Sunday, September 17, 2023

Connecting With Stone


A rough stone base links this 1913 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 closely examining all the parts, then gradually awoke to the realities of the work needed in order to stabilize and repair the building.

As I settled into my new home, I began noticing among other things that its sturdy stone base in fact sported 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 mortar. The materials comprising it were ordinary, mostly collected on site, and randomly set without conscious patterning or coursing. A lot of different shapes and sizes of stone had gone into that foundation, with a crazy-quilt of seams as a result. 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 tremors, 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 and easily crack rock walls

A section of wall broken by expanding roots, needing attention


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 more 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 chimney bricks into patching an area on the south wall. I simply assumed the skills required 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 his hesitation. In contrast to the neat bands of mortar he placed so precisely between the courses of the bricks, his approach to stone involved smearing mortar across the joints. I’m unsure why irregularity of form should cause that response in a bricklayer, but the results were unfortunate for the look of the foundation. Later, I spent a few hours chipping away the worst of the smeared cement, to make the joints recede in emphasis and restore something like the original look.
Mortar smeared across the seams obscures the look of a stone wall
A section of rubble stone foundation wall whose base has been rebuilt

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 the seams simply 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 I could avoid further damage to the look of the building. 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 to working directly with stone. 
Ongoing repair: buttress needing attention

A stone base under a house creates a distinctive impression, gluing the building firmly to its site in a particular way. If the rock used is taken from the site itself and the building sits on bedrock, the house feels at-one with the landscape. But let that look become marred by walls entombed in concrete and the stone is thereby demoted to an indistinct element in a matrix, causing the original aesthetic 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.
Seams slathered in mortar for a messy outcome

So that's when I naievely began what is now twenty-five years of working with stone and mortar to repair and make things. I wasn't inclined to DIY by nature, had no skill at all when I began, but was intrigued by the medium and resolved about its importance in maintaining the heritage asset. And I was a gardener, so had some limited experience making loose rockery walls to retain beds, with 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.  

My first job site: a serious breach in the low wall between the 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. Here in Victoria rock is always breaking through the landscape, dotting it with outcrops and larger 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 this material is local and often not much worked before using, the results often feel natural and fit for their surroundings.

A small knob of glaciated bedrock protruding through the ground

Rocky outcrops define a landscape with oaks, firs and arbutus groves

Regional character: rock outcrops, Garry Oaks, 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 had 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, doesn't last

Things stalled there for a while, until the puzzle of making mortar solved itself with the discovery that it came pre-mixed in 25-kilo bags – not exactly a blinding insight, but until you know of the possibility, it doesn't exist. I learned about it purely 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 bagged 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 stayed 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 at 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 stone wall, which even drains aren't saving

Stone retreating behind mortar, 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.
Impractical mason's trowel above, useful Richard knife below
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 enables 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 mortar into the seams!).
Basic tools: kitchen knife (right), Richard knife, 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.

Securing the brick pier before fixing the wall

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.
Candidate replacement stone being positioned for fit

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. 
Many years later the repair doesn't stand out unduly

Replacement stone is broadly compatible with the original rocks

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 also 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.
Massive stone pier also needing base 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 actually lay close to hand: while passing many an hour staring at my repair's slow progress, I'd also noticed that the massive uprights supporting the verandah roof were beginning to come unglued 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 column 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.
Making the plinth to feel 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 didn'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 amiss, that what was an original artistic ensemble before my hand was on it, remains one after.
Weathering elements like powder lichen help the plinth blend in

Down the line there were many such repairs (and still are) plus a whole lot of stacked garden walls between me and the next bit of new mortared 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 certainly too late to acquire true journeyman's skills in any systematic way, but my skills have 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. 
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 who is sorely missed.

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