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Dale's Cob Bench Restoration Project – Remaking to Survive Wet Climate  RSS feed

 
Dale Hodgins
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Location: Victoria British Columbia-Canada
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Dale's Cob Bench Restoration Project – Remaking to Survive Wet Climate

I hadn't taken much notice of this bench in several years, since it's in a spot where I often drive by but seldom walk. I thought it was covered in ferro cement or stucco. I walked by it yesterday and immediately realized that it was cob and that without serious intervention it would be a mud pile within a couple of years.

It is only about 6 years old, but has seen no maintenance at all. Many of the features were added without regard to drainage. In this climate unprotected cob can go bad quickly. Poor design exacerbates cob's vulnerability. The better surfaces that aren't eroded as badly are rather hard and whitish, so I think it may have had some whitewash in the beginning. It is currently absolutely saturated. The top of the back rest is flat and water that soaks in there has sprung out near the base.

I plan to fix this mess as soon as the weather breaks in the spring. For now, it is to be protected from rain with a tarp.

These pictures show a broad view of the extent of the damage.

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Dale Hodgins
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Posts: 6704
Location: Victoria British Columbia-Canada
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The bench belongs to the area's largest volunteer organization and I've been promised lots of help. I'm volunteering my time. The organization is buying the lime putty materials and pigments, so it won't cost me anything. This should leave me with enough money to get my head examined.

The worst area is the top of the back rest on the windward side. The last photo shows a weep hole that drains water that was absorbed elsewhere.

Before we get to weather coating it, the badly washed out areas will be excavated and re moulded to shapes that run water. The back of the head rest will be first carved off a bit so that it slopes toward the rear and then it will be built up at the front until about a 30 degree slope is achieved. This will reduce the splashing which is eroding the arm rests. I plan to remove some of the pebble and glass embellishments. Someone put in many hours installing little glass tiles which have mostly flaked off of the back rest. Rather than try to restore detail, most embedded items will be scraped off and the holes filled.
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In order for the bench to still look quite artistic, we're going to have someone paint it with coloured lime paints that are compatible with the weather coating. Their work will be regularly covered over(every few years) whenever maintenance is required. So the bench will be a temporary canvas where volunteers can display their artistry.

The activity director is confident that she will have no problem finding willing participants. A design contest will determine which individual or group does the next set of murals. No carving into the cob will be permitted except with my approval and the existing sea creatures must remain and be well integrated into future designs. I could see a sailboat, kelp beds, sunset, killer whale, seals, rocks and sea bird murals blending well with what already exists. All of this lime paint will serve to protect the bench. From time to time, I'll pop by and use a little of the base colour to nip maintenance issues in the bud. Once a set of murals has seen better days it will all be whitewashed over unless it is very popular and the artists are willing to go over it again. Otherwise a fresh canvas will await another set of artists.

When the bench was originally done, I'm told that the original artists didn't want anyone making changes. They and everyone else failed to look after it, so now I will decide how all of their hard work looks into the future. The hands off approach failed miserably. I think this new approach could preserve the bench for 20 years or more --- if it survives this winter.

I've never restored cob before and welcome technical advice on how to patch it up.

Thank you: Dale Hodgins


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Dale Hodgins
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Location: Victoria British Columbia-Canada
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I met one of the original builders on the 23rd. She lives on a property that contains about 30 cob structures ranging from 4 well built and maintained houses to garden buildings that were built too close to the dirt with inadequate roof overhang. Most are repairable with a few tweaks while a few are pretty far gone and some would require a total redesign of the roof to attain long term durability

. She's putting me in touch with the person who did the plaster. The bench was built as a workshop project, so exists not so much because a bench was needed but because workshops are a profitable for those who conduct them.
 
Dale Hodgins
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ernie and erica have given me plenty of good advice on how to harden the surface with a very thin lime wash which sinks in deeply. This gives future coats good bite so that they don't flake off. Ernie said that expanded metal lath works better than a wire brush for abrading loose areas. We all seemed to agree on what caused the problems, so I won't recount it all again.

The photos below show a perfectly preserved bench that is built right and well maintained. The surface is coated with linseed oil and bee's wax. The cedar bench drains to the front and back. The whole structure has good solar exposure and good airflow. It's a job to be proud of.

I'm going to see if the ladies who built it will help out with the other project. I definitely want to meet the sculptor. I'll be offering her and her family some bus trips in exchange for some nice sculptural elements for my own buildings. I'm thinking the forge could use a mural of Medieval metal working and the potters kiln could use ... and the barn....
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Dale Hodgins
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It's been over a month since plans were made to fix the bench. Yesterday, I spoke with a lady who was heavily involved with both projects and who donated many hours of labour when promised volunteer labour was insufficient to finish the eroded one. It turns out that both benches were community projects using mostly volunteer labour and not profit driven workshops. So the disparity between these two projects is mostly because of what has happened since their creation. Contrary to what I had been told, there was never a plan for the builders to maintain the bench. That job was left to the owners and the agency that originally funded construction. This is why I like private ownership and responsibility. If the bench were mine, I would have built a roof over it --- case closed. In order to get a roof over this one, we'd need a committee and the city to agree upon it, followed by a fund raiser. Here we have an example of the tragedy of the commons and how bureaucracy can complicate any task. Now, close your eyes and imagine me ranting on for an hour and a half about how each man is an island, government be damned ... bla bla bla ....

