Specialist Chimney Lining
Specialist Chimney Lining in London, Hertfordshire & Essex
Not every chimney can be lined with a steel liner. Open fires, older chimneys with bends and offsets, listed properties, thatched properties, and flues with unusual dimensions all present challenges that standard methods can't solve. That's where FuranFlex25 RWV comes in.
SweepSmart is an accredited Kompozit'allUK installer for FuranFlex25 RWV composite chimney lining across London, Hertfordshire and Essex. Our engineers are factory trained and certified annually to ensure every installation meets the required standard. This isn't something we've bolted on as an extra service. It's a specialist capability that allows us to line chimneys other companies can't.
What Is FuranFlex25 RWV?
FuranFlex25 RWV is a composite flue liner made from thermosetting resin reinforced with fibreglass. It's inserted into the chimney as a flexible hose, inflated at very low pressure (reducing stress on the existing structure), and then steam-cured until the resin sets to a rigid, steel-strength lining.
Once cured, it forms a seamless, gas-tight, acid-resistant liner that moulds precisely to the shape and size of your existing flue. There are no joints, no gaps, and no reduction in the flue's cross-sectional area.
Why Choose FuranFlex25 RWV?
It solves problems that steel liners can't. It can be installed in chimneys with bends, offsets, and irregular dimensions that would prevent a rigid liner from passing through. It's less than 4.5mm thick, so it maximises the internal diameter of the flue rather than reducing it. It's suitable for solid fuel appliances and open fires, with heat resistance tested to 1,000 degrees Celsius. It's gas-tight and watertight with no joints along its entire length. It can be installed in one day, with the appliance ready to use immediately after curing. It comes with a comprehensive 25-year guarantee. And it's the only composite flue lining tested and approved to the relevant British Standards and listed by HETAS.
It's been used successfully on listed properties and thatched properties across the UK, where preserving the original chimney structure is essential.
How Is FuranFlex Installed?
The liner is inserted into the flue as a flat, flexible hose. It's then inflated with air at very low pressure, conforming to the exact shape of the chimney. Steam is applied to trigger a chemical reaction in the resin. Once the resin reaches curing temperature, it sets rigid. The entire process typically takes a single day, and the chimney can be used as soon as the liner has cured.
Because the installation pressure is minimal, there's very little stress on the existing chimney structure. This makes it particularly suitable for older, more fragile chimneys where a forced liner could cause damage.
When Would You Need Specialist Lining?
Your chimney has bends or offsets that prevent a standard steel liner from being installed. You have an open fire and need a larger diameter lining. The property is listed or thatched and the chimney must be preserved. You're reinstating an old chimney that hasn't been used in years. A standard lining method has been ruled out due to the flue's construction.
If you're not sure whether your chimney needs standard or specialist lining, we'll assess it during a camera inspection and recommend the right approach. We'll always use the simplest, most cost-effective method that's safe and appropriate for your setup.
Got a chimney that can't be lined by standard methods? Get in touch and we'll assess it. We're an accredited FuranFlex installer, Guild of Master Sweeps member, and Which? Trusted Trader with over 1,000 five-star reviews.
How Does FuranFlex Compare to Steel Lining?
Steel liners are the standard method for stoves and closed appliances. They're effective, well-proven, and we use Schiedel products for all our steel lining work.
FuranFlex is the solution when steel can't do the job. Larger flues, chimneys with bends, period properties where the structure can't be altered. It's not a replacement for steel lining. It's the answer when steel lining isn't an option.
The right method depends on your appliance, your chimney's construction, and what the camera inspection reveals. We'll always recommend the approach that gives you the best result for your situation.
Read more about our standard chimney flue lining here.