Root-Fixed vs Bolt-Down Gates & Bollards | Aremco Barriers
Root-Fixed vs Bolt-Down Bollards and Gates – What’s the Difference?
But what do those terms actually mean?
Both describe how the product is secured to the ground, and choosing the correct option is important. The best fixing method will depend on the product, the existing surface, ground conditions and how the equipment will be used.
At Aremco Barriers, we manufacture a wide range of manual steel vehicle access-control products for sites throughout the UK. In this guide, we explain the difference between root-fixed and bolt-down installations and some of the things you should consider before ordering.
What Does Root Fixed Mean?
A root-fixed product has a section of its post that extends below ground level.
A hole is excavated, the post is positioned at the correct level and alignment, and the foundation is then formed around it, typically using concrete.
You may also hear root-fixed products described as:
- Built in
- In-ground
- Concrete in
- Root mounted
Although the terminology varies, the basic principle is the same: part of the post is installed below ground level and secured within a foundation.
What Does Bolt Down Mean?
A bolt-down product normally has a base plate welded to the bottom of the post.
Instead of the post extending into the ground, the base plate sits on the surface and is secured using suitable fixings into an appropriate foundation or concrete slab.
You may also see this referred to as:
- Surface mounted
- Base plated
- Flange mounted
A bolt-down installation can avoid the need for a deep excavation, but that does not mean the product can simply be bolted to any existing surface.
The structure underneath still needs to be suitable for the loads imposed upon it.
What Is the Main Difference?
The simplest explanation is:
Root fixed = the post extends into the ground.
Bolt down = the post sits on the surface and is secured through a base plate.
Neither option is automatically better for every installation.
The correct choice depends on the site and the product being installed.
When Is Root Fixing a Good Option?
Root fixing is commonly used for new installations where foundations are being prepared specifically for the gate, barrier or bollard.
It can be particularly suitable where the existing surface doesn't provide a known structural foundation suitable for a bolt-down installation.
Typical root-fixed products include:
- Swing gate posts
- Fixed bollards
- Height restriction barriers
- Pedestrian barriers
- Industrial barriers
- Certain removable bollard sockets
The required foundation will depend on the product, ground conditions and installation.
What Are the Advantages of Root-Fixed Posts?
One of the main advantages is that the supporting foundation can be constructed specifically for the product.
This can provide a substantial installation for larger gates and barriers where the posts are subjected to considerable loads.
It can also be useful where the existing surface is tarmac, paving or another material that wouldn't itself provide an appropriate fixing point for a substantial steel structure.
What Are the Disadvantages of Root Fixing?
Root fixing normally involves more excavation.
Depending on the installation, this can mean:
- Cutting through an existing surface
- Excavating foundation holes
- Removing spoil
- Preparing concrete
- Allowing sufficient curing time
- Making good the surrounding surface afterwards
You also need to establish what is below ground before excavation begins.
Underground services are an important consideration.
When Is a Bolt-Down Installation Suitable?
Bolt-down products can be particularly useful where there is already a suitable structural concrete foundation or slab.
Instead of excavating a deep hole for the complete root section, the base plate is positioned on the surface and secured using appropriately specified anchors.
This can make installation more convenient in the right circumstances.
However, the words "bolt down" should never be interpreted as "bolt it to whatever happens to be there."
The substrate underneath the base plate matters.
Can I Bolt a Gate or Bollard Straight Onto Tarmac?
Generally, you shouldn't assume that tarmac alone provides a suitable structural fixing for a substantial gate, bollard or barrier.
Tarmac is a surface material and doesn't necessarily provide the strength required to resist the loads placed on the product.
If a bolt-down installation is required in a tarmac area, an appropriate concrete foundation may need to be provided beneath or within the surface.
The exact requirements should be determined for the particular installation.
Can I Bolt a Product Onto Block Paving?
The same principle applies.
Individual paving blocks aren't automatically a suitable foundation for a substantial steel barrier or gate.
There may be concrete beneath them, or a suitable foundation could potentially be constructed, but this needs to be established rather than assumed.
What About Existing Concrete?
Existing concrete can make a bolt-down installation attractive, but you still need to know whether it is suitable.
Things to consider include:
- Concrete thickness
- Concrete condition
- Reinforcement
- Distance from edges
- Cracks or existing damage
- Anchor type
- Anchor depth
- Loads imposed by the product
A thin concrete surface suitable for pedestrian use isn't necessarily suitable for supporting a large swing gate.
Are Bolt-Down Gates Easier to Install?
They can be, provided a suitable foundation already exists.
If substantial new concrete foundations need to be constructed purely to accept the base plates, the difference in installation work may be less significant.
For this reason, it is worth looking at the complete site rather than selecting bolt-down simply because it sounds easier.
Which Is Better for a Swing Gate?
Swing gates create significant forces at the hanging post, particularly as the gate leaf becomes longer and heavier.
Correct post installation is therefore extremely important.
