Cavity walls (2000+ years old!) allow air circulation within the wall, and damp-proof courses cut off capillary action from the soil.<\/p>
https:\/\/npshistory.com\/publications\/preservation\/masonry-walls-moisture.pdf<\/a><\/p> But the problem of moisture balance is way, WAY more complex than that. There's vapor pressure and thermal effects for each layer of the wall, and those forces change throughout the year with internal and external heating and moisture.<\/p> https:\/\/www.wbdg.org\/resources\/moisture-management-concepts<\/a> is hands-down the best overview I've come across for this problem.<\/p>","url":"https:\/\/woof.group\/@aphyr\/115979513397039730","status_net":{"notice_id":null}},"to":[{"objectType":"http:\/\/activitystrea.ms\/schema\/1.0\/collection","id":"http:\/\/activityschema.org\/collection\/public"}],"status_net":{"conversation":"tag:gnusocial.jp,2026-01-29:objectType=thread:nonce=b217be313eed5124","notice_info":{"local_id":"12024110","source":"ActivityPub","repeat_of":"12024008"}},"published":"2026-01-29T17:46:53+00:00","provider":{"objectType":"service","displayName":"GNU social JP","url":"https:\/\/gnusocial.jp\/"},"title":"dalias repeated a notice by aphyr","verb":"share","url":"https:\/\/hachyderm.io\/users\/dalias\/statuses\/115979636558050387\/activity"},{"actor":{"id":"https:\/\/woof.group\/users\/aphyr","displayName":"\u00c9cole des Bro-Arts","status_net":{"avatarLinks":[{"url":"https:\/\/gnusocial.jp\/avatar\/18623-original-tmp20230106170857.webp","rel":"avatar","type":"image\/webp","width":400,"height":400},{"url":"https:\/\/gnusocial.jp\/avatar\/18623-96-20230112144018.webp","rel":"avatar","type":"image\/webp","width":96,"height":96},{"url":"https:\/\/gnusocial.jp\/avatar\/18623-48-20230112144018.webp","rel":"avatar","type":"image\/webp","width":48,"height":48},{"url":"https:\/\/gnusocial.jp\/avatar\/18623-24-20230112144018.webp","rel":"avatar","type":"image\/webp","width":24,"height":24}],"profile_info":{"local_id":"18623"}},"image":{"url":"https:\/\/gnusocial.jp\/avatar\/18623-96-20230112144018.webp","rel":"avatar","type":"image\/webp","width":96,"height":96},"objectType":"person","summary":"Switchy leatherman into bad puns, thick boys, and distributed systems. Purveyor of fine jockstrap selfies. Woof.group admin.Jim Starkey: "Of interest only to third-rate academics a few papers short of a tenure package."Reddit: "would never ever ever hire this degenerate holy shit"Peter Watts: "The most innovative fanfic I've ever read."","url":"https:\/\/woof.group\/@aphyr","portablecontacts_net":{"preferredUsername":"aphyr","displayName":"\u00c9cole des Bro-Arts","note":"Switchy leatherman into bad puns, thick boys, and distributed systems. Purveyor of fine jockstrap selfies. Woof.group admin.Jim Starkey: "Of interest only to third-rate academics a few papers short of a tenure package."Reddit: "would never ever ever hire this degenerate holy shit"Peter Watts: "The most innovative fanfic I've ever read.""}},"content":" Anyway long story short part of what makes older masonry buildings work is that they are *not* well insulated. They're designed to leak heat constantly through the walls, and in healthy structures, this more-or-less maintains the appropriate thermal gradients to prevent condensation and mold, and to dry out the brick to prevent spalling during freeze-thaw cycles.<\/p> Adding insulation to these structures can fuck up that balance. It can be done, but it's tricky!<\/p>","generator":{"id":"tag:gnusocial.jp,2026-06-28:notice-source:ActivityPub","objectType":"application","status_net":{"source_code":"ActivityPub"}},"id":"https:\/\/woof.group\/users\/aphyr\/statuses\/115979522931563254","object":{"id":"https:\/\/woof.group\/users\/aphyr\/statuses\/115979522931563254","objectType":"note","content":" Anyway long story short part of what makes older masonry buildings work is that they are *not* well insulated. They're designed to leak heat constantly through the walls, and in healthy structures, this more-or-less maintains the appropriate thermal gradients to prevent condensation and mold, and to dry out the brick to prevent spalling during freeze-thaw cycles.