Eaves ventilation

[warmington_ash]

Hi,

 

We’re well into our extension project and I fear we’ve encountered a problem. Hoping for some advice on a suitable remedy.

 

The roofer has progressed the roof but has NOT installed a proprietary eaves ventilator.

 

He is a friend of mine so I am

hoping there may be an easier solution opposed to having an awkward conversation with him about stripping off the roof tiles to put one in.

 

Would this work… at the top of the external wall we have two strips of timber (see pics). Would drilling a series of holes into these timber pieces allow air get into the underside of the roof for ventilation? 

 

Any help would be appreciated.

[warmington_ash]

[warmington_ash]

[Temp]

You can get round black soffit vents like these.. 

 

https://www.roofingsuperstore.co.uk/browse/ventilation/circular-vents.html

 

However you might be surprised how many you need. Each one typically has a free opening of 2500mm^2. I think they normally recommend a slot 25mm wide which is 25,000mm^2/m.  So you need around 10 vents per meter.  

 

Don't just drill holes as you will eventually hit a rafter. Plan a pattern of vents that fits between rafters, make a jig for a hole saw etc so the end result looks uniform.

 

One potential problem... are the two strips nailed together or just to the rafters?

 

Would it be easier to take the strips down and replace with one and a linear vent?

https://www.upvcbuildingplastics.co.uk/soffit-vent-strip-black-ash-5mt-723-p.asp

 

Edited August 7, 2022 by Temp

[warmington_ash]

11 minutes ago, Temp said:

You can get round black soffit vents like these.. 

 

https://www.roofingsuperstore.co.uk/browse/ventilation/circular-vents.html

 

However you might be surprised how many you need. Each one typically has a free opening of 2500mm^2. I think they normally recommend a slot 25mm wide which is 25,000mm^2/m.  So you need around 10 vents per meter.  

 

Don't just drill holes as you will eventually hit a rafter. Plan a pattern of vents that fits between rafters, make a jig for a hole saw etc so the end result looks uniform.

 

One potential problem... are the two strips nailed together or just to the rafters?

 

Would it be easier to take the strips down and replace with one and a linear vent?

https://www.upvcbuildingplastics.co.uk/soffit-vent-strip-black-ash-5mt-723-p.asp

 

Thanks for the reply. 
 

I can drill the holes from the inside to ensure that I do not hit rafters. Therefore might the drilled holes idea work?  Pic attached.

[warmington_ash]

It is with adding that the membrane used by the roofer is Master 112 (breathable membrane). After reading some more online, I am hopeful that because this is breathable it may negate the need for any additional ventilation.

 

There will be a AVCL fixed to the underside of the roof insulation.

[Temp]

The vents normally go in the soffit not the fascia so would be hard to drill from the inside. I think the holes would also be  big enough that the strips would be cut into sections that come out unless they are glued together.

 

11 hours ago, warmington_ash said:

It is with adding that the membrane used by the roofer is Master 112 (breathable membrane). After reading some more online, I am hopeful that because this is breathable it may negate the need for any additional ventilation.

 

There will be a AVCL fixed to the underside of the roof insulation.

 

Think you will have to ask your BCO if that's OK.  Our BCO allowed it but we have tiles rather than slates .

Edited August 8, 2022 by Temp