Should I install additional ventilation when installing Q-Bot's underfloor insulation?

2 December 2021

Why Q-Bot is asking questions about ventilation? (Fires / Stoves)

Building regulations are regularly updated and change over time. Primarily these changes are for Health & Safety purposes, especially with anything relating to fire safety. It is possible that the regulations relating to fire safety and ventilation for the heating appliance you have installed have changed since its installation. In order for Q-Bot to insulate your home, we are required to ensure that the ventilation that is present meets the current building regulations. As such we need to collect some additional information.


What happens if the appliance and ventilation don’t meet current standards?

If your current ventilation levels don’t meet the required standard then Q-Bot recommend you resolve this urgently. Inadequate ventilation around a fire, or fireplace can lead to the build up of noxious and harmful fumes like carbon monoxide – Do you have a carbon monoxide alarm fitted? – You may also want to consider this as you have a fire.

Link here


What is the solution / How do I ensure I have adequate ventilation?

The good news is there is plenty of guidance on the subject that can help. If there is not already a vent fitted then a vent to the outside will be needed.

Ventilation rates are now based on the air permeability of the house and the size of the appliance. Houses built after 2008 should have an Air Permeability Test result which you should have seen at the time of purchase or contact your landlord. Houses built after 2008 are far more airtight than older houses with double glazing, airtight doors and floors. If a house has an air permeability of less than 5m3/mthen the regulations state that additional ventilation will be needed to provide 550mm2 per kW of the appliance regardless of the stoves total output. For 99% of homes, those built before 2008 stoves with a greater than 5kW rating will require an externally fitted vent in the same room as the appliance. The size of the vent would needs to be a minimum of 550mm2 per kW over and above 5kW. For example a very large stove with a rating of 9kW would need a vent of (4 x 550m2 = 2200mm2) that is (sq root of 2200) a vent with the dimension of 46.9mm by 46.9mm or roughly 4.7 cms square.     

As a guideline for open fireplaces a permanent air vent should be provided giving a free area of ventilation of at least 50% of the throat opening of the fireplace.  

Vents should never be closed off or blocked and if an anti-pest guard is fitted the mesh size should never be less than 5mm.


I don’t want additional ventilation in my home, I want to insulate it because it is too draughty.

We completely understand. What you currently have is an uninsulated suspended timber floor which means you have uncontrolled ventilation drawing up cold moist air from your floor void below. Installing Q-Bot’s UFI will dramatically reduce the flow of air into your home and this can have unintended side effect. If ventilation is reduced by too much then carbon dioxide levels could build up to dangerous levels, or moisture from cooking in kitchens and using bathrooms can build up to cause damp, moisture and mould problems. Fitting appropriate ventilation will ensure a healthy environment is maintained in your home and put you in control of the ventilation.

The level of ventilation that is required is significantly lower than the draughts caused by your uninsulated floor.


How is ventilation fitted?

There are a number of solutions depending on the requirements of your home. All homes require at least intermittent mandatory ventilation (IMVsd) in bathrooms and kitchens, this requires a small mechanical (usually electrical) vent to the outside. When humidity levels are too high the fan will extract moist air which will be replaced (through depressurisation) with less humid air. This typically enters a room through, or under a door, or through a wall, or window vent. Internal doors require a 10mm undercut, and windows a closable vent which in most cases (UPVC and Wooden) can be fitted in the frame.


What happens if I don’t want the ventilation fitted?

No contractor, including Q-Bot can add insulation to a property without ensuring adequate ventilation is provided to protect you, and your property. Therefore, we cannot recommend you proceed with insulating your home without the provision of ventilation.

It is worth considering the broader impact of not fitting adequate ventilation in homes.

  • Poor air quality – Inadequate ventilation can lead to health issues such as asthma, COPD and lung cancer. More information here

  •  Condensation, damp and mould – Breathing, cooking washing and other everyday activities release moisture into the air in our homes. Where there is inadequate ventilation, this moisture will condense on surfaces (an obvious sign is steamy windows when cooking). Once water vapour has condensed it must go somewhere, typically it will collect in window frames, or be absorbed into surfaces like walls. If surfaces retain moisture for too long at low temperature, for instance at the bottom of walls then this can damage the surfaces and create mould patches, the spores of which can be harmful.

  •  The value of your property - When someone sells a property a building survey is required by the mortgage provider. This will identify whether there is inadequate levels of ventilation in a property and the lack of it can impact the value of the property (as the works will be needed to be carried out by the new owners), or the ability of potential buyers to get a mortgage.


Is there a cost to fitting ventilation?

Yes, Q-Bot are able to provide you with a ventilation strategy which identifies any additional ventilation your property requires to meet building standards. Q-Bot is able to quote for the installation of these additional ventilation measures, however you may choose to use another installer for the work, or fit measures yourself.

Where a home has non-compliant combustion ventilation, or simply a lack of combustion ventilation Q-Bot is unable to install our underfloor insulation measure until remedial action has been taken as it presents a significant health & safety risk. Remedial action to ensure your health and safety in your home may include decommissioning unused Gas Heating appliances and open fireplaces, or fitting adequate combustion ventilation adjacent to an appliance. Some appliances may not need additional combustion ventilation because they are ‘room sealed’ if this is the case for your appliance then simply providing the evidence (photo’s of ratings plate if denoted, or make and model numbers so this can be confirmed) will mean no additional provisions are necessary.


For more information, please contact us here.