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Have a look at this https://www.heritage-house.org/damp...-have-i-got/salt-damage-in-old-buildings.html
Our house which was a back-to-bare-brick project was built by wife's great grandad in 1902 - we know it's whole life history. For over 100 years it had a coal fire every day in the middle room fireplace. The walls in that room, and particularly around the fire place are very prone to hygroscopic salts and "damp" (half way up an internal wall coinciding with dabs is NOT "rising damp"!). I have proved the damp comes from the room air, because isolating the wall surface with damp-seal paint stops the surface salts growing.
I have also discovered that walls lined with PB fixed with dot and dab can cause spots where the dabs are - the water in the dabs draws salts from the walls as it evaporates to dry. These salts continue to attract moisture.
I have also discovered that walls boarded using adhesive foam and/or with insulated plasterboard are absolutely fine the foam doesn't "wet" the wall causing salts to migrate. I certainly wouldn't render the outside - if any damp does get in the wall fabric through either penetration or condensation, the bare brick outside will allow it to evaporate. Seal the outside surface and you risk sealing it in.
I have read loads of articles and reports, and by and large I agree with everything on the heritage-house site because it seems to correlate with the actual experience I have had in an old house.
Obviously sort out leaking drainage, uncapped and unused chimneys, but I would focus on the problem of warm, fairly humid, room air either being drawn to hygroscopic salts, particularly around chimneys and/or condensation on cold spots - particularly around the bottom of solid walls. Once you start thinking about the "damp" coming from the room air, it moves you towards different solutions.
Round a fire place I would seal the wall with SBR slurry and overboard with PB using foam adhesive. Inside a fireplace, if I wanted to board it as a feature I would fix to top-hat metal section isolating the board from the salt-loaded bricks. Wet trades to salt-loaded bricks just seems to cause a problem.
It may have a ventilated cavity - I'm struggling to see a header course as you would on a solid wall, and there do appear to be some airbricks for cavity ventilation? maybe? If so I would think about internal insulation, because should there be any interstitial condensation (witha colder wall behind insulation) the ventilation in the cavity should evaporate it. Worst case would be internal insulation, solid wall and rendered external as any interstitial condensation would have nowhere to go.
All my opinion - others will definitely vary !!
Our house which was a back-to-bare-brick project was built by wife's great grandad in 1902 - we know it's whole life history. For over 100 years it had a coal fire every day in the middle room fireplace. The walls in that room, and particularly around the fire place are very prone to hygroscopic salts and "damp" (half way up an internal wall coinciding with dabs is NOT "rising damp"!). I have proved the damp comes from the room air, because isolating the wall surface with damp-seal paint stops the surface salts growing.
I have also discovered that walls lined with PB fixed with dot and dab can cause spots where the dabs are - the water in the dabs draws salts from the walls as it evaporates to dry. These salts continue to attract moisture.
I have also discovered that walls boarded using adhesive foam and/or with insulated plasterboard are absolutely fine the foam doesn't "wet" the wall causing salts to migrate. I certainly wouldn't render the outside - if any damp does get in the wall fabric through either penetration or condensation, the bare brick outside will allow it to evaporate. Seal the outside surface and you risk sealing it in.
I have read loads of articles and reports, and by and large I agree with everything on the heritage-house site because it seems to correlate with the actual experience I have had in an old house.
Obviously sort out leaking drainage, uncapped and unused chimneys, but I would focus on the problem of warm, fairly humid, room air either being drawn to hygroscopic salts, particularly around chimneys and/or condensation on cold spots - particularly around the bottom of solid walls. Once you start thinking about the "damp" coming from the room air, it moves you towards different solutions.
Round a fire place I would seal the wall with SBR slurry and overboard with PB using foam adhesive. Inside a fireplace, if I wanted to board it as a feature I would fix to top-hat metal section isolating the board from the salt-loaded bricks. Wet trades to salt-loaded bricks just seems to cause a problem.
It may have a ventilated cavity - I'm struggling to see a header course as you would on a solid wall, and there do appear to be some airbricks for cavity ventilation? maybe? If so I would think about internal insulation, because should there be any interstitial condensation (witha colder wall behind insulation) the ventilation in the cavity should evaporate it. Worst case would be internal insulation, solid wall and rendered external as any interstitial condensation would have nowhere to go.
All my opinion - others will definitely vary !!
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