Fence Post Support U-Shape Bolt Down Base Bracket 4mm Galvanised

Heavy duty 4mm galvanised U-shape fence post support base bracket, made for bolting timber fence posts down onto concrete, decking or other flat, solid surfaces instead of setting the post into the ground. The bracket combines a U-shaped post cradle with a bolt-down base plate, giving a strong, adjustable-free fixing that keeps the post square while you work and lets you anchor it permanently to whatever surface you're building on. It's a straightforward alternative to setting a post directly in the ground: mark out, bolt the base down, and the post is supported without digging a hole or waiting on concrete to cure.

The U-shaped cradle grips the post on three sides, reducing wobble and holding it steady and square while you fix it in place - there's no need for temporary props or stakes while the fixing goes in. The bolt-down base lets you anchor directly to a solid surface rather than digging and concreting a post hole, which is particularly useful on decking, patios, hardstanding, or anywhere a dug-and-concreted post simply isn't practical, and equally useful where you specifically want a removable or replaceable post fixing rather than a permanent in-ground one.

Just as importantly, raising the post onto a base bracket keeps the timber end lifted clear of the concrete or ground surface below, giving it room to expand and contract with the weather and reducing the risk of moisture being trapped against the end grain - a common cause of premature post rot when timber is set directly against damp concrete or buried ground contact. The Silver finish is hot-dip galvanised for maximum corrosion resistance in permanent outdoor use, while the Gold finish uses a yellow/electro-galvanised process, a different, thinner coating with a warmer tone, more commonly chosen for appearance. Both finishes can generally be over-painted with a zinc-compatible paint if you want to match a colour scheme. All five sizes are CE marked under a European Technical Assessment.

Key Features

• Heavy duty 4mm galvanised steel construction, built for long-term outdoor exposure
• U-shaped cradle grips the post on three sides, keeping it square and steady while you fix it
• Bolt-down base anchors directly to concrete, decking, paving or other flat surfaces - no need to dig and concrete a post hole
• Raises the post clear of the ground/substrate, reducing moisture trapped against the end grain and the risk of rot
• Available in five sizes covering post widths from 71mm to 121mm (2.8″ to 4.8″)
• Choice of two distinct finishes: Silver (hot-dip galvanised, all five sizes) or Gold (yellow/electro-galvanised, 80mm-120mm range only), different coating processes, not just different colours of the same finish
• Galvanised finish can be over-painted with a zinc-compatible paint if a different colour is wanted
• Well suited to removable or replaceable post fixings, not just permanent in-ground installations

Specification

• Material: Heavy duty steel, galvanised finish
• Thickness: 4mm
• Design: U-shape post cradle, bolt-down base, raises post off the ground/substrate
• Finish options: Silver (hot-dip galvanised) or Gold (yellow/electro-galvanised), two distinct coating processes
• Certification: CE marked under a European Technical Assessment (all five sizes)

Sizes (post width)

The range covers post widths from 70mm up to 120mm. The 70mm size is available in Silver galvanised only, while the 80mm, 90mm, 100mm and 120mm sizes are offered in both Silver and Gold galvanised finishes, as set out below:

Typical Applications

• Fixing new timber fence posts to a concrete base, screed or slab without digging, setting and concreting an in-ground post hole
• Garden and agricultural fencing where posts need to sit on hardstanding, yards, or existing solid ground
• Decking and patio post supports, keeping the post foot lifted clear of deck boards or paving
• Replacing an existing timber post where the original in-ground fixing has rotted, by cutting back the post and refitting it onto a bolt-down base
• Situations calling for a removable or replaceable post fixing, such as temporary fencing or screening panels
• Any project where keeping the post's end grain raised clear of damp ground or concrete, rather than embedded in it, matters for the post's working life
• Gate posts and other freestanding timber posts that need a solid, bolt-down base rather than an in-ground fixing

Installation Guidance

Because the bracket is bolted down rather than buried, fitting is a two-stage process - base first, then post:

• Choose the bracket size that most closely matches the actual width of your timber post - a snug fit in the U-shaped cradle gives the best grip and keeps wobble to a minimum
• Position and bolt down the base plate on your fixing surface (concrete, decking, paving, etc.) using fixings suitable for that substrate before fitting the post
• Stand the post in the U-shaped cradle so it sits raised clear of the ground or substrate below, keeping the end grain away from standing water
• Check the post is plumb (vertical) before final fixing, then secure it through the sides of the cradle
• Over-paint the galvanised finish with a zinc-compatible paint afterwards if you want to match a colour scheme

This base-then-post sequence also means a post can later be unbolted and replaced without disturbing neighbouring posts or the rest of the fence line - useful anywhere a removable or replaceable fixing was the point of choosing a bolt-down base in the first place.

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