Condensation in loft after reroofing and chimney stack removal

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Thanks in advance to all who contribute.

We recently had the roof replaced on our 1920s mid terraced house, which is on a hill; it was the original slate roof with no membrane and a chimney stack (not shared with next door).

We had it replaced with a tile roof, felt / membrane in the loft and also requested the chimney stack to be removed, as the chimney breast is closed up and we previously had issues with water ingress through the flashing of the stack etc.

The roofer put 4 tile vents and supposedly ridge vents in (it doesn’t look like there’s any fascia / soffit vents), however on the side of the loft where the chimney stack used to be, we’re having condensation on the membrane and rafters. He came back to address it initially by making slices in the membrane by the ridge, although in the space of a month, this made no difference. He’s come back again in the last few days and put further slices in the membrane by where the stack used to be. He’s confident with these measures and time being allowed for moisture in the chimney breast to leave, the condensation will stop.

He previously offered to come back and fit a further 2 vents by where the stack used to be, however he later said this wouldn’t be possible (something to do with the size of the roof tiles close to the rafters on that side not being big enough to be replaced by a standard size vent tile? - I could be inaccurate about what he said, perhaps someone knows a reason why they can’t be?)

The chimney breast was removed to a level just below that of the new roof.

I’m just wondering if anybody knows whether or not the condensation is likely to dissipate? Or what alternative solutions there are for tackling the issue? The roofer is adamant no form of vent can be installed in the area where the stack used to be. Also, is making slices in membrane for ventilation something commonly done in the trade?

Many thanks again
 
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Is the stack ventilating a warm and humid room, into the loft?

It's usual to have gaps round the eaves, not blocked with insulation, allowing air to blow through. In my house you can see glimmers of daylight. Your roof might be different.
 
Warm air is raising through the chimney stack into the cold loft and condensate.
Why didn't they remove all of the chimney stack to ground floor?
 
The stack isn’t being used for anything; it’s completely blocked up.

The only daylight I can see in my loft is from the 4 vent tiles they’ve fitted.
Is the stack ventilating a warm and humid room, into the loft?

It's usual to have gaps round the eaves, not blocked with insulation, allowing air to blow through. In my house you can see glimmers of daylight. Your roof might be different.
 
Warm air is raising through the chimney stack into the cold loft and condensate.
Why didn't they remove all of the chimney stack to ground floor?
We live in a mid terraced house, so I assume removing it to the ground floor would have been difficult/ impossible?
 
I don't know how your roof is made. Can you show some photos of the eaves, inside and out, with the insulation pulled back?
 
Have you read this?

 

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