What is a Green Roof Root Barrier?
Well my friends, this may come as a shock to you. But green roof root barriers are largely impenetrable, waterproof pieces of (typically and preferably recycled) plastic that prevent roots from breaking through your roof’s waterproof and drainage layers. Whilst rather conveniently providing an excellent platform for your growing medium.
If you don’t have a root barrier, you’re at risk of water damage, compromised insulation and structural integrity.
And the first rule of green roof club is that you never damage a living roof’s structural integrity. You really don’t want to have to re-do your green roof.
The 6 Best Green Roof Root Barriers
TDP DuPont Strongest Root Control Barrier
DuPont’s Root Control Barrier is designed to provide efficient protection against root growth for almost any type of urban infrastructure you can think of – piping, pavements, sewage networks (really!) – it’s made of stern stuff.
As you’d have to be to spend your days keeping roots out of sewers.
It also claims to prevent rhizome propagation (bamboo again) – and with it’s rot-resistance and recyclable properties we can’t recommend it highly enough.
Especially with a 2.5kg total weight.
DuPont Bamboo Root Control Barrier
The material is abrasion resistant, weatherproof and will prevent almost any root growth from permeating through. The fact this barrier was designed to mitigate invasive bamboo growth – the world’s fastest growing plant – says it all.
TCS Geotechnics Terram ROOTGUARD PLUS
TCS Geotechnics Terram ROOTGUARD PLUS – wordy I know – is a durable, long-lasting root barrier created to prevent root damage on all manner of surfaces.
What makes it so suitable for green roofs is a) its durability b) resistance to punctures and c) weather resistance.
Todds Bamboo Root Barrier
YouGarden Bamboo Root Control System
YouGarden’s Bamboo Root Control System is a great value, lightweight root barrier designed to work against bamboo root growth.
It comes in two sizes – 4m x 0.7m and 7m x 0.7m – and is ideal for lightweight green roof structures.
Permagard Green Root Roof Barrier Membrane
Permagard’s Root Barrier Membrane is manufactured from 100% polypropylene – which makes it insanely durable.
The non-woven green roof barrier material is also designed to be tear-resistant and, thankfully, it’s suited for both flat and pitched roof projects.
Whilst this root barrier is suitable for extensive and intensive roofs, heavy duty intensive roofs will need something a little sturdier.
Root Barrier 325
The Root Barrier 325 is completely impermeable. It’d be like trying to mash a Cheesestring through a safe door.
Well not quite, but you get the idea. Those roots of yours won’t be going anywhere with this uniquely formulated coating.
It comes in an array of sizes – up to 50m rolls – and you can join two sections of it together with Rootbarrier Joining Tape.
Green Roof Root Barrier FAQs
Yes, you need a root barrier for your green roof. Unless you want the re plant roots to grow through your waterproof and drainage layers, until they crack through your shed roof and ruin the structural integrity and waterproof nature of the project.
Even if you just have a roof consisting of tiny pre-planted sedums and wildflowers we’d still recommend it.
It depends. Extensive sedum roofs usually need a root barrier of a couple of mm in depth.
Semi-intensive roofs – especially ones with shrubs and small trees – are better suited to root barriers of up to 1cm.
But for your typical DIY green roof project a couple of mm thick would be fine.