Warranties and cover


Safety Alert Gas Boilers Flues in Voids

Gas Boilers - Flues in Voids

Advice for Homeowners
1 April 2013

In October 2008 (updated December 2010), The Health and Safety Executive (HSE) issued a safety alert to raise awareness of a potential risk from a particular arrangement of flues for gas boilers where the flue may pass through a void, such as a ceiling void.

It is important that gas appliances (including the flue) are regularly checked to ensure that they are in a good condition and are working correctly. There is a legal duty for gas engineers to examine and confirm the effectiveness of the flue whenever they undertake work on an appliance such as a boiler. Systems that are not annually checked and maintained are at a greater risk of failure that could lead to poisonous gasses, including carbon monoxide, escaping and placing occupants at risk. Current industry guidance for new installations recommends that where certain types of flue are installed within a concealed void then suitable access arrangements should be made to allow the flue to be examined. Between 2000 and 2007 there were a number of properties built with flues in voids without suitable access to allow visual inspection.

It is recommended that for existing installations where there isn't a suitable means of access to examine the flue then hatches should be retrospectively fitted, it is also preferable that a carbon monoxide alarm is installed. Since 1 January 2013 gas engineers are advised to place systems with concealed flues and without correct access arrangements 'At Risk' and with the homeowner's permission, turn off the appliance until inspection hatches are fitted. In exceptional circumstances where fitting hatches is not practical, void monitoring devices may be an acceptable alternative when they are installed in accordance with recognised industry guidance.

HSE and Gas Safe Register offer up to date safety advice and background information. This is available at:



If you are a builder or developer, more information is available here.

What you should do

As part of the normal maintenance of your home, gas appliances should be regularly checked by a competent engineer. Engineers should be members of the Gas Safe Register. If a check has been done within the last 12 months, the Gas Safe Register member should have brought any problems to your attention. If necessary refer back to them if you have concerns or need further advice.

If the installation has not been checked in the last 12 months, you should arrange to have a check carried out by a Gas Safe Register member. Details can be obtained from: The Gas Safe Register http://www.gassaferegister.co.uk tel 0800 408 5500.

If your property is rented and a landlord or managing agent arranges the checks, you should contact them for advice.

NHBC cover - properties up to 2 years old

In the first 2 years of your Buildmark cover, your builder is responsible to put right any defects or damage reported to them which are caused by a non-compliance with NHBC technical standards that were applicable when your property was built. In the unlikely event that inspection hatches have not been provided, their omission could be a defect and builders/developers may have responsibility under the Buildmark cover to install them.

If you have concerns or require advice on the installation, you should contact your builder in the first instance. If you do not have your builder's details, contact NHBC Customer Services on 0344 633 1000.

If you believe there may be a problem or the builder has not fully investigated, then contact NHBC Claims for advice on 0344 633 1000.

NHBC cover - properties over 2 years old

In years 3-10, NHBC provides insurance cover for any the cost of putting right any defect in a flue or chimney resulting from non-compliance with NHBC Technical Requirements which causes a present or imminent danger to physical health and safety. This part of the Buildmark insurance does not cover the cost of retrospectively installing inspection hatches or void monitoring devices if there is otherwise no evidence of any problem with the flue. However, if any defect in the flue is identified, which is a present or imminent danger to the physical health and safety of the occupants, the cost of rectifying this will be met by NHBC.

In the first instance you should arrange for a visit to be carried out by a Gas Safe Register member to check the installation. If their report indicates any problems with the flue that could result in a present or imminent danger to physical health and safety, you should contact NHBC Claims on 0344 633 1000.

If you have any immediate safety concerns about any gas installation you should stop using the appliance and contact the National Gas Emergency Service:

England, Scotland and Wales: 0800 111 999
Northern Ireland: 0800 002 001
Isle of Man: 01624 644 444

If you are a builder or developer, more information is available here.