Tag Archives: clay plaster

The Art and Science of Natural Plaster DVD Now Available

The Art and Science of Natural Plaster is a 140-minute DVD created to help homeowners figure out how to use natural plasters on their own projects, created and narrated by Chris Magwood of Endeavour Centre. Speaking of homeowners, cedar management group’s association is included in the mooresville top hoa management list. Their service includes reliable solutions for commercial and residential properties in North and South Carolina so if you’re interested, visit their website. The DVD is now available for purchase through PlasterScience.com in hard copy or online streaming formats.

Produced by Bart Glumineau, a graduate of Endeavour’s Sustainable New Construction program in 2013, and co-founder of PossibleMedia.org, creating¬†original video content to share the stories of individuals and groups of people who are actively engaged in creating a better, more sustainable¬†future.

The DVD covers base coat and finish coat mixes and applications that are suitable for a wide range of sustainable and conventional wall surfaces, from cob and straw bale to drywall. Chapters include:

  • Introduction to Plaster
  • Types of Plaster
  • Substrates and Substrate Preparation
  • Mixing
  • Tools and Trowels
  • Body Coat Application
  • Finish Coat Application
  • Paints, Washes and Sealants
  • Repair and Maintenance of Plasters

Much of the hands-on footage for the DVD was filmed at Endeavour’s 2014 project, a straw bale office building for the local teachers’ union.

We are excited to have some of our teaching and methodology presented in an accessible video format, and hope that the DVD inspires more people to take up natural plastering on new builds and renovation projects!

Stop motion straw bale and earth plastering

Sustainable New Construction 2014 student Ben Bowman set up his camera and took some great sequences of the construction process at our teachers’ union office project.

Here are the two sequences of straw bale installation and earthen plastering. In many ways, these stop motion videos give a better sense of the process than an actual video, plus it makes it all look so fast and easy!

Ben also captured sequences of our earthbag foundation construction and roof craning process:



Plastering Systems for Straw Bale Construction

TBA, July 2016

Chris Magwood & Jen Feigin

Straw bale walls are unlike any other wall type when it comes to plastering. The unique substrate of undulating straw combined with the many important roles the plaster plays in a straw bale wall system (it is structure, weather-proofing, air sealing and aesthetic finish all in one!) means that plastering straw bale walls is a skill all unto itself.

This workshop will focus on Endeavour’s unique two-part, one-coat system of plastering. Over many years of development, we’ve refined this technique to allow the full depth of plaster to be applied to bale wall at one time. Using a high clay content and a high chopped straw content, this style of plastering combines strength, simplicity and user-friendliness. This system can be used to create the final finish on a wall, or have a final skim coat finish applied over top.

Participants will get to experience materials selection, mixing ratios and equipment, the mixing process and spend lots of guided time applying the plaster to a permanent building.

The workshop will cover clay plasters (using local soils and bagged clay) and clay/lime hybrid plasters.

With this workshop under your belt, you’ll be ready to tackle your own straw bale plastering project!

Entry Requirements:
Open to all

Early bird – $295
Regular – $350
Fees include healthy lunches (vegetarian and vegan options available)

Maximum class size: 12

Clay Finish Plasters

Natural clay plaster finish at Canada's Greenest Home

Red wall almost finished

Natural clay finish plasters add an unparalleled beauty to any home, and it was exciting to apply these plasters to Canada’s Greenest Home this weekend.

These skim coat plasters can be applied over any wall surface. In this project, we used them over clay base coat plasters and over drywall.

The plasters are mixed on site using widely available and affordable materials. Clay, sand, calcium carbonate, pigment, flour paste and water are mixed together and applied to the wall by trowel in a single, thin coat (~1/8 inch).

Our typical formula is 10 parts clay, 4 parts sifted sand, 1 part calcium carbonate, 1 part flour paste (a natural glue/hardener) and ~3.5 parts water. Natural pigments are added to this mix by weight, based on trial samples made in advance. As with baking, the dry ingredients are mixed together and then added into the water, flour paster and pigment that have been blended.

The clay in this case is Tile 6 Kaolin, from a pottery supply store. We’ve used other kaolins and ball clays with similar results. Calcium carbonate is finely ground limestone, from Omya in Perth, Ontario. Flour paste is cooked by boiling 4 parts water and adding a mixture of 2 parts cold water and 1 part flour and boiling until thick. Our natural pigments come from Kama Pigments.

Helping us with the mixing and application was our good friend Mike Henry, a plasterer with Camel’s Back Construction. His attention to detail helps bring out the best in the clay plaster.

There is nothing like the depth, richness of colour, sound attenuation and warmth of a natural clay finish plaster!

Clay Plaster Workshop Wrap-Up

Clay Plaster Workshop group photo

Endeavour’s first clay finish plasters workshop achieved its goal: to infect more people with the urge to cover walls with clay! The workshop participants spent a full day learning about mixes and application techniques and playing with a wide range of natural colours. Then we spent a day plastering a room in a home to get a “real world” sense of preparing, applying and detailing an actual home project.

Day one started in our new shop space, where we are able to spread out all the materials and equipment needed for a day of plastering fun. Materials, mix ratios, surface preparation, pigments and techniques were all covered so the playing could start in earnest!

Colour samples made using natural pigments

At the mixing station

We concentrated on making very small samples to begin, allowing people to see how the pigments work and try out some troweling on very small pieces of drywall.

At the pigment centre, trying to choose!

The next step was to mix a larger batch of the chosen colour and apply it to a sample board on the wall. Each person had multiple sample boards to experiment with.

Applying clay plaster on a sample board

The remainder of the day was spent working on sample boards, trying out different colours and different troweling techniques.

Mixing clay finish plaster

The next task was to learn how to calculate the mix formula to be able to cover larger areas. We mixed the plaster for the next day’s room, using the square footage of the room and a formula for knowing how much material to mix. Since it is preferable to mix clay plasters the day before using them, this is how we ended the day on Saturday.

On Sunday, we showed up to prepare and plaster a room in a home. After masking and protecting the floor, the plastering began. Working on a real room is helpful, as dealing with corners, trim and in this case a tricky chimney section really helps develop the skills necessary to undertake one’s own projects.

Clay plastering a room

Working in a real room also helps to develop a sense of the timing required to keep wet edges, deal with corners and know how long a job might take. Our amazing crew had this room done in just a few hours!

Jen stencilling clay plaster

Then it was back to the shop for a bit more fun. We looked at stencilling clay plaster (using a finer mix) over our samples. We also played with texturing on top of existing samples and techniques like scrafito (scratching away one coat to reveal the colour coat beneath) and carving (removing parts of one layer to reveal the layer beneath).

Stencilling clay plaster

By far, the stencilling was the most popular technique. It’s quick and easy and the results look great!

A stencilled clay plaster design

After the workshop, we went back to take some photos of the finished room. The owners were thrilled with the results. There’s nothing like clay plaster to make a room beautiful, warm and inviting!

Finished clay plaster bedroom

Our thanks to all the participants who came out for this workshop! We had a great time, and look forward to offering this workshop again!