Victorian Building Techniques Basics
I stood in the Living Room a bit dumbfounded today by the damage a little curiosity can cause. I remember a month ago thinking to myself “I should help fix up The Laurels. A little paint wouldn’t hurt.”
Oh what a deep rabbit hole I fell into.
A “little paint”…
…turned into “but first…remove the wallpaper because it is ugly…”
…which turned into “and then remove the painted over, varnished Victorian wallpaper that seems to be WELDED to the walls underneath that because: OCD”…
…which turned into “it’s not coming off…”
…which turned into “Google: how can I get it off?”…
…which turned into a month long cram course on Victorian building techniques while researching why skim coating (the suggested method of dealing with less than perfect walls) antique lime plaster walls is a bad idea…
…and finally me, going on my fourth week of slowly scraping off… piece by 2 cm wide piece… the painted over, varnished Victorian wallpaper from the wall to it was welded onto 130 years earlier. Frantically. Because the house was suffocating and COULD NOT BREATHE!!!
What is all this talk about breathing in old houses anyway? Basically it boils down to two things. 1.) Capillary action and 2.) Surface Area.
Houses built today which block water through impermeable materials: Portland Cement (the official name of cement), Tyvek sheeting, vinyl siding, PVC windows, latex caulking, insulation, insulation, insulation! Water ain’t going nowhere near my interior, yo.
All of these materials exist thanks to technology, technologies that either weren’t around or not commonly used in buildings 130 years ago when homes like The Laurels were built. Tyvek was discovered by a DuPont scientist in 1955. Early versions of Portland Cement, or “Artificial Lime” were created in 1756 but the recipe wasn’t perfected and standardized until 1878. PVC was discovered accidentally in 1838 but not patented (you can read that as “backed with monetary investment for applicable purposes”) until 1913.
To contrast this, old houses are made to move water around via capillary action. Much like our bodies, liquid is constantly moving in and out, up and down, through the materials that old buildings are made out of. Water from the ground, humidity and precipitation would move through the structure until it reached a surface where it was able to evaporate…leaving no trace of it’s presence known. At least, that’s how it works in the properly crafted, unadulterated structures our fore fathers bequeathed to us.
Remember this awesome experiment from when we were kids?
The coffee filter is the walls of your antique house. The water is the money in your wallet, it moves up and away from your bank account through capillary action.
That’s not right. Let’s look at how it really works through a series of hypothetical experiments:
Experiment 1: Permeable Objects
The coffee filter is the walls: clay bricks, lime mortar, wooden lathe, horsehair, goat hair, sheep wool and lime plaster. The water in the cup is the naturally occurring ground water, water from the air, rain water, etc. that your walls are designed to deal with.
If you put any of these items in water and wait a bit you’ll see that they will absorb water. Pull it out, dry it off and it will still be moist… for a while until what? Yep: until the water evaporates and it becomes dry once again.
These are your permeable materials, meaning materials that allow liquids or gases to pass through it. If you replace an untreated wood lathe for the coffee filter in the experiment above you will see a similar response as the water is pulled from the cup and moves up the stick. Permeable coffee filter. Permeable wood stick lathe.
Result: Permeable Objects absorb and move water.
Experiment 2: Impermeable Objects
Put a piece of PVC, cement or Tyvek in water and after you dry off the surface moisture it will still be dry. They didn’t absorb water. These are impermeable.
Result: Impermeable Objects do not allow liquids to pass through.
Experiment 3: Make a Permeable Object Impermeable
Now…let’s say you paint your lathe stick entirely with one of the nice modern acrylic or oil based paints on the market today. Go ahead; all six sides, don’t be shy. Now if you did it right and gave it a right good coating you have just created a non-permeable material from a permeable material. The water won’t touch it as long as the barrier remains intact. Congratulations.
Result: Impermeable coverings block water from reaching permeable objects.
Let’s look at another experiment:
Experiment 4: Make a Glass of Water Evaporate
If we just sit a glass of water out for a few days, the water level will drop. This is because the water evaporates. Wikipedia explains why better than I could:
Evaporation is a type of vaporization of a liquid that occurs from the surface of a liquid into a gaseous phase that is not saturated with the evaporating substance. ~Wikipedia
The thing to focus on here is “the surface of a liquid”. Let’s see how increasing the surface of a liquid aids in evaporation. Add a second cup with the same amount of liquid as the first cup. This time stick your wood lathe in again, half covered. Which cup will lose all of its water to evaporation first? The one with the wood lathe. We’ve expanded the surface area of the water by augmenting it with a permeable material.
