Experimental Homestead

Adventures in Chinese slate



Adventures in Chinese slate:  In which I find myself intimately engaged with the harbor freight of slate. :(

When I was preparing to move here I started trying to collect building materials in earnest.  I was looking around for roofing tiles and ran across a pile of roofing slate for sale for $400.00  I was intrigued and called around about slate roofing prices to see if it was a good deal.  It sure seemed like a super good deal.  The guy said the slate was originally from China, was left over from a large job, and had to be gone by the next day.  Our land partner at the time went and picked it up in his ford pickup with a rented flatbed trailer.  The trailer brakes weren’t working on the trailer and he had to navigate rush hour bay area traffic with 8000 pounds of slate.  When I talked to him on his way back to ask him how it was going he said… “well, you couldn’t drive a pin up my ass with a sledgehammer right now!”.  Lesson number one:  slate is heavy and trailer brakes were invented for a reason.  Later, the truck overheated on the way up the hill with half that amount of slate.

When the slate was unloaded we sorted out all the cracked and broken pieces.  I got a copy of the slate roof bible which has all the necessary tables for calculating coverage and I figured I had almost 10 squares (a square is 100 square feet of coverage when all the tiles are overlapped properly).  We framed up a building a couple years later with plans to put the slates on it.   We milled the wood and built the structure to support a slate roof with full 2×8 rafters and a 1 inch deck (probably overbuilt).

I did all the necessary research and planning bought some slaters brackets, a slaters hammer, and a slate cutter.  I had to move all the slate again to get it to the building site and in doing so (now knowing slightly more about slate and getting down to the nitty gritty) I tested every slate by ringing it which means I tapped it to see if it sounded dull (cracked) or bright.  I guess in being shipped from China- then moved to the distributor— then to the job site—– then to where it was stored afterward——- then to our friends garage——— and then here———–, a few slates broke.  I re-calculated and found that my original estimate was off anyway and that with the broken slates out of the picture I was in the neighborhood of 5.5 squares and I need 6.66 squares for my roof!  After going through the stages of loss or whatever its called… anger, denial, grief etc…. I reached a state of annoyed acceptance.  Oh well, live and learn.  I would just have to put this slate on a smaller building.  So I moved it again.  Lesson two:  Slate is still heavy and an accurate estimate of coverage and quality would be in order.  (and its hard to pull your hair out when you have dreadlocks ((is that good?)) )

It was time to move the slate to the smaller building and whip that out!  In moving the slate again, more broken pieces showed up.  Moving was done pretty careful this time, so many of these must have been missed in the last move or were just really weak to start with.  No matter, the new roof was under 250 sq ft and I had 5.5 squares so I could afford to be picky.  I began planning my roof.

I decide to go with a blue belly lizard theme because the lizards hang out around that building a lot and are kind of  a mascot around here.  I took some close ups of lizards and tried to draw up a pattern that would be something like a stylized lizard scale pattern.  It sort of worked in that regard and whether it conjures up that image in people, it certainly looks awesome.  Each slate had to be cut to pretty exact dimensions because the pattern relies on the row above aligning exactly with the one below.  This was a lot of work.  Lesson Three: It takes a long time to cut slates into exact dimensions and fancy shapes. (especially when they are a varying quality and thickness.

Lizard roof ridgeline. The best and thinnest uniform slates were saved aside for slating the hips.

In cutting the slates I noticed that many were softer with a chalky feel and a hazy looking surface where they were exposed to the sun.  I know what this means from the book learning I have engaged in.  These are crappy slates.  The quality of the batch is mixed.  Some are hard and have a hard crunchy sound when they are cut, but most, and especially the thicker ones, are not so crunchy.  They will probably absorb a lot of water and fall apart all too soon under the action of air, water, varying temperatures and sun.  Who knows how long it will take before the slates start falling to pieces and actually causing leaks.. 20 years, 30, 40, 50?  I don’t know, but I’m pretty sure this is not going to be a 100 year roof.  Too bad because it was a lot of work.  It is claimed that Chinese slate is often of poor or at least mixed quality.  This slate seems to be of mixed quality.  Lesson number four:  Chinese slate, as is often stated, can be of mixed or poor quality.

