I worked on many historical buildings during a 50 year career in architecture and owned four houses spanning from the Georgian to the Edwardian periods. One was an old Victorian farmhouse in the Scottish Borders that I purchased from the Duke of Buccleuch. The previous occupants was a tenant farmer, Geordie Howieson who in the 49 years he occupied the place hadn't put a lick of paint on a door so the house was dilapidated but hadn't been spoilt by good intentions. Very much in its original condition, it was not even equipped with electricity which I had to lay in from the nearest power line 3/4 miles away.
In the days of plaster on lath, lathing was its own separate trade, distinct from the plasterer, and the speed at which a good lather could split the chestnut and rough out a wall was remarkable. Of course the lath was not strong enough to carry heavy paintings or tapestries which is why older houses sported a picture a couple of feet below ceiling level, behind which was structural timber strong enough to carry wall hangings. Wainscoting was also popular at the time.
The roughing coat of plaster was invariably reinforced with horsehair. Those were pre motorised transport days and horses abounded in villages, cities and on farms so there was no shortage of the material. Indeed, the decline in the population of horses as a result of industrialisation is one reason that alternative technologies were popularised. Much like fibre reinforced concrete, the hair provided a degree of structural integrity to the plaster and left the surface just rough enough to provide a key for the topcoat.
In most of the better (i.e. surviving) plaster-on-lath buildings the walls were lined, mostly with paper but silk or other fabrics could be used in the better buildings. Paper lining is still a common technique to disguise poor plasterwork in older buildings, the weight of paper being dictated by how distressed the plaster is. There's an excellent book called the Care and Conservation of Georgian Houses, authored by Roy Milne, a former colleague and excellent architect, who I worked with when I practiced in Edinburgh.
As someone who worked in property renovation in for 10 years, I used to marvel at the labour required not just to plaster the walls and ceilings of old buildings but to install the lathe backing.
For a 5m x 5m x 2.5m high room that's 75sqm of lathes. With each one being approximately 40mm wide - let's say 50mm with the gap - you're looking at 1000 lineal metres (one whole kilometre!) of timber for each room, all cut and nailed by hand. I get tired just thinking about it.
I feel silly for not taking into account laths when discussing the labor expense! I would have assumed that laths are mass produced, but that might not be true given the potential lack of uniformity with regards to stud spacing.
On tear outs, I marvel at the amount of wood lath. What's awful is it was old growth material absent knots or defects...prime AAA quality by today's standards.
We recently hung an entire art show of more than 40 paintings in one (long) afternoon using a new gallery-friendly picture rail system. Such systems are as slick as can be and nearly invisible. Much easier than nails or anchor bolts.
Art galleries heavily rely on rail systems for hanging art, although they tend to have modern amenities (such as the ability to slide laterally) that are missing from residential picture rail moulding.
I felt so seen by this, as someone long battling with the challenges and repairs of a lath and plaster house.
I have composed love letters to drywall, now that I realize how good I had it in previous houses.
Also: my father (construction background since the 1980s) tells me that most modern drywall is not made of straight gypsum any more. It has a polymer (that is, a type of plastic?) mixed in with the gypsum, which makes it sag-resistant, moisture-resistant, and not as heavy as the original variety. Also... less recyclable, and more plastic in landfills, if that's the case.
I’ve Ben a residential contractor for years and have hung and hired others to hang and finish quite a pile of drywall. The biggest drawback is that corners and joints are only reinforced with paper tape in a water-based compound and crack easily with the normal movement of wooden construction.
My tile/plaster guy came from a family of plasterers, true craftsman. We no longer use wood lath but 3/8” drywall with the rougher back side exposed for better adhesion. Corners and seems are reinforced with expanded steel lath which when buried in plaster resist cracking much better than paper. The ultimate finish from hand polished plaster is vastly superior to drywall. The cost is quadruple and of course the availability of skilled artisans is practically nil.
I also wanted to highlight a transitional period that in Ohio was from post WWII through the fifties, the precursor to drywall, rock lath. The sheets were 2’ x 4’ x 3/8” thick. Seams and corners were reinforced with expanded steel lath. Demolition is a nightmare, even after 75 years the material is incredibly durable. And of course the level of skill involved in mixing and installing multiple coats by hand is costly.