Result: Permeable objects assist with the rate of evaporation.
Experiment 5: Make a Permeable Object Partially Impermeable
Let’s try another experiment: paint just the top half of the stick…the part sticking out of the water. The top half is impermeable, but the bottom half is still permeable. Stick the permeable half in the water. What happens now? The water is being drawn up the stick but has no where to go. Eventually the stick becomes water logged but since half is underwater and half is covered by an impermeable layer of paint the water has no where to go. It can’t evaporate from the stick into the less moist air around it. It stays wet. And it rots.
Result: Partial Impermeable coverings block water from escaping permeable objects.
See where I am going with this? When we start putting layers of impermeable, modern building materials overtop of the permeable materials of our forefathers we start to disrupt the system. If the water cannot move anywhere, things begin to rot.
“Ok,” you say “Just put an impermeable layer over the permeable layer. Problem solved.”
Except not. Even if you could surround a permeable object on all sides (impossible with wood beams or bricks which are butted up against something else, somewhere creating a bridge for moisture), you would still need to:
1.) Remove ALL the moisture already inside the object before coating it. It’s virtually impossible. Moisture builds up behind the impermeable layer and tried to escape, pushing the layer out of the way in the process. Moisture trumps all. Think of pealing paint and wallpapers. You can’t win against water.
2.) Keep the impermeable layer completely intact…forever. Nail holes, nicks, scratches, bumps, hairline fractures caused by the layer itself expanding and contracting in cold and hot environments: the layer will be breached and as soon as that happens water starts to get in via the natural water in the air.
But there are other problems that can occur as well as just rotting materials due to water stagnation. With so many things connected, as moisture builds up in an area it begins to move to less saturated surrounding areas…capillary action. In an unadulterated house this process is distributed equally over all surfaces: interior walls, exterior walls, floor, ceilings, roofs. But what happens when we start adding impermeable materials?
PVC damp proof membranes under the floor trap moisture, but it doesn’t just sit there. If it did eventually pools of water would collect and erode whatever it is sitting on…because that is the nature of water: the force of eternal change. Moisture moves outward via capillary action. As it does it will find a nice, permeable object get into: your walls. The same walls that are already handling the moisture levels it was designed to deal with originally. Now it gets to also handle the load of the water from the cellar floor.
It handles it with grace, moving the extra water upwards, expanding the amount of wall space needed for evaporation. But then it happens: a brick needs repointed (the mortar replaced around it). Instead of permeable lime mortar, we use Portland Cement. Now the water can’t travel upwards anymore. Some of it moves sideways and increases the moisture levels of the wall in that area…requiring more area for proper evaporation. Some of it doesn’t.
Inside lime plaster is covered with modern impermeable acrylic and oil paints, or worse: covered with vapor boards, impermeable paneling or vinyl wallpapers. Plaster is skim coated and patched with modern day mixtures. Chimneys are closed up, sometimes unvented. Woods are varnished with modern mixes instead of breathable waxes and their crevices are sealed. Sash windows are replaced with PVC. All of this displacing water to areas already stressed with their new requirements.
So it all heads towards the walls… it sits in the bricks which, not able to evaporate fast enough turn damp. Then it freezes, and it thaws, and freezes again and soon the protective faces of the bricks break away and the rain enters immediately and heads towards the basement.
Then we add rubber backed carpet pads and cement screed floors…trapping whatever moisture the walls are emitting in the floors below right where it is. We block up windows, coal chutes, air vents in the name of energy conservation so the air can’t remove some of it and the sun is blocked from shining it’s antibacterial and mould properties in.
Suddenly the house is sick. It’s not able to breathe. A damp that can’t be shook sets in and all the snake oil salesmen peddling their DPC wares arrive with their quick fixes to symptoms that are easily remedied otherwise.
So you find yourself: day 35 of a 2 day paint job chiseling every last square of impermeable chemical cocktail from the walls (after pulling up every last piece of carpet to check for rubber and opening basement windows that were bricked shut ages ago) and things begin to make sense: The salt deposits on the outside of the house corresponding to the unvented blocked up chimney, the wet plaster trail you can now follow back 8 feet to the vapor backed sheet rock glued to original lime plaster walls.
So you continue chipping away, and expand your project timeline from 2 months to 3 years because the house grew on you and now you can speak her language and it simply must be done, and it must be done right.
And you wonder: if a life full of plastics and artificials can do this to the body of a house, what could it be doing to a body of a human?