HETAS registered installer since 2013
01462 431910

Installing Woodburners in Herts, Beds & Bucks

GTD Installations Ltd

Take a look at surrounds, fireplaces and open fires that we have installed

"Love love love the new wood burner" - Les from Weston

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Changes to the building regulations were introduced in 2010. Before this a wood burning or multifuel stove could be installed using only the existing masonry chimney to remove the potentially dangerous fumes from the stove. All stoves installed after 2010 must meet very specific conditions to be considered safe. The easiest way to achieve this is by using flexible liner.


If your stove was installed before 2010 there is a good chance that it does not have a liner. There should also be a cowl to stop animals from entering your flue / chimney and creating harmful blockages.


Liners can degrade over time and will need regular sweeping to prolong their life. This is best done at the beginning of Summer.

Flexible Liner

904 / 904 Flexible

904 grade stainless steel liner is thicker than 316 and is used to connect the cowl to the enamelled pipe on the stove. As it is more robust it is suitable for wood, gas, oil, coal and also coke, peat & smokeless fuel. It has a 35 year product replacement guarantee HETAS approved product.

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316 / 316 Flexible

Flexible liner made of 316 grade stainless steel is used to line the chimney connecting the cowl on the chimney pot to the vitreous pipe exiting the woodburning or multifuel stove. Suitable for wood, gas, oil and coal, and has a 10 - 15 year life expectancy for these fuels. HETAS approved product.

Call us to arrange a free quotation survey today on 01462 431910 or email gareth@chimneysweep.info

One free quotation per address for customers within 15 miles of Hitchin, Hertfordshire.  Quotes are valid for 90 days. 

Flue Liner Installation


Building Regs. 2010

Another requirement of the regulations is the hearth area, which is the area underneath the stove and directly in front of it.


These regulations have recently been reduced and state that the hearth should extend 225mm in front of the stove.


We recommend honed granite but other suitable materials are  marble, stone, tiles and precast concrete. More about hearths



Download Building Regs Part J

Suspending Cowl

A suspending cowl (also known as a pot hanging cowl) is attached to the chimney pot and holds the liner in place.


It will protect the opening from the weather and also from birds as it is surrounded by steel mesh.


As stainless steel lasts for years longer than cheaper materials; we only supply cowls made of 316 Stainless Steel from HETAS approved suppliers.


Access Hatch

Another requirement of the 2010 regulations was to ensure that when a stove is installed that adequate access is provided to sweep the chimney in the future.

You would find an access hatch in the section of black vitreous pipe that directly connects to your stove. They are mainly used on stoves without a removable throat plate.

Throat Plate

You will find the throat plate inside the stove at the top. It is a very important part of the stove and is what makes your woodburner more efficient by slowing down the release of heat up the chimney.

It should never be removed unless by a chimney sweep when cleaning the chimney.

Call us to arrange a free quotation survey today on 01462 431910 or email gareth@chimneysweep.info

If you are within 15 miles of Hitchin. Further distances will be subject to a travelling fee.

Connecting Adaptor

Your liner should connect to the vitreous pipe with a special adaptor.

We only use connectors made from stainless steel from HETAS approved installers



You may find that by insulating the area between the flue lining and the brick chimney wall that you make the most of the heat produced by your woodburning stove. Rockwool can also be used for the same purpose.


The fire bricks inside your stove are also made of this heat resistant material. Give us a call if you need to replace your fire bricks.

"Looks FAB!!! - Shelley in Clophill

Vitreous Pipe

Your stove must have a length of vitreous enamelled pipe to connect it to the liner. It is suitable for Gas, Oil and Solid Fuel appliances.


Flexible liner must not be connected directly to the stove under building regulations and bends are discouraged.


We only use vitreous stove pipe from HETAS approved installers

gallery/vitreous stove pipe

"We are very pleased with the work, and would have no hesitation in contacting you again" - Alan in Letchworth