Ventilation requirements when building an extension

[oldkettle]

Hi,

 

I am looking at further details for our planned bungalow to a house conversion. We will be adding first floor with a couple of bathrooms and bedrooms there. What I want to know is whether there is a requirement to have more than just a trickle/purge ventilation. The reason I am asking is I am contemplating whether to install standard MVHR unit or one of Fresh-R units with a view to install another one downstairs later as well. According to this https://www.planningportal.co.uk/info/200130/common_projects/17/extensions/7 I do not have to have mechanical extraction since there will be openable windows in bathrooms. Have I missed something? Any recommendations please?

[ProDave]

The only person that can give a definitive answer is your building control that will be signing it off.

 

A related one perhaps was I did the wiring for two terraced cottages that were being knocked through to make one larger cottage. There was a great deal of discussion about whether they would have to meed the current insulation requirements for the whole building (which would have been very hard to achieve) and in the end the answer from building control was only areas where alterations were done needed to meet the current insulation regs.  Readiong between the lines that would mean the new upstairs would need to meed current regs, but not the existing downstairs?
 

[oldkettle]

48 minutes ago, ProDave said:

The only person that can give a definitive answer is your building control that will be signing it off.

 

A related one perhaps was I did the wiring for two terraced cottages that were being knocked through to make one larger cottage. There was a great deal of discussion about whether they would have to meed the current insulation requirements for the whole building (which would have been very hard to achieve) and in the end the answer from building control was only areas where alterations were done needed to meet the current insulation regs.  Readiong between the lines that would mean the new upstairs would need to meed current regs, but not the existing downstairs?
 

From the conversation with BCO I gathered that I don't have to upgrade say walls downstairs which to me means they are only interested in extension meeting the requirements.

[bassanclan]

The amount of ventilation required depends on the square feet of the extension. You need to look in Building Regs part F.

If you don't have trickle vents in the existing windows you might get away with not having to have trickle vents.

 

On my refurb and extension, all the windows were replaced and the windows in the new 110sqm extensions had no trickle vents because the old windows didn't have them and I think they are a ridiculous idea! I didn't ask my BCO before ordering the windows and thought I might have to fit an MHVR unit, but I fessed up and my BCO said he was not concerned about the lack of trickle vents.

[oldkettle]

On 27/10/2016 at 21:48, bassanclan said:

If you don't have trickle vents in the existing windows you might get away with not having to have trickle vents.

 

Thank you.

When I say trickle ventilation I mean the night vent position on windows. But it seems it is mentioned in BR: usage is "not recommended because of the difficulty in measuring the equivalent area(!) etc." It probably does not mean "not allowed" though.

And I agree standard trickle vents are not a good idea, found it impossible to keep them clean.

 

It seems will have to talk to BCO about it as recommended.