I started the roof. There was a learning curve for sure and the first side (the least visible one) has some bumps and warts, but nothing too major.  According to the slate roof bible (which has been almost my sole guide besides the slate roofing forum), the nail holes should be just above the last row of slates.  But on these slates they are not.  The holes in these slates are near the top so I had to punch two new holes in every slate.  I punched them on the roof with the slating hammer.  I got pretty good at it, but found that thick soft slates punch very well necessitating that I drill and counter sink many of the thicker ones which takes much longer than punching.  Even if the holes had been placed in the right place, they were also drilled and not punched and the drilled holes are not counter sunk.  When a slate is punched it pops out a cone on the top of the slate for the nail head to lay in so that each nail head is below the slate’s surface and will not rub a hole in the slate above it.  If slates are drilled, they must be counter sunk as well to achieve this effect.  Lesson number five:  My Chinese slate was drilled instead of punched which would be Ok if it was counter sunk as well, but its not.  Further, the holes are in the wrong place… more about the holes presently.  I suspect that much of this slate would not punch well at all, and it is no doubt faster to drill a stack of slates all at once than to punch them one at a time.

Another thing I noticed is that the slates are widely varying thicknesses from extremes of 1/2 inch down to 1/8 inch.  Varying thickness presents a problem in laying the slates because if a thin slate is laid next to a thick slate then the slate overlapping the two of those may have gaps beneath it.  This is not an insurmountable problem, but it takes considerable time to pick and choose the slates.  I adopted a strategy of using thickest slates in the center of the roof and tapering down in thickness toward the edges… not a deal killer, but time consuming.  Lesson 6: Varying thickness slates take longer to lay, (and may eventually present a problem when laying ridges and hips).

…Dang, this slate is drilled on the thick end… so is this one… that ones Ok, but not this one… cull… cull…. cull….

Slates are often thicker at one end than the other. When the workman at the quarry picks it up to punch it, it should be punched on the thinner end.  If the holes are at the thick end, then the slate doesn’t lay on the roof well.  Actually, what is more of an issue is random differences in thickness aka lumps and swells.  This slate varies from very uneven surfaces to very flat.  On the very lumpy surfaced slates, the bumps can really get in the way and in the event that they occur at one end of the slate, that should be the end which is exposed on the roof.  If the bump is left at the top of the slate, the slate above it has to lay over the bump and it will not lay flat.  It was clear that I would have to use a lot of substandard slates to get through this job, so out comes the angle grinder.  With a diamond cut off wheel on a four inch grinder I can pretty easily grind off irregularities on the roof as I work, but it takes time.  Lessons 7 and 8: If the holes are not in the right place, plan on extra time punching or drilling and countersinking…. and slates that are very irregular in cross section are difficult to lay and you will end up with a roof that has large gaps between the slates or you will spend extra time choosing and/or reshaping them to compensate.

Ok, this slate is concave… cull… that one is Ok… this one is convex… cull…. cull and this one has a propeller twist. A little concavity a little convexity, no problem really, but I culled quite a few that were too drastically convex, concave or propellered to use.  Is that a lesson?  I guess so.

Recently I picked up some Vermont slate from Camara slate company.  This is also overage from a large job.  By comparison to the Chinese slates I’ve been using it is really dreamy.  The holes are in the right place, the slates are flat, they are uniform, they have an acceptable thickness range, they have on the whole very uniform surfaces, Where there are irregularities in thickness, they are punched on the correct end. They feel hard and in spite of shipping and moving a few times there are remarkably few broken slates.  This is good slate.  Contrast it with the Chinese slate I am using.  I’m sure that Chinese slate is much cheaper, but If you have 50% culls and breakage and it doesn’t last as long then how good is your deal on cheap slate?  And, maybe more importantly, there is much added labor in laying poor slate and yet more again in the sorting and culling of it and I’m here to tell you that is a thing which is not to be underestimated whomever does the work.  I now have a large pile of reject slates.  In spite of having about twice as much as I needed, I’m just going to squeek by.  Fortunately, many if not most of the unbroken culls will still be useful for a very rough shed roof or something like that.  I can use the broken ones somehow.  Nothing will be really wasted ultimately even if it ends up being gravel.  But then I wouldn’t knowingly import gravel and garden paving from half way across the world.  Still if I had been counting on using it all for a nice roof I’d be sorely disappointed…. oh, wait, I was.

