Friday, November 21, 2014

Connecting with stone





A rough-made stone base links this 1913 wooden bungalow to its rocky upland site
 
When I said ‘yes’ to buying an old house built on a stone foundation, I had no idea of the new headaches I was agreeing to as a result. We tend to see things made of stone as permanent (part of their charm) whereas materials like wood we more easily accept need periodic maintenance. But stone needs attention too, only over much longer intervals if it's been well done originally. And as many do with houses, I went for the whole enchilada without close examination of the parts, then gradually awoke to the realities of the work needed to stabilize and repair.


As I settled into my new home, I began noticing among other things that its sturdy stone base was in fact sporting several breaches. It turns out that seventy-five years of exposure to weather with minimal maintenance will do that to a foundation held together by lime mortar. The materials comprising it were ordinary, mostly from the site itself, and randomly set without conscious patterning or coursing. A lot of different shapes and sizes had gone into that foundation, with a crazy-quilt of seams among them. Here and there enlarging cracks offered openings to the shallow crawl space behind them. Earth shifting, courtesy of forces like tree root expansion or earthquake action, plus the effects of freeze-thaw cycles, can crack and degrade even sturdy walls over time. In some spots the base of the wall was actually coming unstuck and starting to dilapidate.


As roots grow and expand, they raise the soil above them, easily cracking rock walls
This tree trunk has broken the section in front of it, now needing repair and likely to fail again

I also began noticing signs of slapdash fix-ups, careless work that had simply smeared mortar across the face of the stone. These sloppy repairs (what the English call bodges) leapt to the eye like  carbuncles. So of course my first thought as a naieve homeowner was to involve someone skilled (‘call the plumber!’) to address the problem.


But back then I didn’t know anything about stone masonry, so I talked a bricklayer I’d hired to fix some spalling bricks into patching an area on the south wall. I simply assumed the skills needed were one and the same. He was a bit disinclined, a cue I should have taken, but then agreed. Once his patching was done, I completely got the hesitation. In contrast to the neat bands of mortar he placed precisely between the courses of the bricks, his approach to stone involved smearing mortar across the joints. I’m unsure why irregularity should cause that response in a bricklayer, but the results were unfortunate for the look of the foundation. Later, I spent not a few hours chipping away the worst of the smeared cement to make the joints recede and restore something like the original look.


Mortar smeared across the seams obscures the look of the stone wall

A section of rubblestone foundation wall whose base has been rebuilt and repointed


While watching the bricklayer go at this work, I realized how ungainly his attempts to get the mortar into these wandering seams actually were. Using a pointed mason’s trowel for the carry and a smaller one to push mortar into seams just didn’t cut it. A pointed trowel may be a great tool for dressing a brick before placing it, but for infilling irregular seams in a rubble stone wall it clearly wasn’t working. The outcome argued against continuing down this path. The thought dawned that I myself needed to learn how this type of work should be done, so further damage to the look of the building was avoided. I don’t know why I opted to get personally involved rather than just finding a skilled stone mason, yet it was but a small step from there towards working directly with stone. 


Continuing repair: base of a foundation pier needs attention



A stone base under a house creates a distinctive impression, gluing the building firmly to its site in a specific way. If the rock used is taken from the site itself and the building sits on bedrock, the house feels like it's one with the landscape. But let that look become marred by entombing the walls in concrete and the stone is demoted to an indistinct element in a matrix, causing the original aesthetics to recede. Taken far enough, it disappears entirely. You may as well have a full concrete foundation as have rocks masked by mortar. I thought it important not to go any further down that path.


Vertical seams with mortar slathered across them: messy work


So that's when I naievely started on what is now twenty-five years of working with stone and mortar to repair and make things. I wasn't DIY by nature, had no skill at all when I began, but was intrigued by the medium and resolved about the importance of maintaining the heritage asset. And I was a gardener, so had some experience making loose rockery walls for beds, and had an inclination to pile rocks together as a result. I decided to begin by tackling the most visible breach first, upping the ante considerably. It appeared at the centre of a low wall between two tall battered piers supporting the house’s most prominent feature – an elegant entry verandah that one walks by on route to the front door. It appeared that a few weaker chunks of rock had popped apart, causing a crack to appear.  


The scene of my first job: fixing a serious breach in the low wall between the two stone piers

I hadn’t a clue how to go about making a repair, so I began by observing some of the masonry work in progress around the region, which was mostly of the low stone wall type. Around Victoria rock is always breaking through the biosphere, dotting the landscape with  outcrops and large hills not fully covered with vegetation. Bedrock breaking through the landscape defines dramatic contours, and loose rock on the surface seems to prompt a lot of boundary marking with stone walls. And because the material is local and often not much worked before using, the results can feel natural and fit for their surroundings. 


