7 Reasons to Keep Your Old Plaster or Plaster New Walls

You could say that lime plaster forms the foundation of our company, or at least of our origin story. The three of us met on a big lime plaster job in the mountains west of Boulder, CO. We each contacted our mentor, Ryan Chivers, because we had heard of his reputation in the natural building community as a lime plaster expert. Frank had worked with him for a year at that time, and this project was mine and Ben’s first time meeting Ryan. He brought us on to help him sling plaster on both the exterior and interior of this strawbale mountain home. And, as they say, the rest is history.

Here are a few of the reasons we love lime. Whether it’s found in a historic home where plaster was the primary choice for wall building at the time (lime or gypsum), or a new build or remodel where the homeowner chooses to use plaster, this material is definitely not out of style.

1. Beauty

Have you heard the word birefringence? I hadn’t either, until I met Frank. Wikipedia defines it as so: “Birefringence is the optical property of a material having a refractive index that depends on the polarization and propagation direction of light.” Well, maybe that cleared things up for some of us…

The point is, because lime plaster cures back to it’s original material of limestone, it maintains some of the aesthetically enchanting qualities and depth of a natural gemstone or mineral, while being customizable in texture and color.

2. Durability

We all know that something that’s rock solid is very dependable. So, if someone gave you the choice to have walls that are literally rock solid, wouldn’t you take them up on that? It sounds like a no brainer to me.

3. Easy to Repair

One miraculous feature of lime plaster is that it is actually constantly repairing itself on a microscopic level. When small cracks form, new lime is exposed to air and moisture, which causes a continuing reaction which can self-heal smaller cracks. In case your lime plastered walls do get some bigger cracks, or a couple scratches, or an historic wall system needs repair, lime plaster can be repaired by a skilled plasterer. There are even artisans replicating plaster relief art in historic renovation.

4. It’s got History

Today, I told a material supplier that the products I was picking up were going to be used on a exterior plaster job, using lime plaster. He looked surprised and said, “Now that’s old school.” And he is not wrong! But the best thing about an old school material like lime it that it’s tried and true. And lime has been used in building mortars and plasters since the Greek and Roman heydays.

5. Low Carbon Footprint

As lime cures, it actually absorbs CO2 from the atmosphere. While there is still energy input during the production and shipping of lime (we call this it’s embodied energy), the curing process helps to offset this carbon footprint. Plus, lime is a more local product in many locations, particularly here in the Denver area, which means less fuel is burned for transportation than a cement stucco or paint.

6. Support your Local Craftsmen and Craftswomen

Many trade groups and magazines are extolling the virtues of skilled craftspeople in construction. The hashtag #keepcraftalive is one example I saw recently. Like many trades in the building industry, the workforce of skilled plasterers is diminishing. Hiring a local plaster company is one way to help rekindle the movement of skilled laborers coming up in the workforce. Plus, dollars spent on local products and with small businesses are more likely to stay in the community.

7. Improve Indoor Air Quality

Plaster improves indoor air quality in a few ways. One is that lime plaster contains no chemicals that can off-gas into the indoor atmosphere. Those are things like VOCs (found in some paints and stains). Instead, plaster is made of solely natural materials like sand and lime, with nothing that will emit noxious chemicals into the home.

Another way plasters improve air quality is managing humidity levels. We wrote a full blog on plaster and humidity over at our plaster specific website, Living Plasters. The general idea is that whether humidity is too low or too high, it can be bad for indoor air quality, or make your home feel uncomfortable. Plasters act as a buffer to moderate humidity levels in the “Goldilocks Zone” of just-right.

lime plaster door

Personally, I’m excited to be part of reviving the lime plaster movement and beautifying our homes and buildings.

Our Lime Plasters Featured in Modern in Denver Magazine

Living Craft’s work at The Bindery Restaurant in Denver was recently featured in an article in Modern in Denver magazine. The focus is on the sustainable and cultural elements that the owner, Linda, brought to her new business venture. Our custom traditional lime plasters are one component of the sustainability practices that they prioritized during their design and build process. Read the full article to find out more, or stop by for an up close look at the walls.

The Ties That Bind


“Lime Plaster is a natural product. It’s a true craftsman’s product… it’s more alive than stucco. It allows light to interact, to dance.”

Read the Full Article 

Case Study: A Straw-Cell Addition

straw wallsLiving Craft Design has been working on a straw bale addition to our friends’ home in Boulder. This family is already well-versed in the benefits of natural building, so their addition incorporates passive solar heating with large, south-facing windows and a concrete slab floor to hold all that sun-generated heat. The addition has the high insulation value (R-value) that is a great feature of straw bales as a building material. Additionally, the family chose to renovate the original rooms of their home and filled the walls and ceilings with densely-packed blown cellulose as part of that process. This home will be comfortable year-round and have low energy bills as well as a reduced need for running heating and cooling systems.

 

A Straw-Cell Design

We jumped into the project starting with straw bale installation. This house has what’s called a straw-cell wall, with an entire wall system behind the bales, complete with wood studs, recycled denim insulation, and exterior wood siding. The bales then are stacked on the inside of this wall, meaning that labor is reduced because you don’t have to cut or trim as many bales to fit within and around the walls’ wood frames. You also only need to apply plaster to the interior side of the bales.