Beautiful, hard, uniform Vermont slate :P

Now its possible, if not likely, that what I got was largely the culls from slates that were bought for a large roofing job.  Even so, there is no good reason (from an ethical buisness standpoint) for many of these slates to have been finished or shipped out in the first place.

Let me just get out my soap box.  What I ended up with in my ignorance was the harbor freight of slate.  Although several times a year someone tries to convince me to go to harbor freight to buy this or that really cheap tool, I don’t shop there.  I don’t shop there for reasons basic to my world view and philosophy.  There are reasons that products made in such places are cheap.  One reason is that they are on the average of very poor quality in workmanship if not materials as well. The sad truth though is that there is a market out there that will purchase substandard products over and over simply replacing them with more substandard products when they fail and still thinking that they got a great deal.  Occasionally it may be a good deal and the quality of Chinese goods is not bad all the way across the board, but that is of course not the phenomenon I’m speaking to here and if it seems too cheap to be good, it probably isn’t good.  I can just imagine Homer Simpson buying the same tool from harbor freight over and over again saying DOH! when it breaks the first time he tries to use it and smiling and drooling while he hands the cashier more money for the next one.  Ahhh, Homer Simpson america’s ugly underbelly (or is it overbelly?).  Homer is not going to think past low prices.  What for instance, about resources?  The resources that go into these cheap goods are still valuable resources.  Energy, raw materials and human time and energy are the things that all goods are made of, even cheap ones.  Its just that in the case of inferior goods these resources are largely wasted with a short useful time between production and landfill.  Shoddy goods waste way more resources.

The other reason that these goods are cheap is that some under privileged person has to produce them.  Imagine getting up in the morning and deciding you’ll go get a job at the slate quarry where each day you’ll be greeted by hard labor, producing goods you could never afford and that are still after that consideration possibly not worth having at all.  Yay, lets quarry a bunch of slate by hand today so that a large percentage can be culled and end up in a fucking dumpster somewhere in america and the rest to follow when it begins to fail!  What?  Punch the holes?  and in the right place?  Why bother?  americans will buy them anyway.  Oh look dear, look how cheap the slate is.  Or maybe you’d prefer to choose a job making throw away plastic toys or electronics?  These jobs are by and large performed by people who are forced into them by economic and political conditions beyond their control, if not worse.  They are real people with hopes and dreams and aspirations grinding their lives away in some factory or quarry to make goods that mostly end up in the hands of people in wealthier countries who don’t actually need them at all, or of which they should have available (and should choose) a better example.  If, like me, you try to avoid buying shoddy goods from foreign lands you might have noticed that it is increasingly difficult to find goods that are not made in China.  I was given a gift certificate to Ukiah Natural Foods Co-op and I could scarcely find anything interesting to buy in the kitchen and “durable” goods section that was not made in China.  This condition exists because people are willing to buy these goods and clearly this extends to liberal health food types.  I, like many people, have been lured into this trap headlong before.  And too often I still find myself in need of some thing that I can’t get or can’t afford the well made and preferably domestic version of.  Or how about even having time and energy to ferret one out?… if there even is one made anymore!

In the big picture though, which is what moving toward a sustainable lifestyle is about, there is no place for this economic model.  It is a model that has no overarching merit.  It is a model devoid of consideration for others.  It is a model that overlooks the finiteness of our planet and its resources.  It is a model that buries your children’s future in toxic garbage and failing life systems.  It is just gross and though I’m a die hard relativist, it is “wrong” from any view that would claim to embrace the ideas of fairness to others and respect for everything that provides us with life and beauty.  So don’t show me the cheap shop press you got to press your apples or your new chop saw that was 1/4 the price of a name brand.  Maybe we’ll all be better off if you accidentally make cider out of your head or door trim from your arm or have a heart attack while dragging your bargain off to the dump when it breaks.