A small knob of glaciated bedrock in a school yard protruding through the organic layer

Rocky outcrops define a landscape that rises and falls, dotted with oak, fir and arbutus groves


Victoria regional character: rocky outcrops, Gary oaks and rustic boundary walls



The operations I observed and the masons I chatted with all used  mortar made from scratch, combining sand, cement and water in mechanical mixers to produce large batches at a time. My first problem was that none of this apparatus would fit in at my site, which offered no place to store and mix sand and cement that would not have been an eyesore and in the way. Nor were industrial quantities of mortar actually needed for the relatively small and picky repair work I’d be attempting. How to access mortar in small quantities was an initial obstacle to getting started.


Bodged work stands out, covers faults, doesn't last
 

Things stalled there for a while, until the puzzle of making mortar solved itself with the discovery that it came premixed in 25-kilo bags – not exactly a blinding insight, but until you know of the possibility, it doesn't exist. I learned about it by chance, in a buddy’s back garden, when he enthusiastically shared his rather exuberant approach to building a low retaining wall. I watched fascinated as he whipped up a small batch of mortar in a plastic pail (‘just add water and stir’), then proceeded to use another one of those pointed trowels to rather awkwardly place it. It was a eureka-moment - here was a way to make mortar that was manageable for repairs.


If sourcing mortar is essential, it’s also necessary to have tools suited to the work of mixing it up and placing it without undue mess. There things remained murky a while longer. To repair an existing wall, you need a way of transferring small quantities of mortar to niches of varying size. This is quite picky work. And moist mortar is prone to sliding on metal, a bit unpredictably. And you need to place it with enough precision, in awkward spaces and odd angles, to avoid marring the face of your stones. Otherwise, you risk the look of entombment, which is pointless and inartistic. 



Successive bodges mar this ill-fated stone wall, which even retrofitted drains aren't saving
Stone retreating behind slathered mortar, a once-artful artifact now imprisoned in concrete


As I began preparing the breach for repair, I anxiously watched the opening enlarge beyond the apparent problem and the scale of the job increase in tandem. I'd improvised a partial solution to the transfer problem by selecting a compact drywall knife in preference to a trowel. Initially I chose it just to mix up the mortar in a pail – its continuing utility evolved naturally from there. A compact blade offers a horizontal platform from which small quantities of mortar can be eased into seams.  I am still using Quebec-made Richard knives to this day, both for repair and for new construction.



Top, pointed mason's trowel, below, Richard knife, a practical tool for repairing joints

Yet another tool was needed in order to transfer the mortar from the knife to the seam and to work it into place. One day, watching a city worker setting stones in a piece of sidewalk art, I noticed he was using a table knife to fill and dress the openings. He allowed that he’d ‘borrowed’ it many years back from his wife, but hadn't ever returned it. He used its narrow blade deftly to work the outside of the seam, so the mortar stayed within the lines and even had a bit of a finished look to it. 


Intrigued, I borrowed an older knife from my own kitchen, a strong but thin steel blade with a bit of ‘give’ to it. The combination of firmness and give allows a surface tension that’s useful in working mortar into crevices. It mimics the design of a mason’s pointing tool, which has a similar spring or tension to it. I soon realized I would need to get mortar into spaces too tight for the width of the knife's blade, so I also acquired several of the pointing tools used by masons (I'm still mystified why the mason I originally hired opted not to use pointing tools to push the mortar into the seams!).


Basic tools: the original kitchen knife (right), drywall knife, and four tuck pointers


While I was still stymied by the challenge of making mortar, I bravely allowed myself to start the job by removing the defective pieces. This phase of repair typically establishes the real scope of a project, as loose material behind the breach comes to light. Here it revealed the presence of a brick pier, obviously meant to support the verandah floor in the vertical plane but now tilting alarmingly due to brick disintegrating where it contacted wet ground. Evidently it was the movement of the pier that had caused the wall to crack and come apart. This new problem caused me some anxiety about proceeding at my skill level, but I decided it was better to know about it and attempt a repair than to neglect it and soon cause a bigger problem. I was also realizing I'd have to replace some rocks that had actually broken apart, and that compatible materials needed to be found.

1989: the leaning brick pier, replacement stone in front of opening, and pointing tools


Getting to the point of mortaring anything took a very long time, but a logic for placement emerged once I located some suitable stone and dry-fitted it as best I could. A skilled stone mason would be able to visualize an outcome without needing to mock it up, but as a beginner I needed to see in advance as best I could. The trick lies in finding material that mates well with what is already in place, so the patch doesn't call attention to itself. Here the challenge was to fill up the opening as much as possible with a single piece while maintaining a vertical alignment consistent with the rest of the wall. And then to place it and seal it as though it had always been there, leaving no blatant traces of repair. It complicated matters that in this location the bedrock dipped somewhat.