<\/p> Adding insulation to these structures can fuck up that balance. It can be done, but it's tricky!<\/p>","url":"https:\/\/woof.group\/@aphyr\/115979522931563254","status_net":{"notice_id":null},"inReplyTo":{"objectType":"note","id":"https:\/\/woof.group\/users\/aphyr\/statuses\/115979513397039730","url":"https:\/\/woof.group\/@aphyr\/115979513397039730"}},"to":[{"objectType":"http:\/\/activitystrea.ms\/schema\/1.0\/collection","id":"http:\/\/activityschema.org\/collection\/public"}],"status_net":{"conversation":"tag:gnusocial.jp,2026-01-29:objectType=thread:nonce=b217be313eed5124","notice_info":{"local_id":"12024109","source":"ActivityPub"}},"published":"2026-01-29T17:46:52+00:00","provider":{"objectType":"service","displayName":"GNU social JP","url":"https:\/\/gnusocial.jp\/"},"verb":"post","url":"https:\/\/woof.group\/@aphyr\/115979522931563254"},{"actor":{"id":"https:\/\/hachyderm.io\/users\/inthehands","displayName":"Paul Cantrell","status_net":{"avatarLinks":[{"url":"https:\/\/gnusocial.jp\/avatar\/53259-original-tmp20231130153900.webp","rel":"avatar","type":"image\/webp","width":400,"height":400},{"url":"https:\/\/gnusocial.jp\/avatar\/53259-96-20231130154634.webp","rel":"avatar","type":"image\/webp","width":96,"height":96},{"url":"https:\/\/gnusocial.jp\/avatar\/53259-48-20231130154634.webp","rel":"avatar","type":"image\/webp","width":48,"height":48},{"url":"https:\/\/gnusocial.jp\/avatar\/53259-24-20231130154634.webp","rel":"avatar","type":"image\/webp","width":24,"height":24}],"profile_info":{"local_id":"53259"}},"image":{"url":"https:\/\/gnusocial.jp\/avatar\/53259-96-20231130154634.webp","rel":"avatar","type":"image\/webp","width":96,"height":96},"objectType":"person","summary":"Composer, pianist, programmer, professor, rabble rouser, redheadComputer Science at https:\/\/www.macalester.edu\/mscs\/(Student projects: https:\/\/devgarden.macalester.edu)Artistic Director of https:\/\/newruckus.orgFreelance dev, often with https:\/\/bustout.comMusical troublemaker https:\/\/innig.net\/music\/The heart is the toughest part of the body.Tenderness is in the hands.\u00a0\u2014 Carolyn Forch\u00e9searchable","url":"https:\/\/hachyderm.io\/@inthehands","portablecontacts_net":{"preferredUsername":"inthehands","displayName":"Paul Cantrell","note":"Composer, pianist, programmer, professor, rabble rouser, redheadComputer Science at https:\/\/www.macalester.edu\/mscs\/(Student projects: https:\/\/devgarden.macalester.edu)Artistic Director of https:\/\/newruckus.orgFreelance dev, often with https:\/\/bustout.comMusical troublemaker https:\/\/innig.net\/music\/The heart is the toughest part of the body.Tenderness is in the hands.\u00a0\u2014 Carolyn Forch\u00e9searchable"}},"content":"RT @inthehands Cavity walls (2000+ years old!) allow air circulation within the wall, and damp-proof courses cut off capillary action from the soil.https:\/\/npshistory.com\/publications\/preservation\/masonry-walls-moisture.pdfBut the problem of moisture balance is way, WAY more complex than that. There's vapor pressure and thermal effects for each layer of the wall, and those forces change throughout the year with internal and external heating and moisture.https:\/\/www.wbdg.org\/resources\/moisture-management-concepts is hands-down the best overview I've come across for this problem.","generator":{"id":"tag:gnusocial.jp,2026-06-28:notice-source:ActivityPub","objectType":"application","status_net":{"source_code":"ActivityPub"}},"id":"https:\/\/hachyderm.io\/users\/inthehands\/statuses\/115979560375129602\/activity","object":{"id":"https:\/\/woof.group\/users\/aphyr\/statuses\/115979444561623570","objectType":"note","content":" Incidentally, one of the cool\/frustrating things I've learned after a decade of living in various older masonry buildings is that you actually *can't* insulate them very much without fucking up the moisture balance.