Eve's/Soffit ventilation Question

[rhubarb1092]

Hi. I've just had the above replaced with UPVC.

The installer has provided over-facia vents (10mm); 1m vent every 5m, which he states is sufficient. Is this right?

The roof span is 4.8m x 8.8m long (pitch is greater than 15 degrees).

I've read BS5250 (and other advice) and it states that the ventilation should be 'continuous' (presumably the whole length of the facia?).

Advice greatly appreciated.

BTW - he hasn't been paid yet!

 

[Mw Roofline]

Hi. I've just had the above replaced with UPVC.

The installer has provided over-facia vents (10mm); 1m vent every 5m, which he states is sufficient. Is this right?

The roof span is 4.8m x 8.8m long (pitch is greater than 15 degrees).

I've read BS5250 (and other advice) and it states that the ventilation should be 'continuous' (presumably the whole length of the facia?).

Advice greatly appreciated.

BTW - he hasn't been paid yet!

I don't understand, one every 5 metres? So what is using up the space in between them? This can't be right...or am I not understanding correctly, LOL

 

[noseall]

Overfascia vents occupy the top of the entire length of fascia. There is no such thing as intermittent spacing - as you say it should be continuous.

 

[Mw Roofline]

I've read BS5250 (and other advice) and it states that the ventilation should be 'continuous' (presumably the whole length of the facia?).

Yes it should. The OFV sits on top of the fascia all the way along. It lifts the tiles by 15-20mm.

If you stick OFV's here and there then the tiles will drop in between and look all wavy

 

[rhubarb1092]

Thanks for your responses; confirms what I thought. a 1m x 25mm (I think) 'notch' has been cut in the top of the facia to accommodate the vent(s), so adjacent tiles are on the same level.

 

[Mw Roofline]

Thanks for your responses; confirms what I thought. a 1m x 25mm (I think) 'notch' has been cut in the top of the facia to accommodate the vent(s), so adjacent tiles are on the same level.

Well he must have ran out of vents as its a bit of a ball ache to cut notches out of the fascia.

Personally, I don't think one vent every 5 metres is enough. If you don't mind, why don't you have a few circular ventilators drilled into the soffit board? This would help by causing a 'flow' of air IE in the circular and out of the OFV.

I'm sure he has done a good job, just never heard of this periodic notching thing, lol