There was a lot of loose rock lying about the place, but nothing that felt right for the opening I was dealing with. So I began scouring highway cuts and old excavations looking for local materials, which back then could more readily be found. Finding useable material is part of every job, and compatibility is always an issue when working on an existing structure and striving for seamless repair. Nothing shouts 'bodge' like stark contrasts in materials – unless it’s sloppily applied mortar. My first structure was well-weathered at seventy-five years of age, made of local stone of various colours and textures – the opposite of ‘green’ stone of uniform colour. Mating new and old was a challenge that had to be met with careful selection. 


Above and below: many years on the repair is still holding, doesn't stand out as incongruous




Eventually I found what I thought was a suitable piece for the biggest opening, then assembled a supporting cast of smaller pieces to fill gaps to neighbouring stones as well as other crannies in the wall. It took a painfully long time to complete this small project, a result of proceeding slowly with awkward hands learning to slide mortar carefully into place (a moving target that) and then smooth it to a uniform face. A comparable awkwardness might be the one a boy experiences when first trying to guide a razor over the contours of the face. The kitchen knife however quickly proved invaluable, and in time a rudimentary process for transferring mortar evolved. The trick was keeping it where wanted despite gravity-fueled tendencies to travel where it wasn't. I kept a wet sponge and toothbrush handy for cleaning sloppage from the stones. Vertical seams are bedeviling, even to this day. A special tool for vertical placement is an obvious gap in the repairer's tool bag.


A massive stone pier that also turned out to need repair


When finally completed, this first project gave me a sense of satisfaction far beyond the modest scope of the work. I felt I’d opened a door to the world of stone building and won some knowledge through the execution of the work, despite offending many rules I was then totally unaware of. And while my hands would be busy with restorative projects indefinitely, completing just one prompted me to wonder what it would be like to make something from scratch. That experience lay close to hand: while passing many an hour staring at the repair's slow progress, I'd also noticed that the massive uprights supporting the verandah roof were beginning to come unstuck at the base. While one of these could be repaired as was, my intuitive feeling was that the other needed a foot, or plinth, added to truly secure it. It appeared that there was a brick support at the heart of the stone pier, and that as with the wall, the bricks were spalling where the base sat on moist rock.


Looking back on it, this was a very big leap for a newbie. The implications were potentially large, because I was about to modify an original design that was substantially intact. Indeed, aesthetically and from a distance, it wasn't at all evident that anything needed to be done. But looked at closely and carefully, it was obvious that it did or else risk the integrity of the original down the road. And I knew I wasn't capable of rebuilding that pier to its current standard. So I decided I would proceed by laying out the design for a base completely before placing any stone permanently – and only go ahead when I was satisfied it would be aesthetically compatible. This was a brave step along the problem-finding/problem-solving continuum.
 
The goal was to make the plinth feel like it was always there



This second job led to more searching for appropriate materials that fit the existing composition. It was only a minor amount of new construction, but visually it had to be right and so it too advanced at a glacial pace. As compatibility was imperative, I studied the shape of the existing construction and the way the rocks had been put together for a subtly rustic effect. Eventually, by endless playing around, I got what I thought was a goodish look, meaning one that wouldn't stand out as incongruous or arbitrary. And with my evolving skill in placing mortar, the job moved slowly but steadily forward in execution (new construction is far easier than repair for managing the mortar). When I look back on this small yet prominent project, I’m amazed I tackled it with so little experience. In effect, this repair is what launched me on the path of new building with stone. Looking at it twenty five years on, I take satisfaction from the fact that the eye doesn't notice anything that's amiss, that what was an original artistic ensemble before my hand was on it, remains one after. 


Powder lichen and other elements of weathering help the new base feel like its part of the whole

Down the line there were many such repairs (still are) plus a whole lot of dry stacked garden walls between me and the next bit of new stone construction. But my choice to tackle repair myself had launched me on a path that continues to elaborate itself 25 years on. I haven't become a stone mason by any means and it's probably too late to acquire true journeyman's skills in any systematic way, but my skillset has developed in the ways needed to do the jobs of repair and addition required in my own milieu. And using those skills has become an increasingly expressive act that continues to hold my imagination. More on that in future posts.




Dedication: this piece is affectionately dedicated to my too-early-departed friend Dennis McGann, a hugely talented designer, communicator, and artist who, among many important things, inadvertently turned me on to bagged mortar. Dennis respected and cultivated craft in all his doings and equality in all his dealings with people. He was a fine person, sorely missed.