Why does my main roof not have venting?

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JamesAsus

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But a small overhang over the downstairs loo and hallway does?


So my main roof of the house has 2 vents BUT they are connected to the bathroom and ensuite extractor fans.

However a small roof overhang at the front of the house, covers about 3 metres wide by 2 metres deep has 2 vents.

I've noticed all the other houses in the estate are the same. Is there any logical reason why this would have been done?

I ask because I have no venting in a small area of roof above a recently converted garage which is completely sealed (no hatch or anything), it's 6 metres squared, according to building regs I should have it vented BUT my main loft is not vented, is substantially bigger and I don't appear to have any major rot or mold or moisture issues?

The felt isn't breathable I don't think, it's the hard plastic type. In winter we dry clothes indoors as well but never noticed any major issues in the main loft. It's not a particularly well insulated hatch either.

House is 30 years old with rockwoll insulation.
 
JamesAsus said:
But a small overhang over the downstairs loo and hallway does?


So my main roof of the house has 2 vents BUT they are connected to the bathroom and ensuite extractor fans.

However a small roof overhang at the front of the house, covers about 3 metres wide by 2 metres deep has 2 vents.

I've noticed all the other houses in the estate are the same. Is there any logical reason why this would have been done?

I ask because I have no venting in a small area of roof above a recently converted garage which is completely sealed (no hatch or anything), it's 6 metres squared, according to building regs I should have it vented BUT my main loft is not vented, is substantially bigger and I don't appear to have any major rot or mold or moisture issues?

The felt isn't breathable I don't think, it's the hard plastic type. In winter we dry clothes indoors as well but never noticed any major issues in the main loft. It's not a particularly well insulated hatch either.

House is 30 years old with rockwoll insulation.
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Does it have breathable membrane?
 
No eaves vents then? These aren't always obvious eg sometimes directly beneath the tiles above the fascia.
 
freddiemercurystwin said:
No eaves vents then? These aren't always obvious eg sometimes directly beneath the tiles above the fascia.
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I genuinely can't see any form of ventilation at all, definitely none in the soffit board and I'm pretty sure there's none above the fascia that I can see either.

Plus why have fascia vents on the top roof but tiled vents on the bottom section (over hallway and downstairs loo).
 
I can show you several thousand properties within a 20 minute radius of me with no roof ventilation. If we walk further we'll find thousands more.

And the roof timbers are still up and working as they were 60 years ago.

So the answer to your question is "because that's how it was built".
 
^woody^ said:
I can show you several thousand properties within a 20 minute radius of me with no roof ventilation. If we walk further we'll find thousands more.

And the roof timbers are still up and working as they were 60 years ago.

So the answer to your question is "because that's how it was built".
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My main question is why on earth the builder would ventilate a small lean to roof on the ground floor of the property which only overhangs a downstairs loo (with no shower) and hallway but not the huge roof space at the top of the property, makes no sense logically. The bigger the area the more moisture will travel into the space and cause condensation issues?

Also I've seen a lot of older properties than mine with roof tile vents, like 60 year old properties.
 
Because the size and design of a roof void can dictate the ventilation requirements. As can changing regulations.
 
^woody^ said:
Because the size and design of a roof void can dictate the ventilation requirements. As can changing regulations.
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In my case a very small section of roof space has 2 roof tiles vents.

However a very large section of roof space has none.

It also looks to be roughly the same roof angulation for them both.

Seems like the complete opposite of what should be required, all houses in my estate are the same, not sure on the logic behind it given NHBC say small (3m squared or less) roof voids don't need ventilation.
 
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