So with all the rain we had in June, we developed a bit of a damp issue in our new study at the exposed brickwork around the top edge of our now disused chimney breast.
I suppose it always existed, but we never noticed it before because the water never penetrated far enough to reach below the suspended ceiling. Even when we had opened up the ceiling up to the rafters, we still didn’t notice an issue because it wasn’t evident until we painted the brick white. (Perhaps not the most forgiving of colour choices in the end).
After a roof inspection by my builder to ensure that all the flashing and tiles were in good order, numerous coats of white paint, and a coat of stain block, we determined that the cause of the damp was likely the open chimney pots.
You aren’t supposed to cement off dis-used chimneys as damp can get trapped inside the brickwork and you still need to allow for ventilation – so what is the solution?
After speaking with numerous chimney specialists, it turned out that a C-Cap would be most suitable for our dis-used chimneys (a bargain at just £19.99 each). Not only does the C-Cap allow for ventilation while preventing water ingress, it also stops birds and insects nesting, and helps prevent heat loss in the winter (as recommended by the Energy Saving Trust).
However, as nothing is ever simple, we needed toto confirm which 2 of the 4 chimney pots were ours, and which were our neighbours as we share the same chimney and water from their chimney pots could also result in damp on our shared wall. This was achieved two weekends ago with smoke pellets that were lit on my neighbour’s side. You can just faintly see the smoke in the second chimney pot in the image on the right. If you are doing this I’d recommend doing this on a sunny day rather than a grey smoke coloured day to make things easier to see as it is pretty subtle! This test revealed that the two matching ventilated terracotta pots towards the street were our neighbours.
As our neighbours intend to install wood burners in the future – we needed to find a different cowl for their pots. Unfortunately however the only suitable cap a metal, elevated cap cannot be fixed to their ventilated chimney pots. (Check first before buying as different sources of fuel require a different cowl)… This would mean a costly replacement of their chimney pots, and the purchase of the C-Cap covers. Understandably not something they were willing to embark on at this stage.
The end result was that our neighbours kindly agreed that we could install C-Caps over their chimney pots for the time being. When our neighbour decides to install their wood burner, we will address the terra-cotta pots and water cowls again then.
Now we just need to wait a week or two for the brick to dry out, and then try painting again…