Applying the clay plaster base coat to faswall block

This spring is all about plaster. I’ve been hired to complete the plaster work on a faswall block home in western Kentucky, including the clay plaster interior and a lime plaster exterior. There’s 3500+ total square feet of wall between the interior and exterior, which is no slouch. I just returned home from completing the clay and lime base coats with our crew. It was a big push and I’m glad to be done… well, at least until it’s time to go back and apply the finish, anyway.

Read on to see some images of the base coat clay plaster on faswall block!

Clay Plaster on Faswall Block

From a distance, faswall blocks look like regular ol’ concrete blocks, but they’re actually made with waste wood chips impregnated with clay and bound with cement, so the overall concrete content is much much lower… and best of all, they’re actually insulative. They’re dry laid, lined with mineral wool, and then backfilled with concrete. They have a very porous surface, perfect for a plaster finish. In fact, they’re really pleasant to work with because the wall surface is quite flat to start with, and the suction is very good.

The biggest interior wall getting a base coat clay plaster applied

The same large wall, freshly completed

We ended up doing a 3/4″ thick, straw-rich clay plaster base coat on the interior. I decided to embed fiberglass mesh to ensure even greater durability. Creating a smooth, flat plane was fairly simple given the nature of the block wall. If you’ve ever tried to create a flat plaster finish on a straw bale wall, you’re aware that it entails a lot of work and lots and lots of material to deal with the natural undulations of the bales themselves.

A look at the window detailing

Honestly, the biggest difficulty was installing all of the window and door trim, baseboards, and other plaster stops prior to plastering. It took almost as much time as it did to actually plaster the walls themselves. The couple decided to use reclaimed windows, which were not sized exactly to the openings in the block walls, so they needed a lot of work before we could even think about installing the trim and laying the plaster. We all agreed, hands down, that new windows sized to fit the exact opening are far far better (and ultimately far less expensive) than spending hours messing around with reclaimed windows.

I love the look of freshly applied clay plaster… it never gets old.

The Japanese jigane application trowels I purchased from Kyle (from JapanesePlastering.com) got an excellent workout and they certainly proved themselves to be phenomenal tools. A high quality tool always makes the difference, ya know? They were a treat to use.

Here are some of the jigane application trowels we used

Once the base coat dries out, we’ll return to do an American Clay finish coat, which I’m excited to try out.

Look out for a post with photos of the exterior lime plaster!