This would have been nice to read when I moved into my early 1900s house which has had some renovations, which leaves us with a combination of drywall and lathe-plaster. It's been a trial by fire experience
The house we rent, built in the 1870s, has plaster walls and picture rails; hanging things is indeed a pain, although once done it seems largely fine. I don't know how much asbestos is in here —I'd believe everything, this is New Orleans— but during an HVAC disaster we had an open hole to the humid and hot outdoors for a couple of weeks; when we noticed a bit of mold and had a tech look, he marveled that we didn't have a full-on black mold catastrophe. I assume we owe that to the plaster, and the fact that the house was designed before builders expected sealing or climate control at all.
Great post! I'll try not to think about the asbestos!!!
I love this. I actually have been following a lot of "aesthetic" accounts that complain about modern construction and post beautiful photos of older quaint homes. I also live in a new-build faux Craftsman but can't help but admire the homes and neighborhood in the original part of town.
I was curious if there were any alternatives to dry wall that might look better, and there is rammed earth, but it's not very practical. And went down a similar rabbit hole to discover plaster and lathe is too flammable.
So I guess the only flaw of dry wall is that it is so abundant that is now universal and manufactured so perfectly and the construction process so efficient that it creates too much of the same for us to appreciate it.
YASSine this was a fun article to read. Actually reminded me of Scott a bit, as well as Roman Mars of 99% Invisible fame. Excellent, thank you! My one quibble is at the end: the sources you link to for e.g. “smart drywall” are seemingly purely hypothetical? I don’t see any evidence of actual production of “smart” drywall. If you have it, please share so I can connect my walls to wifi like I’ve always dreamed about 😘
This article was very timely as i recently knocked down a plaster and lath wall to expand the landing and put a stud/plasterboard wall up further back. Plasterer finished it up over the weekend and now very happy.
Also good to know I'm not the only one that has had unexpected trouble hanging frames on P&L walls...
Plaster was not gypsum; it was lime based, usually with horsehair as a reinforcement. Gypsum was sometimes used as a finishing coat or as part of the gauging plaster. And, asbestos of course, although asbestos was not used in all plaster and it was used as a reinforcer, with fire retardant characteristics an added bonus.
Gypsum blue board was originally a replacement for wood lath and the transition to thinset coats of lime based plaster. The jump was not straight from wood lath to 4x8 gypsum sheets. Someone figured why not take these 16x32 pieces of blue gypsum and make them big.
Durabond 90, 45, or 20...hot set mud for drywall taping and repairs works fantastically for repairing old plaster. The lime plaster purists say no, it's gotta be lime plaster. They're wrong.
I'm happy to be corrected, but I've seen several sources explaining that plaster is most often composed of gypsum (as well as lime or cement as alternative options). Is that mistaken?
It depends on how far back you go. As I said, gypsum was sometimes used as part of the gauged plaster finish coat as an additive and drying agent. The stuff in your pics is lime based horse hair plaster. Gypsum began being introduced and eventually took over from lime based material because lime takes more time and energy. And of course, being the internet, I'm sure someone will pop up and say I'm wrong.
Traditional plaster, as you probably know, was actually two coats, the scratch coat (no gypsum, basically lime cement) and the finish coat, with the finish coat in later periods being lime and gypsum and called "gauged" plaster. Again, depending on time and location, sometimes just pure lime. Maybe some areas used pure gypsum, but I've never hear of it nor seen it.
Gypsum was often used in pulled moldings and interior decorative details, so that throws some other considerations into the mix.
I've done material analysis on a LOT of plaster and it most often is lime. That doesn't mean it's all lime all the time in all locations though. People built with the materials they could get.
If you got waaaay back, gypsum was used in ancient Egypt, so it's not like gypsum is a new material.
Also, I'm a lime freak. I'm an olde guy, and an old building guy. The miracle of lime is not known enough. People need to understand lime plaster and lime mortars.
Check out limeworks.us. There's a mountain of information on lime and its uses in old buildings.
Not boring. Fascinating. Thanks.
Well this was wonderful. Thanks. Nice to know the context we live within. And to appreciate all the workers and inventors who made our lives better.
Nice article.