When we purchase goods we are not just buying the product itself.  We are also buying the consequences of its production and disposal… its origins, its truths, its disposal. We need a major paradigm shift in consumption where the ripple effects of our purchases are considered more than the usual “can I afford it and do I want it” that guides the gigantic majority of purchases.  What if we were to stop in the store and contemplate for a moment the beginnings and inevitable end of everything we buy?  That picture is grim enough with out the low quality throw away goods type of consumerism that we seem to be sliding ever further into.

In some ways my second hand Chinese slate was not even a bargain at what must have been way less than retail.  When I looked into it, I was surprised to find that quality slate for reasonable sized buildings is actually not so unaffordable when compared to quality standing ridge metal roofing.  Yes, it is more, but there is a way of thinking in which it is the better choice.  Roofing slate is not produced on the west coast as far as I know, so it has to be shipped from the east (although there may be suitable slate here that just hasn’t been exploited).  But where is the metal in your standing ridge roofing from?  it had to be quarried like slate, only probably much more material of ore and tailings per unit of finished roofing than slate (I’m guessing).  Then the ore is transported and then processed using quantities of lime and coal which also have to be quarried and transported.  Slate, for contrast, is processed into finished units on site with some simple machines and hand work.  The raw steel for roofing is probably shipped somewhere to be made into roofing, the roofing is painted etc which entails more resource use… and then the finished product still has to be shipped to the point of use.  I wouldn’t know where to start to do the carbon foot print on it all (not that CF is the only consideration), but slate is looking pretty good.  It will also last a very long time 100 years?  200?  yes, really.  And its fire proof, totally repairable, reusable and gorgeous.  I won’t even put the short lived kitty litter covered composite roofing most people use into this equation.  “Can’t” afford slate?  Really?  What many people mean when they say they can’t afford something is that they can’t afford it while maintaining this or that standard of lifestyle.  I live in a single income family which has only recently started to generate funds just above the poverty level.  On top of that we are buying and developing property and we can “afford” it. This has more to do with our values and priorities than with our income.  It also has to do with the fact that we put in a lot of sweat equity.  I know that isn’t always the case and many people just won’t be able to afford slate.  But don’t be so attached to that bargain or think you can’t afford to invest in quality until you examine where the money you could spend on a modest slate roof actually goes instead.  And if the building is too big, maybe you should consider a smaller one.  More affordable to build, less energy to heat, less resources used, less labor to clean and maintain and the roof would be much cheaper.  The medium is the message and slate is a medium that speaks values that, at least to my way of thinking, are good ones.

The ubiquitous bluebelly

As it stands while I write this I have three sides of the lizard roof finished.  It looks awesome and has been a great learning experience.  I hope to finish the lizard roof soon (if it ever stops raining) and start on the Vermont slate cottage roof this summer.  I hope my little story is of use to someone out there working, or planning to work with, slate.  After my experience so far with the substandard material I’ve been working with, I’m so excited to use some quality slate!  I hope to update this post with finished pictures of the lizard roof when I have them.  I also may end up blogging more extensively about the lizard roof design and experience at some point.

June 28, 2011 - Posted by | Infrastructure | , , , , , , , ,


  1. I absolutely agree. I have basically stopped shopping at all, thinking about the life cycle of the products on sale make me so sick I don’t even by stuff I actually kind off need anymore. If it were me I wouldn’t touch the slate stone roof until I had an income stream and a future usage plan stretching into 4 generations of kids and grandkids to justify the cost of that roof. Living roofs, birch bark roofs, thatch or straw roof can be locally sourced in most climates I believe, and transported and assembled with a bare minimum of hand powered tools if necessary. Although a pack animal would help I guess. These natural roofs, totally DIY projects can last anything from 20 to 60 years, more than enough for me to do it once to learn myself, and then once again to teach the offspring. Still, slate is lovely looking and a superb choice compared to most other manufactured materials. I do hope the roof is still there for your great-grandkids to marvel at! Thanks again for a lovely blog and a lovely post. Keep them coming!

    Comment by tokyobling | September 10, 2012 | Reply

  2. Right On Dude. You make some major points here about cheap short-lived stuff costing as much in raw materials (energy, natural resources, water, etc) as expensive well made stuff. It never occurred to me before but you are bang on brother.

    Comment by Jon Cloud | February 27, 2013 | Reply

  3. great article

    Comment by James | May 23, 2013 | Reply

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: