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REHAU Answers Lingering Questions about Future Homes Standards Updates

Five months after the introduction of the Future Homes Standards Regulation updates, a prominent polymer supplier has been engaging with architects and found that questions about the modified rules remain.


Following significant changes to building regulations, updates have been made to Approved Part L and Approved Part F of the Future Homes Standards, covering energy efficiency and ventilation in new and existing properties respectively. According to REHAU, the considerable time gap between the updates and their implementation risks the spread of outdated information, which could raise risks of potentially non-compliant projects in the sector.

The polymer provider’s conversations with architects highlighted potential confusion surrounding the circumstances in which trickle vents are required. Specifically, questions arose concerning kitchens with hood vents over the hob and ovens, and when mechanical ventilation is used upstairs alongside chimneys on lower floors.

Addressing the two different conditions, Steve Tonkiss, Head of Sales at REHAU South, said: “In both of these cases trickle ventilation is still required. Chimneys aren’t a method of controlled ventilation; however, air bricks could possibly be fitted instead as long as meet the required Building Regulation requirements and evidence can be provided to show this.

“No matter the method chosen, ventilation of any gas or combustion appliance must be done in line with Approved Document J’s guidance on the safe installation and usage of heating appliances. In the same way, kitchen hoods don’t replace the use of trickle vents either as they aren’t continuous methods of ventilation as they are intermittent extraction.”

Conformity to ventilation guidelines was also found to provoke uncertainty among architectural stakeholders. For example, questions arose around whether acoustic trickle vents need to meet the same Equivalent area (EQA) standard as regular trickle vents, and whether glazing vents can be used as an alternative method of aeration.

Considering Part F and Part L of FHS, Steve said: “All sound attenuation ventilators must comply with the minimum equivalent area (EQA) of background ventilators for natural ventilation guidelines as outlined in table 1.7 of Part F regulations. They must also be marked according to the relevant type of ventilation system detailed in section 1.16. In light of this, when it comes to using glazing vents as an alternative, provided they perform to the requirements of table 1.7, they are a viable solution.”

Situations can arise in which building standards are obstructed, for instance, REHAU personnel had often received questions about windows with profiles too narrow for two minimum sized trickle vents. Specifically, architectural specifiers wanted to know if the vent could be placed in the sash and the head of the outer frame. In a similar vein, other stakeholders asked if a homeowner refused to have trickle vents can a disclaimer be signed to cover the installer with building compliance bodies FENSA or Certass.

Steve said: “In circumstances where the window does not present enough space for side-by-side trickle vents, as close to the minimum as feasibly possible or alternative placements can be used if weather performance is unaffected. If doing so does influence the windows performance, the homeowner or installer could approach building control to seek their advice and approval. In the situation of non-compliance by a homeowner there is unfortunately no facility for customers or installers to issue disclaimers to omit the use of trickle vents.”

With this uncertainty in mind, REHAU’s commercial technical team have developed four fact sheets to assist designers and specifiers across commercial building projects.

For more information on and support understanding the Future Standard, click here.

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