I worked on many historical buildings during a 50 year career in architecture and owned four houses spanning from the Georgian to the Edwardian periods. One was an old Victorian farmhouse in the Scottish Borders that I purchased from the Duke of Buccleuch. The previous occupants was a tenant farmer, Geordie Howieson who in the 49 years he occupied the place hadn't put a lick of paint on a door so the house was dilapidated but hadn't been spoilt by good intentions. Very much in its original condition, it was not even equipped with electricity which I had to lay in from the nearest power line 3/4 miles away.
In the days of plaster on lath, lathing was its own separate trade, distinct from the plasterer, and the speed at which a good lather could split the chestnut and rough out a wall was remarkable. Of course the lath was not strong enough to carry heavy paintings or tapestries which is why older houses sported a picture a couple of feet below ceiling level, behind which was structural timber strong enough to carry wall hangings. Wainscoting was also popular at the time.
The roughing coat of plaster was invariably reinforced with horsehair. Those were pre motorised transport days and horses abounded in villages, cities and on farms so there was no shortage of the material. Indeed, the decline in the population of horses as a result of industrialisation is one reason that alternative technologies were popularised. Much like fibre reinforced concrete, the hair provided a degree of structural integrity to the plaster and left the surface just rough enough to provide a key for the topcoat.
In most of the better (i.e. surviving) plaster-on-lath buildings the walls were lined, mostly with paper but silk or other fabrics could be used in the better buildings. Paper lining is still a common technique to disguise poor plasterwork in older buildings, the weight of paper being dictated by how distressed the plaster is. There's an excellent book called the Care and Conservation of Georgian Houses, authored by Roy Milne, a former colleague and excellent architect, who I worked with when I practiced in Edinburgh.
As someone who worked in property renovation in for 10 years, I used to marvel at the labour required not just to plaster the walls and ceilings of old buildings but to install the lathe backing.
For a 5m x 5m x 2.5m high room that's 75sqm of lathes. With each one being approximately 40mm wide - let's say 50mm with the gap - you're looking at 1000 lineal metres (one whole kilometre!) of timber for each room, all cut and nailed by hand. I get tired just thinking about it.
I feel silly for not taking into account laths when discussing the labor expense! I would have assumed that laths are mass produced, but that might not be true given the potential lack of uniformity with regards to stud spacing.
They probably would have been like most construction lumber - supplied in standard lengths then cut to size onsite.
Anyway, it's all good. Underestimating time and effort is standard practise in construction. ;)
On tear outs, I marvel at the amount of wood lath. What's awful is it was old growth material absent knots or defects...prime AAA quality by today's standards.
We recently hung an entire art show of more than 40 paintings in one (long) afternoon using a new gallery-friendly picture rail system. Such systems are as slick as can be and nearly invisible. Much easier than nails or anchor bolts.
Art galleries heavily rely on rail systems for hanging art, although they tend to have modern amenities (such as the ability to slide laterally) that are missing from residential picture rail moulding.
I felt so seen by this, as someone long battling with the challenges and repairs of a lath and plaster house.
I have composed love letters to drywall, now that I realize how good I had it in previous houses.
Also: my father (construction background since the 1980s) tells me that most modern drywall is not made of straight gypsum any more. It has a polymer (that is, a type of plastic?) mixed in with the gypsum, which makes it sag-resistant, moisture-resistant, and not as heavy as the original variety. Also... less recyclable, and more plastic in landfills, if that's the case.
I’ve Ben a residential contractor for years and have hung and hired others to hang and finish quite a pile of drywall. The biggest drawback is that corners and joints are only reinforced with paper tape in a water-based compound and crack easily with the normal movement of wooden construction.
My tile/plaster guy came from a family of plasterers, true craftsman. We no longer use wood lath but 3/8” drywall with the rougher back side exposed for better adhesion. Corners and seems are reinforced with expanded steel lath which when buried in plaster resist cracking much better than paper. The ultimate finish from hand polished plaster is vastly superior to drywall. The cost is quadruple and of course the availability of skilled artisans is practically nil.
I also wanted to highlight a transitional period that in Ohio was from post WWII through the fifties, the precursor to drywall, rock lath. The sheets were 2’ x 4’ x 3/8” thick. Seams and corners were reinforced with expanded steel lath. Demolition is a nightmare, even after 75 years the material is incredibly durable. And of course the level of skill involved in mixing and installing multiple coats by hand is costly.