<\/p> Every masonry wall takes on water through leaks and the natural porosity of the brick\/stone. That moisture has to leave the wall cavity through open joints or weeps. If you've ever seen those little pieces of rope hanging off a brick building, they're to let water wick out!<\/p>","url":"https:\/\/woof.group\/@aphyr\/115979444561623570","status_net":{"notice_id":null}},"to":[{"objectType":"http:\/\/activitystrea.ms\/schema\/1.0\/collection","id":"http:\/\/activityschema.org\/collection\/public"}],"status_net":{"conversation":"tag:gnusocial.jp,2026-01-29:objectType=thread:nonce=b217be313eed5124","notice_info":{"local_id":"12024009","source":"ActivityPub","repeat_of":"12024007"}},"published":"2026-01-29T17:27:33+00:00","provider":{"objectType":"service","displayName":"GNU social JP","url":"https:\/\/gnusocial.jp\/"},"title":"inthehands repeated a notice by aphyr","verb":"share","url":"https:\/\/hachyderm.io\/users\/inthehands\/statuses\/115979560375129602\/activity"},{"actor":{"id":"https:\/\/woof.group\/users\/aphyr","displayName":"\u00c9cole des Bro-Arts","status_net":{"avatarLinks":[{"url":"https:\/\/gnusocial.jp\/avatar\/18623-original-tmp20230106170857.webp","rel":"avatar","type":"image\/webp","width":400,"height":400},{"url":"https:\/\/gnusocial.jp\/avatar\/18623-96-20230112144018.webp","rel":"avatar","type":"image\/webp","width":96,"height":96},{"url":"https:\/\/gnusocial.jp\/avatar\/18623-48-20230112144018.webp","rel":"avatar","type":"image\/webp","width":48,"height":48},{"url":"https:\/\/gnusocial.jp\/avatar\/18623-24-20230112144018.webp","rel":"avatar","type":"image\/webp","width":24,"height":24}],"profile_info":{"local_id":"18623"}},"image":{"url":"https:\/\/gnusocial.jp\/avatar\/18623-96-20230112144018.webp","rel":"avatar","type":"image\/webp","width":96,"height":96},"objectType":"person","summary":"Switchy leatherman into bad puns, thick boys, and distributed systems. Purveyor of fine jockstrap selfies. Woof.group admin.Jim Starkey: "Of interest only to third-rate academics a few papers short of a tenure package."Reddit: "would never ever ever hire this degenerate holy shit"Peter Watts: "The most innovative fanfic I've ever read."","url":"https:\/\/woof.group\/@aphyr","portablecontacts_net":{"preferredUsername":"aphyr","displayName":"\u00c9cole des Bro-Arts","note":"Switchy leatherman into bad puns, thick boys, and distributed systems. Purveyor of fine jockstrap selfies. Woof.group admin.Jim Starkey: "Of interest only to third-rate academics a few papers short of a tenure package."Reddit: "would never ever ever hire this degenerate holy shit"Peter Watts: "The most innovative fanfic I've ever read.""}},"content":" It's a \"wearing two coats at my desk and still shivering\" kind of winter because I'm stubborn about trying to rely on the heat pumps as much as possible. So mad that I asked for cold-climate systems and they gave me this nonsense.<\/p> When I get out from under this house repair nightmare and finances recover a bit I want to hire, like... someone with a FLIR drone to fly around the home, figure out all the places where it's leaking heat, and help insulate\/seal them.<\/p>","generator":{"id":"tag:gnusocial.jp,2026-06-28:notice-source:ActivityPub","objectType":"application","status_net":{"source_code":"ActivityPub"}},"id":"https:\/\/woof.group\/users\/aphyr\/statuses\/115979419132437617","object":{"id":"https:\/\/woof.group\/users\/aphyr\/statuses\/115979419132437617","objectType":"note","content":" It's a \"wearing two coats at my desk and still shivering\" kind of winter because I'm stubborn about trying to rely on the heat pumps as much as possible. So mad that I asked for cold-climate systems and they gave me this nonsense.