Metal post holders, commonly known by the brand name Metposts, have transformed the way fence posts are installed and repaired. These galvanised steel brackets eliminate the need for digging deep holes and mixing large quantities of concrete for every post. Whether you are erecting a new garden fence, securing a timber structure to a concrete base, or replacing a single rotten post, metal post holders provide a faster, cleaner, and often stronger solution. Unlike traditional methods that require post-hole diggers, tampers, and waiting for concrete to cure, Metpost-style anchors allow you to set posts in minutes and proceed with your fencing work immediately.
This guide covers the main types of metal post holders available, how to choose the right size for your project, and the step-by-step process for installing each style correctly. For more background on effective fence building techniques, our dedicated resource covers layout planning and panel fitting in detail.
Understanding Metal Post Holders and Their Applications
Metal post holders are steel brackets shaped to accept a timber fence post at one end and either a spike, a bolt-down plate, or a concrete shoe at the other. They are manufactured from heavy-gauge steel and treated with a dual-layer protective coating, typically zinc plating followed by powder coating, to resist rust and corrosion even when buried in damp ground. The most common types fall into three broad categories.
Drive-In Post Spikes
These consist of a metal socket welded onto a set of sharpened prongs or a single long spike. You drive the spike into the ground using a sledgehammer or a专用的 driving block, and then slot the timber post into the socket and tighten the side screws. Drive-in spikes are ideal for soil conditions that are relatively firm and free of large roots or rubble. They work well for garden fences, boundary markers, and lightweight gates.
Bolt-Down Post Holders
These holders have a flat steel base plate with pre-drilled holes instead of ground spikes. You fix them to an existing concrete surface, such as a patio, driveway, or concrete footing, using expanding anchor bolts or chemical fixings. Bolt-down holders are the preferred choice when the ground is too hard or too shallow for a spike, or when you need to mount a post on top of an existing slab without breaking up the concrete. The same principle of using appropriate fixings and anchors in construction applies whether you are working with timber, steel, or masonry substrates.
Concrete-In Post Holders
These are heavy-duty steel shoes designed to be set into a fresh concrete footing. The holder is positioned in the wet concrete and held level until the mix cures. Once set, the shoe provides an extremely stable base that resists lateral movement and uplift forces. Concrete-in holders are best for large fences, gate posts that carry heavy side loads, or situations where soil conditions are too loose for drive-in spikes. If you are building a simple fence in a residential garden, our dedicated project page covers the full sequence from setting out to finishing.
Choosing the Correct Size of Post Holder
Selecting the right size is critical for a secure installation. Metal post holders are sized by the cross-section of the timber post they accept, typically measured in inches. Common sizes include 3×3 inch (75×75 mm), 4×4 inch (100×100 mm), and 5×5 inch (125×125 mm). The general rule is to match the holder exactly to your post dimensions; an oversized holder with packing shims is less rigid and can allow the post to twist over time. A thorough understanding of different fencing materials and installation methods will help you choose the right anchor system for your specific substrate.
| Post Size (inches) | Metric Equivalent | Recommended Spike Length | Typical Application |
|---|---|---|---|
| 3 x 3 | 75 x 75 mm | 400 – 450 mm | Light garden fence, small gate |
| 4 x 4 | 100 x 100 mm | 450 – 600 mm | Standard boundary fence, side gate |
| 5 x 5 | 125 x 125 mm | 600 – 750 mm | Heavy-duty fence, driveway gate |
The length of the spike or embedded section is equally important. A longer spike provides more lateral resistance in soft ground. As a benchmark, the spike should be at least one-third of the total post height above ground. For a 1.8-metre fence, you would want approximately 600 mm of spike buried below ground level.
How to Install Drive-In Post Spikes
Drive-in spikes are the most straightforward type to install, but they require careful alignment and the correct tools. Follow these steps to achieve a professional result.
- Mark the position. Use string lines and pegs to establish the fence line. Mark the centre of each post position with a peg or spray paint.
- Position the spike. Place the spike on the mark with the socket facing upward. Ensure the spike aligns with the direction of your fence line so the post sits correctly.
- Use a driving block. Never hit the metal socket directly with a hammer, as this can deform the holder and prevent the post from fitting. Instead, insert a driving block into the socket or place a stout piece of timber on top of the spike and strike that.
- Drive in stages. Tap the spike a few inches at a time, checking alignment frequently with a spirit level. A slight lean at this stage will become a major problem once the post is installed.
