98
View offer
On this page
  1. 1.Three supports, three jobs
  2. 2.Height and bearing
  3. 3.Coating and fixings
  4. 4.When the listing is not enough
  5. 5.Which family to open first

Three supports, three jobs

An elevated post base is a steel stand-off under the end of a post, so the end grain sits above wet concrete. In this set that is a threaded jack from 100–150 mm, a taller pair from 15–23 cm, or a bolt-down U at 80 × 80 × 250 mm. A decking pedestal is a polypropylene foot under a joist, titled 30–60 mm or 60–140 mm. A telescopic rod is a temporary third hand, in bands of 30–59 cm, 50–115 cm, or a title of 120–290 cm. It is not an acrow prop. If you are unsure whether the timber ends on the fitting or lies across it, use the post base or decking pedestal fork.

Height and bearing

Measure the clear gap in millimetres and keep the units apart. One five-pack title says 30–60 mm and a bullet prints 60–140 cm. The Ceta title says 60–140 mm while other lines also print 18–30 mm, 30–60 mm and 60–135 mm. Buy the band the title states. FWEEK, AHAQU and QWORK print an upper plate of 75 × 75 mm, so a 100 mm post overhangs it. Simpson’s 64.8 kN applies only with the fasteners named for the APB100/150. It does not transfer to these listings, and none of them print a design load.
Ceta Composite Decking Ceta Composite Decking pedestal, pack of 10

Testsieger

Ceta Composite Decking Ceta Composite Decking pedestal, pack of 10
8.9/10about £33.99
View offer

Coating and fixings

Galvanised on these amazon.co.uk bullets is a seller word. EN ISO 1461 is batch hot-dip after fabrication, so cut edges receive zinc. EN 10346 is sheet coated before cutting, so later edges are bare. None of these packs cite either standard, and a black colour is not a known thickness of zinc. Screws in the box are often absent or are not concrete anchors. The how to fit a building support page is the order of work once those anchors are in your hand.

When the listing is not enough

A light garden frame on an existing pad is the work these stars describe. A balcony, a carport, a hot tub, or a deck tied to the house needs a design. The Ceta seller line of 1662 kg/m², and the 40 kg or 70 kg figures on the rods, are not an independent test. HSE’s temporary-works guidance says even a proprietary screw prop needs a load assessment. Trade elevated bases warn against a fence post whose head is free. Aleawol’s listing is 5.0 from one review, and the file has no review text. That star is not evidence of a finished shed.

Which family to open first

If the end grain sits on the fitting, start with a steel base whose plate covers the post and whose title covers the gap. If the timber lies across the head, start with a pedestal in the millimetre band you measured. If you only need a second pair of hands, use a rod inside its title length and take it down once the bracket holds. Stop for a balcony, a free fence post, or a prop under a wall.

Common questions

Which height band matches a 40 mm gap, a 120 mm gap and a ceiling?
A 40 mm gap under a joist matches pedestal titles of 30–60 mm. A 120 mm gap under a post matches steel jacks of 100–150 mm. A ceiling points to rod titles of 50–115 cm or a claimed 120–290 cm, rather than a 30–59 cm cabinet rod. Extra height lines on the same page are clashes. They are not a promise that one pack contains every band.
Will a 75 × 75 mm plate cover a 100 mm post?
The upper plate on FWEEK, AHAQU and QWORK is 75 × 75 mm, so a 100 mm post overhangs it. Aleawol’s upper plate is 8.3 × 10 cm and LLB is 80 × 80 mm. A trade APB or PPRC top is cited at about 100 × 100 mm. Simpson’s kilonewton figure stays with that trade product and its named fixings.
Does galvanised on these listings mean EN ISO 1461?
The files do not show that citation. Listings say galvanised, electroplated, polished or anti-rust. FWEEK’s bullets say galvanised steel and an electroplated finish. A review of QWORK says the steel is painted. Treat the word as a claim until you can see the coating, and do not read a black finish as a known outdoor life.
Are the screws in the box concrete anchors?
Often they are not. FWEEK reviewers bought anchors because the supplied screws did not suit concrete. Ceta reviewers report no screws or bolts. AHAQU names 16 screws in a bullet and prints 1 in the components field. LLB’s components line is No. Wood screws will not hold a post base to concrete.
Is a 40 kg or 70 kg rod an acrow prop?
Eummy and Dandelionsky print a 40 kg seller line. INCENDIOS prints 70 kg and 69.85 kg. Those figures are not falsework ratings, and these listings do not show loads that fall as the pole extends. Reviews use the rods for a cabinet, a tile batten or plasterboard. One UK review says an INCENDIOS clamp slipped and needed a G-clamp. Take the rod away once the real fixing holds.

Related pages

Best building support

Building support

Decking pedestals for a shed base: height and rules

How to fit a building support without the wrong screws

Post base or decking pedestal: post end or a joist

Sources

Public UK sources and the amazon.co.uk listings compared on this page. Shelf prices read 19 and 20 October 2026. Updated 22.10.2026.

  1. Planning Portal decking permission (retrieved 22.10.2026)
  2. GOV.UK householder technical guidance (retrieved 22.10.2026)
  3. Approved Document K (retrieved 22.10.2026)
  4. Dorset Council decking note (retrieved 22.10.2026)
  5. Approved Document A (retrieved 22.10.2026)
  6. HSE temporary works (retrieved 22.10.2026)
  7. EGGA galvanizing specification guidance (retrieved 22.10.2026)
  8. Simpson Strong-Tie elevated post base PPA (retrieved 22.10.2026)