Fence Post Spikes: Sizes, Driving Tools & Support Types
Fence post spikes are metal supports with a pointed ground section and a holder for a timber fence post. They are driven into suitable ground and can provide an alternative to a new concrete footing where the support, ground conditions and fence design allow.
Choose fence post spikes for a suitable new-ground installation, bolt-down post supports for a suitable existing base, or repair spikes for replacing posts already set in concrete. These fittings do different jobs. Start with the installation type, then measure your timber and check the support dimensions, finish and pack contents.
This guide explains the main choices in our fence post fittings range, including 75mm and 100mm post supports and driving tools. The right choice depends on the ground, fence design and condition of any existing foundation.
Which fence post support do I need?
| Support type | Typical starting point | What to check |
|---|---|---|
| Drive-in fence post spike | A timber post in suitable ground | Actual post width, support length, ground conditions and compatible driving tool |
| Fence post repair spike | A damaged timber post with an existing concrete surround | Post size, soundness of the old concrete and the specified repair method |
| Bolt-down post shoe | A post on a suitable existing solid base | Base condition, plate dimensions, fixing positions and specified anchors |
| Concrete-in post shoe | A support set into a new concrete foundation | Post size, foundation detail and concrete curing requirements |
A standard ground spike is not a substitute for a repair spike, and a concrete-in shoe is not a bolt-down plate. Compare the product drawing with the job before ordering.
75mm or 100mm fence post spikes: measure first
A 75mm fence post spike is described for nominal 75 × 75mm square timber; a 100mm version is described for nominal 100 × 100mm timber. These are commonly called 3-inch and 4-inch posts, but nominal inch labels are not an exact fitting check. Measure the finished post where it enters the holder, including any treatment or swelling, and compare it with the product specification.
Post width and support length are separate dimensions. Compare our 75 × 75mm fence post spikes with the 100 × 100mm fence post spikes using the current product drawing. Check whether a stated length describes the overall support, its holder or the ground spike section; never use one of those measurements as a substitute for another.
The distinction matters with repair supports too. Our 75mm repair spike has a 300mm spike section and a separate 150mm holder, giving a 450mm overall length.
Bolt Secure or Quick Fit fence post spikes?
These names describe how the holder grips the timber post. Choose the retention method as well as the post size and finish.
- Bolt Secure: clamping bolts tighten the holder around the post. The bolts can be undone when the timber needs replacing.
- Quick Fit: inverted fins inside the holder grip the post without side-clamping bolts. Check the timber size carefully and follow the fitting instructions for that support.
Our TIMCO galvanised Quick Fit spike range includes nominal 75mm and 100mm options. Retention style does not by itself establish a load rating or the right support for a particular fence.
Drive-in spikes, bolt-down shoes or concrete?
Drive-in post spikes can avoid a new concrete footing where the ground and fence design suit that method. Hard obstructions, buried rubble, roots, loose fill or unsuitable ground can prevent correct installation. Stop if the spike meets resistance or will not remain aligned; extra hammering does not establish that the location is suitable.
For an existing base, compare the 100mm red oxide bolt-down shoe with the galvanised bolt-down post shoe range. The surface must support the fixing loads: a paving slab or thin surface layer is not automatically an adequate foundation. Hole size alone does not determine the correct anchor.
If the support is to be cast into a new footing, choose a concrete-in fence post shoe and follow the specified foundation detail. No support's size or marketing name provides a universal fence-height, gate or wind-load rating.
Fence post spike finishes: grey, red/brown or galvanised silver?
Choose the finish as well as the post size. Grey fence post spikes, red or brown-looking supports and galvanised silver spikes can look similar in search results, but the colour is not a specification for the coating, strength or service life.
| Finish | What to check | Shop the range |
|---|---|---|
| Grey spikes | Grey describes the visible finish. Check the stated coating rather than assuming every grey support is galvanised. | 75mm grey spikes · 100mm grey spikes |
| Red / brown spikes | Our red oxide supports have a reddish-brown appearance; the shade can vary. Choose the specified red oxide finish, rather than relying on the photograph's colour alone. | 75mm red oxide spikes · 100mm red oxide spikes |
| Galvanised silver spikes | Choose the galvanised option when that coating is required. The metallic finish can vary in appearance; assess the actual coating specification and exposure conditions. | 75mm galvanised spikes · 100mm galvanised spikes |
Check the timber treatment, moisture and exposure when selecting the coating, and inspect it after installation. No finish makes timber immune to decay or gives every support the same fence-height or load capacity. Tool inclusion and pack quantities are separate from the finish: check the selected listing.
Do I need a fence post spike driving tool?
A compatible driving tool sits in the post holder so you can drive the spike without striking and distorting the holder's top edges. Match the tool to the support; do not assume one size fits every spike.
Selected Fixings Direct spike packs include a driving tool. Check the product's pack contents before adding another. The selected pack determines the number of supports; an included reusable tool does not mean one tool per spike. Separate 75mm driving tools and 100mm driving tools are also available for compatible supports.
Do fence post spikes work?
Yes, where the support specification, ground conditions and fence design suit a driven-in support. They are not suitable for every location or fence. A longer spike alone does not establish that it can support a particular fence height, exposed location or gate. Check the installation requirements before choosing between a ground spike and a different foundation or support.
How to install a drive-in fence post spike
Tools and parts to have ready
- Tape measure and a fence line: mark out the actual panel and post positions.
- Spirit level or post level: check the post holder in both vertical directions.
- Compatible driving tool and the specified hammer: protect the holder while driving the spike.
- Matching posts, supports and fixings: check the selected pack contents, including any clamping bolts or reusable driving tool.
- Plan the positions. Check the boundary, actual panel dimensions and intended fence layout. Identify underground services before penetrating the ground; see HSE guidance on underground services.
- Check the kit. Confirm the post size, support, driving tool and specified fixings. Wear appropriate protection for hammering work and keep others clear.
- Set the alignment. Position the spike and insert its compatible driving tool. Check both vertical directions and the holder's orientation against the fence line.
- Drive and recheck. Use the manufacturer's installation method, checking alignment frequently. Stop if an obstruction, damaged component or unsuitable ground prevents correct placement.
- Fit the post. Remove the tool, seat the timber as instructed and secure the specified clamp or fixings. Inspect the completed support before fitting panels or applying loads.
Use the instructions for your exact support for installation depth, fixings and permitted application. There is no single embedment or post-spacing rule that fits every range.
When should I use a fence post repair spike?
A repair spike is a distinct option for an old timber post already surrounded by concrete. The specified spike fits between the remaining timber and concrete to provide a holder for the replacement post. Check that the remaining foundation can be retained; damaged concrete or a different failure may require another repair.
For diagnosing loose panels, failed rails or post damage, use our separate fence repair guide. For choosing between ground supports, return to the comparison above.
Before you order
Confirm the support type, measured post width, drawing dimensions, outdoor finish and pack quantity. Red oxide and galvanised finishes are different specifications; neither is a guarantee against all corrosion or timber decay. Read the exact product download and check whether clamping bolts, foundation anchors and a driving tool are supplied. Then choose the appropriate option in fence post spikes, shoes and driving tools.
Technical sources and further help
The Bolt Secure and Quick Fit comparison is based on TIMCO’s fence post support range guide. It covers several sizes and finishes; use the row for the exact product you are buying. For a support-specific drawing or fitting query, contact Fixings Direct with the product, measured post size and intended installation.