- Check depth. Drive the spike until the base flange is flush with the ground or slightly below. The socket rim should be at least 50 mm above ground to keep the post end out of standing water.
If the ground is particularly hard or contains stones, it may be necessary to pre-dig a pilot hole using a crowbar or post-hole digger. Drop the spike into the hole, backfill firmly around it, and then drive it home. For soft or sandy soils, consider using a longer spike or switching to a concrete-in holder for better stability. If you are repairing a damaged fence post, these levelling steps are just as critical to ensure the replacement stands straight.
Installing Bolt-Down and Concrete-In Post Holders
Bolt-down holders require a solid concrete base. Start by positioning the holder exactly where you want the post, then mark through the pre-drilled holes onto the concrete below. Drill holes to the correct diameter for your anchor bolts, clean out the dust, and insert the bolts. Tighten each bolt progressively using a socket wrench, alternating between bolts to ensure even pressure. A torque setting of 10 to 15 Nm is usually sufficient for M10 bolts into sound concrete.
For maximum holding power, especially in concrete that may be weak or contain air voids, use chemical fixings. Drill the holes, inject the two-part epoxy or resin into the hole, and insert threaded bar studs. Allow the chemical to cure fully before bolting down the holder. This method creates a mechanical bond that far exceeds standard expansion anchors. This is especially important for corner posts and gate posts that must meet structural load requirements for lateral stability and code compliance.
Concrete-in holders are set during the pouring of a fresh concrete footing. Dig a hole approximately 450 mm square and 450 mm deep, place your formwork if needed, and pour the concrete. Push the post holder into the wet concrete so the base plate sits flush with the finished surface. Use a spirit level to check the holder is plumb in both directions, and brace it in position with pegs and timber offcuts. Allow the concrete to cure for at least 48 hours before inserting the post.
Getting Post Holders Level and Plumb
One of the most common mistakes with metal post holders is failing to get them perfectly level before the concrete sets or the fixings are fully tightened. Even a two-degree tilt at the base translates to a noticeable lean at the top of a 1.8-metre fence panel. Here are practical techniques to ensure accuracy.
- Use washers for adjustment. On bolt-down holders, place steel washers beneath the base plate on the low side to bring the holder level. This works well for small discrepancies of up to 5 mm.
- Mortar bed for larger corrections. If the concrete surface is significantly uneven, mix a small batch of sharp sand and cement mortar. Place a bed of mortar underneath the holder, bolt it down over washers to maintain the correct height, and allow the mortar to stiffen before final tightening.
- Check with a post level. A post level is a specialised tool that straps around the post and shows bubbles on two adjacent faces simultaneously. It is much more accurate than a standard spirit level for vertical alignment.
- Account for play. Most post holders have a small amount of lateral play in the socket before the side screws are tightened. Position the post absolutely vertical, tighten the screws gradually, and check the alignment again once the screws are fully tight.
Repairing Broken Fence Posts with Repair Spikes
Fence posts most often fail at or just below ground level, where moisture and soil contact cause the timber to rot. In many cases, the fence panels and gravel boards are still in good condition, and the concrete footing around the original post is sound. Repair spikes are designed specifically for this scenario, allowing you to replace the rotten section of post without excavating the existing concrete.
The repair process is straightforward:
- Cut off the damaged post. Use a handsaw or reciprocating saw to cut the broken post off flush with the ground. Remove the rotten timber and clear any debris.
- Position the repair spike. Slide the repair spike down between the remaining timber stub and the surrounding concrete. The spike channels are designed to fit into the narrow gap left when a post rots within its concrete collar.
- Drive the spike home. Protect the top of the spike with a scrap of timber and drive it into the earth using a sledgehammer or mallet. The base of the repair spike will come to rest on top of the old concrete, providing vertical support.
- Insert the new post. Slot the replacement post into the repair spike, check for plumb, and tighten the side screws. The new post is now supported by the original concrete footing and the ground beyond it.
For posts where the concrete collar is too wide to accommodate a standard repair spike, a larger L-shaped repair bracket is available. This bracket drives into the ground next to the concrete and wraps around the post, secured with rust-proof screws through pre-drilled holes. Both methods eliminate the need for digging out old concrete, saving hours of labour and keeping the surrounding garden undisturbed.
Metal post holders and Metposts offer a modern alternative to traditional concreting methods for fence posts. Whether you choose drive-in spikes for speed, bolt-down holders for concrete surfaces, or concrete-in shoes for heavy-duty applications, the key to a long-lasting installation lies in careful alignment, correct sizing, and proper fixing techniques.