I have a 17thC farmhouse that we have been renovating since 2004. We had the roof re-slated in 2007 with all new flashings etc and had the chimney stacks re-built in 2010 - 3 of them.
We re-used the bricks when re-building the chimney stacks and used NHL3.5 for the mortar and NHL5 for the flaunching. There was no lead tray and I didn't add one when the stacks were re-built.
The house has no loft space so all of the bedrooms have a vaulted ceiling to the underside of the roof.
At first the damp on the walls under the ridge covered the same area - a triangle reaching about 1-2ft below the ridge and I thought that would dry out over time, maybe getting a little worse before it got better. However, in our room which has the middle stack in it, the damp has recently (within the last 8 weeks) crept nearly all of the way down the wall, blowing the lime plaster in places.
I called the roofer and joined him up on the roof to discuss what might be the problem. At first I thought that wind driven rain was somehow getting under the flashings or under the tiles but all seemed very tight and sound around the base of the stack. It therefore does not appear that the quantity of rain that would cause that amount of damp in a short space of time was coming through the roof slate/flashing.
The flaunching was intact with no cracks but the west facing part of the chimney stack was cold and covered in moss.
The only thing the roofer could suggest is that the rain is saturating the bricks on that side as it evidenced by the moss and causing the stack to be very cold and either resulting in condensation inside or actually seeping down the wall into the bedroom.
Any thoughts?
We re-used the bricks when re-building the chimney stacks and used NHL3.5 for the mortar and NHL5 for the flaunching. There was no lead tray and I didn't add one when the stacks were re-built.
The house has no loft space so all of the bedrooms have a vaulted ceiling to the underside of the roof.
At first the damp on the walls under the ridge covered the same area - a triangle reaching about 1-2ft below the ridge and I thought that would dry out over time, maybe getting a little worse before it got better. However, in our room which has the middle stack in it, the damp has recently (within the last 8 weeks) crept nearly all of the way down the wall, blowing the lime plaster in places.
I called the roofer and joined him up on the roof to discuss what might be the problem. At first I thought that wind driven rain was somehow getting under the flashings or under the tiles but all seemed very tight and sound around the base of the stack. It therefore does not appear that the quantity of rain that would cause that amount of damp in a short space of time was coming through the roof slate/flashing.
The flaunching was intact with no cracks but the west facing part of the chimney stack was cold and covered in moss.
The only thing the roofer could suggest is that the rain is saturating the bricks on that side as it evidenced by the moss and causing the stack to be very cold and either resulting in condensation inside or actually seeping down the wall into the bedroom.
Any thoughts?