correct position of roof vents.

[mattu27]

Morning all,

Looking to fit a tile vent in a Marley ashmore roof for bathroom extraction.

We've just had the roof redone using cromar vent 3 pro membrane and ashmore tiles with a dry ridge/hip system and intended on putting the extraction vent in the soffits but are unsure if this would be ok as we have had eaves tray vents fitted.

If we were to vent via a tile where should it be positioned? I've seen so many roofs with them fitted in every possible location.

I.e 3 rows below the ridge, 3 or 5 rows up from the eaves, middle of roof.

Would we be ok to extract at the soffits, or would the eaves vents pull the moist air back into the roof space?

Thanks.

 

[^woody^]

Wherever you like, whatever it's easiest.

Soffit extraction is ok as long as you can get the duct down there without it squashing, or the tight bend reducing the fan extract rate.

 

[garyo]

I've wondered if you have the option to put a vent anywhere, then should you aim to get the vent roughly level with the extract point to prevent losing too heat from the house in a chimney effect when the extract is switched off?

 

[^woody^]

I've wondered if you have the option to put a vent anywhere, then should you aim to get the vent roughly level with the extract point to prevent losing too heat from the house in a chimney effect when the extract is switched off?

There will be (or should be) a back-draught shutter in the fan or duct

 

[garyo]

There will be (or should be) a back-draught shutter in the fan or duct

I hear what you're saying, but the two bathrooms in my last house had neither with their cheapo screwfix inline extractors and soffit grills. Don't ask me how I know.

 

[mattu27]

Wherever you like, whatever it's easiest.

Soffit extraction is ok as long as you can get the duct down there without it squashing, or the tight bend reducing the fan extract rate.

Once again the most straightforward help I could've asked for. Could I pick your brain further?

So am I ok to duct straight out of the soffit even though I have eaves vents fitted?

I'm hopefully going to duct two bathrooms together out of the same soffit point. Using two backdraught stops in the lines and decent fans is this doable?

Thanks, Matt

 

[mattu27]

Could anyone help with a bit more info regarding my last post?

 

[^woody^]

Normally, joining two fans to a single duct or outlet can cause efficiency, excessive noise, and back draught issues - even where shutters are fitted

 

[mattu27]

Thanks woody,

I don't fancy having two soffit vents on the back of the house but that seems like it's the only option of ducting into one isn't the best route.

I've purchased two tile vents with duct adaptors but didn't fancy making holes in the recently tiled roof to put them in. And I'll have to insulate the ducting aswell I'm assuming?

Thanks

 

[^woody^]

You could try your single vent idea and see if it works out. Would you have anything to lose in trialling it?

IMO, soffit vents are last resort and tile vents would be better - there always seems to be black dirt or staining around them and grime and fluff in the grill - and this stands out on white soffit.

You don't need to insulate the duct, unless it's rigid pipe and only then it's really to reduce sound reverberation. But any duct should angle down towards a soffit vent, and if vertical may need a moisture trap. You may want to throw some loft insulation over the first bit that comes up from the ceiling.

 

[mattu27]

Thanks again woody,

The soffits and fascias were replaced along with the roof membrane etc and so are currently without and holes.

I completely agree (and so does the missus apparently) that soffit vents look ugly when installed and will be a dust trap.

I'm thinking that I install the two tile vents inline but maybe ten or so tiles apart so that the duct run isn't unnecessarily long.

Assuming I can fit these pretty low down on the roof as they're purely to vent the condensation from the bathrooms? Say 4th row up?

Thanks.