The poorly maintained bench was largely forgotten about by the agency who funded it. This is consistent with what I've witnessed with the garden shed project only a block away, built by the same group. The nicely maintained bench is still maintained by the original builders. It's in their neighbourhood and the community centre pays for supplies. After it became clear that the eroded bench was not valued to the same degree in the neighbourhood where it resides and that the agency who funded it had no interest in maintaining it, the builders, having done their part, left it to the owners.

I suppose I'll find out soon, whether or not volunteers can be raised. Ernie prescribed several coats of thin lime wash to stiffen up the weakened cob. Lime is easier to spread if prepared months in advance. I will get the owners to buy all materials soon and get them to post notices for volunteers with my phone number as the contact, so I can be sure that people do in fact want to get involved. The promised rain cover has not materialized, so I'm cautiously optimistic.

The moral of the story. Cob requires a roof if it is to survive in a rainy climate. I remember reading that one county in southern England has over 40,000 cob homes, most of them over 200 years old. A Google search, failed to turn up cob benches exposed to the elements in that area.
 
allen lumley
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Dale : Yes ! I am sure that it only feels like I have been holding my breath, 'cause I know I can't hold it that long - I had a thought that as a public service, maintaining
these Cob Creations would be a great teaching tool on so many levels

So your rules would be close to :

- If its worth building its worth maintaining

- If its worth maintaining its worth having a roof w/ wide eaves, and should up off of the ground


- If they won't maintain it - its poorly sited ?


For the Good of the Crafts ! be safe, keep warm ! Think like fire, flow like gas ! PYRO - Magical Big AL !
 
Dale Hodgins
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I JUST LED A SUCCESSFUL COB WORKSHOP ! Other than the various test mixes that I've made, this was my first project using cob. It all went like clockwork. I have committed to memory all of the required skills based on YouTube videos and some advice from Ernie and Erica. Four helpers showed up right on time and there was total cooperation.

I put in an hour last night, gathering clay and sand and l brought more tools than were needed. Another 4 hours were spent chipping away soft bits and preparing clay. The hedge was cleared to give rear access. The crew arrived at 9am and after 5 minutes of introductions and orientation, we went at it. The only surprise was the amount of misting required to keep the material workable. The bench absorbs water readily. We went with with small batches of about 35 lb.

Most of the sculpture bit is done and we are done for the afternoon. At 7pm we'll put on the final smooth coat. It will have all week to dry and crack.the helpers know that it will crack but I'm sure that some will be shocked at just how much. The cracks will be filled a couple times and then several lime coats will go on.

Most pictures are on the camera but these were on the phone.

The last photo shows a thin slab of decorations that came loose with a light tap. Most embellishments were removed.
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Dale Hodgins
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It's a dry, windy day so the tarp is in place to prevent evaporation. The ground around the bench will be soaked all week and the surface misted whenever cracks are filled. I hope to finish next weekend and turn it over to artists who will tint the lime wash different colors for the sculpted salmon and starfish. Other sea life will be painted on the empty areas. I've never painted a killer whale but I may use that big open area between the salmon for my first go at it (:
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Dale Hodgins
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It's nearly dark and done for now. The thick areas seem to be firmly attached but some thin areas will flake. A heavy lime coating will coat it all.
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Dale Hodgins
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The bench sat for a week. It was supposed to be tarped during the day but that didn't happen. Quite a bit of cracking in the heat. The thin stuff on the back rest was cracked and cupped since the surface facing the sun dried very quickly. The thicker areas fared much better.

I scraped the thin areas clean and used a lime rich paste which is sticking better. The original cob was so eroded that there was little to bite into. I worked wet paste deep into the graveley original surface. So far about 90% of the work has been done by me since I can't use any help with the tedious process of crack filling, wetting and burnishing.

It's proving to be a major time sink, but not a bad way to spend the weekend.

This experience has further convinced me that cob production should be mechanized, built in one go and covered with a good roof with a substantial overhang. I did a test mix using a skid steer loader last year. It would take about 20 minutes to mix up enough cob for a bench this size. I'd rather start from scratch than fix another mess.

The next time I build a cob bench, it will be part of a heating system within a house.

Photos - Some ares are totally finished. Cracks are quite small and the materials have lost most of their moisture. The only worrisome part is the back rest. Even if it dries a bit crackled,I'll lock it together with many coats of lime wash.
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Dale Hodgins
garden master
Posts: 6704
Location: Victoria British Columbia-Canada
254
 
Dale Hodgins
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Posts: 6704
Location: Victoria British Columbia-Canada
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The bench has received many coats of whitewash. It's really thick on all of the high wear spots. The joints around the stone seat are filled up and lime paste is beveled between the back rest and seat.

The foundation stones got badly spashed and streaked on the first day but I was so busy with cobbing that I didn't notice everything the volunteers did. Two of the ladies helped totally coat the rocks yesterday since cleaning would take ages.

It's now the brightest, whitest bench in town. Before I had a chance to place the pylons for the night, a family sat down for a picture. The lime barely stuck to shorts and no harm to bench or bums.
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