Heavy Duty 4mm Galvanised Elevated Bolt-Down Post Base Bracket

Hot-dip galvanised steel post base bracket, made from 4mm plate, that bolts straight down onto a concrete footing to hold a square timber post elevated above ground level – lifting the vulnerable end grain of the post clear of standing moisture rather than leaving it sitting flush against damp concrete.

Timber rot at ground level is driven almost entirely by end grain: the cut end of a post soaks up and holds water far more readily than its sides, so a post set directly onto or into damp concrete tends to rot from the base first, often long before any damage becomes visible further up the post. Whether that moisture comes from the surrounding soil around a buried post, or simply from the porous surface of a concrete footing sitting wet after rain, sustained contact between end grain and moisture is what starts the process. This bracket is built to remove that risk entirely, by holding the post end permanently clear of the footing rather than resting against it.

At 4mm plate thickness it is a genuinely heavier gauge than our standard concealed post brackets – this is our heaviest-duty elevated post base, built for substantial post loads. A round steel riser tube, welded between the two square mounting plates, holds the upper plate clear of the base plate; the post sits on top of this upper plate and is fixed down through four pre-drilled screw holes, rather than being dropped into or wrapped by a socket. Standard finish is hot-dip galvanised for full corrosion protection, suiting permanent outdoor use; the 80 x 80 x 100mm (3.15 x 3.15 x 3.94in) size is also available in a black powder-coated finish as an alternative, for use where appearance matters as much as protection. For lighter posts where a lower-profile, concealed fixing is preferred over a visible elevated bracket, see our separate concealed post and concealed shoe bracket ranges.

Key Features

• Hot-dip galvanised 4mm (0.16in) steel plate – a heavier gauge than our standard concealed post brackets, built for substantial post loads
• Elevated round-tube riser lifts the post base clear of the concrete footing, keeping the moisture-prone end grain out of standing water
• Round steel riser tube welded between two square mounting plates, giving a rigid, compact connection without relying on the base plate alone
• Bolts straight down to a concrete footing, so there is no need to cast the bracket into wet concrete
• Available in three sizes, from 80 x 80 x 100mm (3.15 x 3.15 x 3.94in) up to 100 x 100 x 200mm (3.94 x 3.94 x 7.87in)
• 80 x 80 x 100mm size also available in a black powder-coated finish as an alternative to the standard galvanised finish
• Our heaviest-duty elevated post base bracket, suited to fencing, pergola, gazebo and decking frame posts
• Post is fixed down through four pre-drilled screw holes in the upper plate, giving a secure, positively located connection rather than a loose surface fixing

Specification

Material: Steel, 4mm (0.16in) plate. Finish: Hot-dip galvanised as standard; black powder-coat also available on the 80 x 80 x 100mm (3.15 x 3.15 x 3.94in) size, as an alternative to the standard hot-dip galvanised finish.

Typical Applications

Because it is built for substantial loads and bolts down to a fixed concrete footing rather than being buried, this bracket suits structural and semi-structural post work above ground-level fixings, including:

• Fence post bases, bolting down to a concrete pad to keep the post elevated instead of setting it directly into the ground
• Pergola and gazebo corner posts, where a visible, heavy-duty elevated connection suits an already-exposed structural post
• Decking frame posts and sub-frame uprights, particularly where the post sits on a concrete pad, pad stone or other hardstanding rather than being sunk into the ground
• Replacement or retrofit post bases, resetting a post that has rotted at ground level onto a bolt-down base rather than re-burying it
• Any square timber post application where substantial load-bearing capacity is needed alongside long-term protection against ground moisture
• The 80 x 80 x 100mm black powder-coated option, for visible posts on patios, garden structures or entranceways where a black finish is preferred to bright galvanised steel

Installation Guidance

Fitting is straightforward, but the sequence matters for a secure, long-lasting result:

1. Make sure the concrete footing has fully cured before fitting the bracket – bolting down to green, uncured concrete will not give a secure, long-term fixing.
2. Bolt the base plate down to the footing using anchors rated for the load and fixing type; the plate sits on top of the concrete surface rather than being embedded into it.
3. Position the timber post on the upper plate, checking it is square and vertical, then fix it down through the four pre-drilled screw holes with suitable wood screws (not included).
4. Once the post is screwed down to the upper plate, the elevated riser keeps the post end held clear of the concrete surface, so no additional packing or spacer is needed to keep the end grain out of standing water.

Order before 2pm Mon–Fri for same-day dispatch from our UK warehouse.