Fabricators and installers are still unclear about the latest updates to Approved Part L and Approved Part F of the Future Homes Standards and their implementation, according to Rehau.

The company says that conversations with installers and fabricators have highlighted 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.

Steve Tonkiss, head of sales south at Rehau Windows, said: “In both 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 they 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 installers and fabricators. 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.”

According to Rehau, it has also received questions about windows with profiles too narrow for trickle vents.

Specifically, installers wanted to know if window profiles with vents placed in the sash and the head of the outer frame could be used. In a similar vein, they also asked if it was possible to use a disclaimer if a homeowner refused to have trickle vents.

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, alternative placements can be used if weather performance is unaffected.

“If doing so does influence the window’s 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 installers to issue disclaimers to omit the use of trickle vents.”

Rehau’s commercial technical team has developed four fact sheets to assist installers and fabricators.

For more information, click here.