A wet fireplace

[davidscones]

I have uncovered an old fireplace in my house - a 1850s stone cottage in Cornwall. The fireplace was hidden behind sheets of plastic and poorly laid modern facing stone with cement. The original stonework is understandably a bit more damp than I would like it to be from being held behind sheets of plastic for decades most likely. This is a party wall so i’m guessing the damp has come from the ground. Some of the stone is very soft to the touch, almost like cheese. It would be great to hear someone’s thoughts on how much of a problem this is... will the stone harden up when it dries out or is it rotten and needs to be repaired? I plan to install a log burner so hopefully that will help with the moisture. Photos attached! Thank you

 

[Edward Ian]

Hi,
Has the chimney been capped off? If not, that would be why the chimney is damp, rain water coming down the flue and nowhere to go.
If you are going to install a wood burner, you will need to line the flue with one of these https://www.stovesonline.co.uk/wood_burning_stoves/Flexible-Flue-Liners.html
You would need to dry it out first though, I would have thought.

 

[davidscones]

Hello Edward. chimney has been capped for decades!

 

[MatthewC]

Hello Edward. chimney has been capped for decades!

But what about the condition of flashing and pointing? One small crack in a bit of lead caused massive dampness down the joint chimney breast of my house and the neighbouring one for years - until I had the roof done and the issue was found and fixed.

Having removed the plastic you could just leave it alone for a few months and see if it dries at all (although checking as above is still a good idea).

 

[davidscones]

Hello Matthew. Thanks for your thoughts I will make sure the chimney is checked when the burner is being installed.

 

[Gothichome]

David, with the cap on the chimney is it pulling a draft? If not, you could open up the cap and install a rain cap on it. A draft will help with the drying out process. The down side, do to the season, you will drawing heat out of the home.

 

[davidscones]

Hello Gothichome
Thank you. Good idea. My real concern however is not so much the damp but how much damage might have been done to the stone.

 

[a twig]

Just light a big ole fire in it, dry everything out double plus quick :twisted: :twisted:

 

[Abi Cott]

Without knowing the geology of the stone it's very hard to tell.
It looks like a possible shist. Which would make sense with Cornish geology. Is it hard layers with soggy bits inbetween?

 

[malcolm]

My real concern however is not so much the damp but how much damage might have been done to the stone.

I have a fireplace which when uncovered revealed soft red bricks that had been soaking wet for years and had become a lot more soft than intended. After a couple of years the fireplace is dry but the bricks are still very soft. I wouldn't hold out a lot of hope that the stone will recover as it dries out. The edge of my opening had been knocked around so I've plastered to the outside of the fireplace opening and will leave the bricks inside exposed around the woodburner.