Low Carbon

A great thing about the insulation materials used in this home is that they are all carbon-based, and will now be locked away in the walls of this home for a very long time. This is actually a form of carbon sequestration, one technique to keep atmospheric carbon down and help mitigate climate change. This is in direct contrast to insulation materials like foam, fiberglass, and mineral wool, which consume a lot of energy to create. This means that the manufacture of those materials produces a lot of greenhouse gas emissions, upping their carbon footprint.

Healthy, Natural Plasters

Applying a base layer of clay plaster at the work party.
Applying a base layer of clay plaster at the work party.

Our next step was to start the plasters. A base coat of local red clay was applied to cover the bales first. At a fun summertime work party hosted by the family, we added a leveling coat which will provide the base and shape for the finish plasters. We introduced some folks to the techniques and tools for mixing and applying natural clay plasters and played in the mud with good friends. We also started to build out the windowsills into their final shape using a lime and clay mixture with lots of straw for strength.

Ben talks building with some volunteers while others work on shaping the windowsills.
Ben talks building with some volunteers while others work on shaping the windowsills.
The finish plaster drying around the laundry room window.
The finish plaster drying around the laundry room window.

The final wall finish was customized to get the exact color and texture that our clients wanted, and this last, thin layer of clay-based plaster went on like a dream. Thanks to additions like wheat paste, it dries into a hard and durable finish that will last for years, and also be easily reparable in case of accidental damages.

During the wall finish process, we were preparing for and creating the tadelakt windowsills that will become perfect benches for sitting on and reading in the natural light. This Moroccan finish plaster is created from lime, which is why the base coat for the sills incorporated lime with the clay. This results in a tight bond between the materials. The smooth layers of lime were applied, soaped, and burnished using stones to create a shiny finish. The sills were then waxed as the final step to create a long-lasting surface that can withstand some use.

The burnished and waxed tadelakt windowsills have an amazing shine and reflection, as well as feeling silky smooth.
The burnished and waxed tadelakt windowsills have an amazing shine and reflection, as well as feeling silky smooth.

The End Result: A Beyond Green Building

We’re departing this project with lots of hope for the future which will unfold in this family’s happy, healthy, non-toxic, and environmentally friendly home. Not only will it be a beautiful space to raise a family, but also a good model for other front range homeowners looking to sustainably add some space and renew their original home.

finished window and wall plaster

Case Study: Repairing a Strawbale Home

after-sponge-coat
The home after we applied a thin lime plaster over all the repairs.

Our clients for this project had finished building their own straw-bale home in the mountains west of Boulder about a decade ago. However, the harsh mountain climate and some details of the design and material selection had led to failures in areas of plaster, particularly around windows and in places where the roof drainage lacked adequate gutter systems.

lime-stabilized
The lime-stabilized earth layer which was used to repair damaged areas of the home, seen as the darker, lower level in this picture, has been built out by the homeowner to the same level as the original lime plaster. Now it’s ready to get a thin lime plaster over them all, to blend the different sections of the home together.

We worked with them to come up with a solution that would allow them to participate in the repair work, while using our experience and tools to speed up the process and get the home ready for winter.

First steps were to remove the lime plaster where it had begun to delaminate from the clay plaster base coat below. This happens because of a reaction between the two materials that creates a silt layer which prevents them from bonding, weakening the walls. In some areas, water had eroded the clay base coats, and we needed to mix and apply a clay plaster to build out everything to the same level. Next, we mixed up an intermediate lime-stabilized earth plaster to apply on top of the clay base coat. This in-between layer helps bond the two materials by creating a transition. The homeowners applied both of these layers by hand after we mixed up several batches and staged them around the house. They also took the opportunity to enhance and add some sculptural elements, including the house number in relief on the side of the wall.strawbale-home-number

We also added metal flashing around windows and below siding to move any water running off the building out to the surface of the wall and keep it from infiltrating into the plaster again. A final sponge-finished lime plaster over the whole house covers up any differences between the old and new and seals boundaries to prevent water from eroding the surface.

strawbale-repairs-in-progress

We will be able to go back in the spring next year, once temperatures are consistently above freezing, to apply a final colored coat over their home. This entire process will ensure that the will last for many decades to come, even in the harsh mountain winters.

Bathroom Remodel Before and Afters

We tackled a big project earlier this year with the complete remodel of a bathroom in Denver. The bathroom had been updated back in the 1990s, and it definitely looked a little dated. More problematic, there were moisture issues which resulted in peeling wallpaper, water stains in the foyer below, and the potential for greater damage. The homeowner needed an update, not only in the style of the bathroom, but also with its functionality!

We worked with our client’s needs and desires, and came up with a modern new layout and design that incorporates lime plasters, including Moroccan tadelakt for use in the shower and custom built sink basin. Also new are the coordinating wooden cabinets, trim, and door, and large format tiles on the walls and floor, plus pebble tile in the shower basin.

For improved building performance, we installed a new motion-detector equipped ventilation fan to move moisture to the outside of the home, fully waterproofed the shower walls and floors, and added blown cellulose and improved air sealing in the attic. An energy audit, performed both before and after upgrades, confirmed that the home will now have lower heating and cooing costs. These performance upgrades also allowed the homeowner to claim a rebate with their energy company.

Check out some of our before and after shots to see the differences!

Before after door
Take note: this shot is in after/before order!

Before after sink

Before After vanity

Before After Shower

before after niche