Protecting Trees During Construction: A Simple Guide to Working in the Root Zone

When planning building works near any existing trees not just protected trees, it’s important to protect their roots. BS 5837:2012 offers clear guidance to make sure trees stay healthy during construction. Here’s a straightforward breakdown of what to consider.

What Is a Root Protection Area (RPA)?

The RPA is the space around a tree that needs to stay undisturbed to keep the roots healthy.

How to work it out:

• Measure the tree trunk 1.5 m above ground (in mm)

• Multiply that by 12 and convert to metres for the radius

• Draw a circle using that radius—this is your RPA

• The maximum RPA is capped at 707 m² (a circle 15 m in radius)

Show this clearly on your drawings to keep it protected.

No-Dig Zones Explained

Inside the RPA, digging by machine is not allowed. Instead:

• Keep soil levels and structure as they are

• Use hand tools or air-powered tools only

• Only remove the top layer of turf if absolutely necessary (up to 50 mm)

Any deeper work must be agreed with a qualified arboriculturist and clearly documented.

Hard Surfaces in the RPA

You’re allowed to cover up to 20% of the RPA with paths or similar, but only if:

• You don’t dig below turf level

• You build on top using methods like raised decks or reinforced cellular systems

• You avoid compacting the soil—use ground protection mats

• You use permeable materials that allow air and water to pass through

Barriers and Ground Protection

Before construction begins, install tree protection:

• Erect fencing around the RPA (e.g. scaffold frames with mesh panels)

• Use boards or mats where temporary access is needed

• Put up signs that clearly mark it a protected zone

Keep these in place until all work is complete.

Digging Near Trees (When Absolutely Necessary)

If approved works need to happen within the RPA:

• Make sure contractors understand the root protection rules

• Dig by hand or use air tools carefully

• Keep any healthy roots intact

• Wrap exposed roots in damp fabric until you backfill

• Use sharp sand or loose stone to backfill gently

At BetterLivingSpace, we’re not arboriculturists—but we make sure our designs work with the trees, not against them. Right from the early stages, we follow the principles of BS 5837 to shape layouts that consider tree root zones, protection areas, and buildability. This proactive approach means smoother approvals, fewer surprises, and designs that work in harmony with both the landscape and planning expectations.

To discuss how we can help plan tree-friendly construction, contact BetterLivingSpace Ltd at www.betterlivinspace.co.uk or call 03301 757 601.