<\/p> When I get out from under this house repair nightmare and finances recover a bit I want to hire, like... someone with a FLIR drone to fly around the home, figure out all the places where it's leaking heat, and help insulate\/seal them.<\/p>","url":"https:\/\/woof.group\/@aphyr\/115979419132437617","status_net":{"notice_id":null}},"to":[{"objectType":"http:\/\/activitystrea.ms\/schema\/1.0\/collection","id":"http:\/\/activityschema.org\/collection\/public"}],"status_net":{"conversation":"tag:gnusocial.jp,2026-01-29:objectType=thread:nonce=b217be313eed5124","notice_info":{"local_id":"12024006","source":"ActivityPub"}},"published":"2026-01-29T17:27:33+00:00","provider":{"objectType":"service","displayName":"GNU social JP","url":"https:\/\/gnusocial.jp\/"},"verb":"post","url":"https:\/\/woof.group\/@aphyr\/115979419132437617"},{"actor":{"id":"https:\/\/woof.group\/users\/aphyr","displayName":"\u00c9cole des Bro-Arts","status_net":{"avatarLinks":[{"url":"https:\/\/gnusocial.jp\/avatar\/18623-original-tmp20230106170857.webp","rel":"avatar","type":"image\/webp","width":400,"height":400},{"url":"https:\/\/gnusocial.jp\/avatar\/18623-96-20230112144018.webp","rel":"avatar","type":"image\/webp","width":96,"height":96},{"url":"https:\/\/gnusocial.jp\/avatar\/18623-48-20230112144018.webp","rel":"avatar","type":"image\/webp","width":48,"height":48},{"url":"https:\/\/gnusocial.jp\/avatar\/18623-24-20230112144018.webp","rel":"avatar","type":"image\/webp","width":24,"height":24}],"profile_info":{"local_id":"18623"}},"image":{"url":"https:\/\/gnusocial.jp\/avatar\/18623-96-20230112144018.webp","rel":"avatar","type":"image\/webp","width":96,"height":96},"objectType":"person","summary":"Switchy leatherman into bad puns, thick boys, and distributed systems. Purveyor of fine jockstrap selfies. Woof.group admin.Jim Starkey: "Of interest only to third-rate academics a few papers short of a tenure package."Reddit: "would never ever ever hire this degenerate holy shit"Peter Watts: "The most innovative fanfic I've ever read."","url":"https:\/\/woof.group\/@aphyr","portablecontacts_net":{"preferredUsername":"aphyr","displayName":"\u00c9cole des Bro-Arts","note":"Switchy leatherman into bad puns, thick boys, and distributed systems. Purveyor of fine jockstrap selfies. Woof.group admin.Jim Starkey: "Of interest only to third-rate academics a few papers short of a tenure package."Reddit: "would never ever ever hire this degenerate holy shit"Peter Watts: "The most innovative fanfic I've ever read.""}},"content":" Incidentally, one of the cool\/frustrating things I've learned after a decade of living in various older masonry buildings is that you actually *can't* insulate them very much without fucking up the moisture balance.<\/p> Every masonry wall takes on water through leaks and the natural porosity of the brick\/stone. That moisture has to leave the wall cavity through open joints or weeps. If you've ever seen those little pieces of rope hanging off a brick building, they're to let water wick out!<\/p>","generator":{"id":"tag:gnusocial.jp,2026-06-28:notice-source:ActivityPub","objectType":"application","status_net":{"source_code":"ActivityPub"}},"id":"https:\/\/woof.group\/users\/aphyr\/statuses\/115979444561623570","object":{"id":"https:\/\/woof.group\/users\/aphyr\/statuses\/115979444561623570","objectType":"note","content":" Incidentally, one of the cool\/frustrating things I've learned after a decade of living in various older masonry buildings is that you actually *can't* insulate them very much without fucking up the moisture balance.