Thanks for the great post!
This would have been nice to read when I moved into my early 1900s house which has had some renovations, which leaves us with a combination of drywall and lathe-plaster. It's been a trial by fire experience
The house we rent, built in the 1870s, has plaster walls and picture rails; hanging things is indeed a pain, although once done it seems largely fine. I don't know how much asbestos is in here —I'd believe everything, this is New Orleans— but during an HVAC disaster we had an open hole to the humid and hot outdoors for a couple of weeks; when we noticed a bit of mold and had a tech look, he marveled that we didn't have a full-on black mold catastrophe. I assume we owe that to the plaster, and the fact that the house was designed before builders expected sealing or climate control at all.
Great post! I'll try not to think about the asbestos!!!
I love this. I actually have been following a lot of "aesthetic" accounts that complain about modern construction and post beautiful photos of older quaint homes. I also live in a new-build faux Craftsman but can't help but admire the homes and neighborhood in the original part of town.
I was curious if there were any alternatives to dry wall that might look better, and there is rammed earth, but it's not very practical. And went down a similar rabbit hole to discover plaster and lathe is too flammable.
So I guess the only flaw of dry wall is that it is so abundant that is now universal and manufactured so perfectly and the construction process so efficient that it creates too much of the same for us to appreciate it.
This was really interesting—thank you!
Unexpectedly fascinating!
YASSine this was a fun article to read. Actually reminded me of Scott a bit, as well as Roman Mars of 99% Invisible fame. Excellent, thank you! My one quibble is at the end: the sources you link to for e.g. “smart drywall” are seemingly purely hypothetical? I don’t see any evidence of actual production of “smart” drywall. If you have it, please share so I can connect my walls to wifi like I’ve always dreamed about 😘
Entertaining and informative post. Thanks for the enlightenment (in both senses :-)
This article was very timely as i recently knocked down a plaster and lath wall to expand the landing and put a stud/plasterboard wall up further back. Plasterer finished it up over the weekend and now very happy.
Also good to know I'm not the only one that has had unexpected trouble hanging frames on P&L walls...
Fun article...a few quibbles....
Plaster was not gypsum; it was lime based, usually with horsehair as a reinforcement. Gypsum was sometimes used as a finishing coat or as part of the gauging plaster. And, asbestos of course, although asbestos was not used in all plaster and it was used as a reinforcer, with fire retardant characteristics an added bonus.
Gypsum blue board was originally a replacement for wood lath and the transition to thinset coats of lime based plaster. The jump was not straight from wood lath to 4x8 gypsum sheets. Someone figured why not take these 16x32 pieces of blue gypsum and make them big.
Durabond 90, 45, or 20...hot set mud for drywall taping and repairs works fantastically for repairing old plaster. The lime plaster purists say no, it's gotta be lime plaster. They're wrong.
I'm happy to be corrected, but I've seen several sources explaining that plaster is most often composed of gypsum (as well as lime or cement as alternative options). Is that mistaken?
It depends on how far back you go. As I said, gypsum was sometimes used as part of the gauged plaster finish coat as an additive and drying agent. The stuff in your pics is lime based horse hair plaster. Gypsum began being introduced and eventually took over from lime based material because lime takes more time and energy. And of course, being the internet, I'm sure someone will pop up and say I'm wrong.
Traditional plaster, as you probably know, was actually two coats, the scratch coat (no gypsum, basically lime cement) and the finish coat, with the finish coat in later periods being lime and gypsum and called "gauged" plaster. Again, depending on time and location, sometimes just pure lime. Maybe some areas used pure gypsum, but I've never hear of it nor seen it.
Gypsum was often used in pulled moldings and interior decorative details, so that throws some other considerations into the mix.
I've done material analysis on a LOT of plaster and it most often is lime. That doesn't mean it's all lime all the time in all locations though. People built with the materials they could get.
If you got waaaay back, gypsum was used in ancient Egypt, so it's not like gypsum is a new material.
Also, I'm a lime freak. I'm an olde guy, and an old building guy. The miracle of lime is not known enough. People need to understand lime plaster and lime mortars.
Check out limeworks.us. There's a mountain of information on lime and its uses in old buildings.