Aremco's standard galvanised swing gates are generally supplied root fixed, with bolt-down arrangements available for certain requirements on enquiry.
If a bolt-down gate is being considered, the supporting concrete needs to be suitable for the gate and its expected loads.
Poor foundations can result in movement of the post, which may eventually cause the gate leaf to drop or become difficult to operate.
Which Is Better for a Bollard?
This depends on what the bollard is being used for.
A fixed root-mounted bollard may be appropriate where a permanent vehicle restriction is required and new foundations can be constructed.
A bolt-down bollard can be useful where suitable structural concrete already exists and surface mounting is appropriate for the intended application.
Removable and telescopic bollards have different installation requirements because they incorporate components below ground.
What About Height Restriction Barriers?
Height restriction barriers are relatively large structures, and their posts need appropriate support.
The foundations need to account for the size of the structure, its weight, wind loading, operation and site conditions.
If you are installing an opening height restriction barrier, the posts also support moving barrier sections, making alignment particularly important.
Always follow the installation requirements for the particular barrier supplied.
Are Root-Fixed Products Stronger Than Bolt-Down Products?
It isn't sensible to say that one fixing method is always stronger than the other.
A properly designed bolt-down installation into a suitable structural foundation can be extremely secure.
Likewise, a correctly installed root-fixed post can provide substantial support.
Problems generally arise when the foundation or fixing method isn't appropriate for the product.
A heavy gate installed into an inadequate foundation can cause problems regardless of whether the post is root fixed or bolt down.
Check for Underground Services Before You Dig
Before excavating for any root-fixed product, the installation area should be checked for underground services.
These may include:
- Electricity cables
- Gas pipes
- Water mains
- Drainage
- Telecommunications
- Other buried services
Don't rely solely on what can be seen above ground.
This also applies to drilling for bolt-down fixings, particularly where services may be embedded within or beneath concrete.
Ground Conditions Matter
Foundation requirements can vary according to ground conditions.
Firm, stable ground may behave very differently from:
- Made-up ground
- Loose fill
- Soft ground
- Waterlogged ground
- Ground close to retaining structures
- Areas containing buried services
For unusual or difficult sites, professional advice may be required to determine an appropriate foundation.
Don't Forget Drainage
Drainage can be particularly important for products containing below-ground components, such as telescopic and removable bollards.
Water shouldn't simply be allowed to collect indefinitely around mechanisms or within sockets.
The installation should take account of the manufacturer's requirements and the local drainage conditions.
Root Fixed or Bolt Down – Quick Guide
Consider root fixed if:
You are carrying out a new installation and can construct foundations specifically for the product.
The existing surface isn't suitable for structural anchors.
A substantial gate or barrier requires dedicated foundations.
Consider bolt down if:
Suitable structural concrete already exists.
Excavation needs to be minimised.
The particular product is designed and available for surface mounting.
The existing foundation has been confirmed as suitable for the intended loads.
What Information Should I Give Aremco?
When requesting a quotation, tell us as much as you can about the proposed installation.
Useful information includes:
- Product required
- Opening width
- Existing surface
- Whether structural concrete is already present
- Preferred root-fixed or bolt-down arrangement
- Ground conditions if known
- Photographs of the site
- Any known underground restrictions
If you're unsure whether you need root-fixed or bolt-down posts, that's fine – send us the information you have and we can discuss the available options.
Need Help Choosing Between Root Fixed and Bolt Down?
Choosing the correct fixing method is just as important as choosing the gate, bollard or barrier itself.
Aremco Barriers manufactures steel gates, barriers, bollards and manual vehicle access-control products for commercial, industrial, public-sector and private sites throughout the UK.
Standard and bespoke options are available depending on the product and application.
Speak to us before ordering if you're unsure about the fixing arrangement required for your site.
Please note: Prices displayed on the Aremco Barriers website are guide prices only. Contact us for a quotation based on your specific requirements.
Frequently Asked Questions
What does root fixed mean?
Root fixed means part of the post extends below ground level and is secured within a prepared foundation, normally using concrete.
What does bolt down mean?
A bolt-down post has a base plate that sits on the surface and is secured into a suitable structural foundation using appropriate anchors.
Is root fixed the same as built in?
The terms are commonly used to describe the same general type of installation, where part of the post is installed below ground level.
Can I bolt a gate directly to tarmac?
Tarmac itself shouldn't automatically be assumed to provide a suitable structural fixing. A suitable concrete foundation may be required beneath the installation.
Is bolt down easier than root fixed?
It can be where suitable structural concrete already exists. If new foundations need to be constructed, the difference may be less significant.
Can Aremco supply bolt-down swing gates?
Aremco's standard galvanised swing gates are generally root fixed, but bolt-down arrangements can be discussed for suitable applications.
How do I know which fixing type I need?
Consider the product, existing surface, available foundations, ground conditions and how the product will be used. If you're unsure, provide Aremco with photographs and details of the proposed installation before ordering.
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