<\/p> Every masonry wall takes on water through leaks and the natural porosity of the brick\/stone. That moisture has to leave the wall cavity through open joints or weeps. If you've ever seen those little pieces of rope hanging off a brick building, they're to let water wick out!<\/p>","url":"https:\/\/woof.group\/@aphyr\/115979444561623570","status_net":{"notice_id":null},"inReplyTo":{"objectType":"note","id":"https:\/\/woof.group\/users\/aphyr\/statuses\/115979419132437617","url":"https:\/\/woof.group\/@aphyr\/115979419132437617"}},"to":[{"objectType":"http:\/\/activitystrea.ms\/schema\/1.0\/collection","id":"http:\/\/activityschema.org\/collection\/public"}],"status_net":{"conversation":"tag:gnusocial.jp,2026-01-29:objectType=thread:nonce=b217be313eed5124","notice_info":{"local_id":"12024007","source":"ActivityPub"}},"published":"2026-01-29T17:27:32+00:00","provider":{"objectType":"service","displayName":"GNU social JP","url":"https:\/\/gnusocial.jp\/"},"verb":"post","url":"https:\/\/woof.group\/@aphyr\/115979444561623570"},{"actor":{"id":"https:\/\/woof.group\/users\/aphyr","displayName":"\u00c9cole des Bro-Arts","status_net":{"avatarLinks":[{"url":"https:\/\/gnusocial.jp\/avatar\/18623-original-tmp20230106170857.webp","rel":"avatar","type":"image\/webp","width":400,"height":400},{"url":"https:\/\/gnusocial.jp\/avatar\/18623-96-20230112144018.webp","rel":"avatar","type":"image\/webp","width":96,"height":96},{"url":"https:\/\/gnusocial.jp\/avatar\/18623-48-20230112144018.webp","rel":"avatar","type":"image\/webp","width":48,"height":48},{"url":"https:\/\/gnusocial.jp\/avatar\/18623-24-20230112144018.webp","rel":"avatar","type":"image\/webp","width":24,"height":24}],"profile_info":{"local_id":"18623"}},"image":{"url":"https:\/\/gnusocial.jp\/avatar\/18623-96-20230112144018.webp","rel":"avatar","type":"image\/webp","width":96,"height":96},"objectType":"person","summary":"Switchy leatherman into bad puns, thick boys, and distributed systems. Purveyor of fine jockstrap selfies. Woof.group admin.Jim Starkey: "Of interest only to third-rate academics a few papers short of a tenure package."Reddit: "would never ever ever hire this degenerate holy shit"Peter Watts: "The most innovative fanfic I've ever read."","url":"https:\/\/woof.group\/@aphyr","portablecontacts_net":{"preferredUsername":"aphyr","displayName":"\u00c9cole des Bro-Arts","note":"Switchy leatherman into bad puns, thick boys, and distributed systems. Purveyor of fine jockstrap selfies. Woof.group admin.Jim Starkey: "Of interest only to third-rate academics a few papers short of a tenure package."Reddit: "would never ever ever hire this degenerate holy shit"Peter Watts: "The most innovative fanfic I've ever read.""}},"content":" Cavity walls (2000+ years old!) allow air circulation within the wall, and damp-proof courses cut off capillary action from the soil.<\/p> https:\/\/npshistory.com\/publications\/preservation\/masonry-walls-moisture.pdf<\/a><\/p> But the problem of moisture balance is way, WAY more complex than that. There's vapor pressure and thermal effects for each layer of the wall, and those forces change throughout the year with internal and external heating and moisture.<\/p> https:\/\/www.wbdg.org\/resources\/moisture-management-concepts<\/a> is hands-down the best overview I've come across for this problem.<\/p>","generator":{"id":"tag:gnusocial.jp,2026-06-28:notice-source:ActivityPub","objectType":"application","status_net":{"source_code":"ActivityPub"}},"id":"https:\/\/woof.group\/users\/aphyr\/statuses\/115979513397039730","object":{"id":"https:\/\/woof.group\/users\/aphyr\/statuses\/115979513397039730","objectType":"note","content":" Cavity walls (2000+ years old!) allow air circulation within the wall, and damp-proof courses cut off capillary action from the soil.<\/p>