Tag Archives: reconstruction

Northwest Corner Reconstruction Project: The Presidio Defense Wall takes on a new look!

by Mike Imwalle

Top: Crew from Modern Concrete pouring concrete for the upper bond beam and the gabled cap. Bottom: Finished concrete cap and pressure-treated ridge beam ready for tile.

In January of this year I reported that Channel Coast Corporation and David Tait Masonry completed laying the adobe bricks for a 60-foot section of the Northwest Corner defense wall. Once the bricks were laid to form the concrete bond beam at the top of the wall, it was Modern Concrete’s turn to climb the scaffolding to install reinforcing steel. On February 2nd the upper bond beam was poured and the gabled cap was formed.

Top: Cambron Roofing &Waterproofing roofer installing the cap tile along 60-foot section of Northwest Corner Defense Wall. Bottom: Cambron crew installing the last of the cap tiles. Photo by Mike Imwalle.

On February 13th Cambron Roofing & Waterproofing arrived on site to begin installing a self-adhesive moisture barrier to the top of the concrete cap. Composition sheeting was rolled on the top of the wall before installing the tile cap. On February 17th Cambron laid the last of the tiles for the 60-foot section of wall and, for the first time since Northwest Corner construction began in 2005, visitors can appreciate the size and scale of the outer wall. This section of wall was completed thanks to generous contributions from the California Community Foundation, Williams-Corbett Foundation, Jackson Family Foundation, and the Ahmanson Foundation.

In the coming months, crews will plaster the wall and SBTHP volunteers will whitewash it. SBTHP is embarking on a major capital campaign to raise the funding necessary to complete the Northwest Corner Project. It is the primary goal of the SBTHP’s Restoration Committee to finish the Northwest Corner Project so that its completion can be celebrated in conjunction with SBTHP’s 50th anniversary in 2013.


In addition to the cost to pay for contractors to build the wall, the SBTHP must also raise money to make the adobe bricks necessary to finish the project. To date, more than 11,700 adobe bricks have been laid to build the Northwest Corner Visitor Center and the 60-foot section of defense wall. We still need 8,608 more adobe bricks to finish the job. If you would like to help support the making of 8,608 more adobe bricks to complete the project, please visit the buy-a-brick webpage here.

Mike Imwalle is the archaeologist at the Santa Barbara Trust for Historic Preservation

Adobe Brick Making at El Presidio de Santa Bárbara State Historic Park

by Mike Imwalle

Josh Figueroa sifting dirt for adobe brick making. Photo by Mike Imwalle.

During the week before Christmas, SBTHP director and maestro adobero Tim Aguilar began preparing the Presidio site for making a large batch of adobe bricks for the reconstruction of the Northwest Corner defense wall. Crews immediately began sifting dirt  for the adobe mixture and grading the site flat for laying out the bricks. As soon as enough soil was prepared, crews began the process of mixing shovels of sifted dirt, water, straw, and a small amount of emulsified asphalt stabilizer.

The mixer crew adding shovels of dirt, water, and straw to the mixer. Photo by Mike Imwalle.

The site of the actual brick making is prepared in advance by laying out a series of wooden molds end to end and moistening them with water. The molds are constantly kept wet to prevent the thick mixture of mud and straw from sticking to the sides. Each mold has three rectangular reservoirs that will produce three 22 x 11 x 4-inch adobe blocks. The mud is delivered to the molds via wheelbarrows and dumped on to the surface of the molds.

SBTHP Director Tim Aguilar delivering a load of mud to the "punchers." Photo by Mike Imwalle.

The “punchers” scoop the excess mud out of the wheelbarrows and distribute it across the gang of three molds. Then, using their fists, they punch the mud deep down into the corners of the mold. This is a very important process to insure uniform size and good quality bricks with square corners. Once the mud is punched into the molds the excess mud is scraped even with the top of the mold and the surface of the brick is smoothed by hand. The mold is lifted off the bricks  and moved down to the end of the line to make another batch. Soon the site is covered with freshly made adobes ready to begin drying in the sun.

Punching and smoothing the adobe into the wooden molds. Photo by Mike Imwalle.

After laying flat for three or four days the bricks are tilted up on their side to maximize the amount of surfaces exposed to the air. This insures nice even drying and prevents cracking caused by the exterior of the brick drying faster than the center. After about a week of making bricks the entire site is covered, and we need to take a break to let them dry for about a month before we can stack them.

Lifting the molds off the adobe bricks. Photo by Mike Imwalle.

It is nice to have bricks all over site again. Brick making always generates excitement around the park and interest from the public.

Freshly made bricks spread across the front of the Presidio. Photo by Mike Imwalle.

I will be discussing more detailed aspects of adobe in future posts, including a closer look at the ingredients of adobe bricks, adobe construction, and the use of adobe bricks during construction of the original Presidio quadrangle.

Bricks tilted up on their sides to dry in the sun. Photo by Mike Imwalle.

Anyone interested in participating in an adobe brick making event please contact  Meredith Brockriede at meredith@sbthp.org to volunteer. If you are interested in supporting the Northwest Corner Reconstruction Project, visit the Buy-a-Brick campaign webpage here.

Mike Imwalle is the archaeologist at the Santa Barbara Trust for Historic Preservation. 

Northwest Corner Reconstruction Project: Rebuilding a Defense Wall, one brick at a time!

by Mike Imwalle

Northwest Corner rendering by Alex Eberle, Milford Wayne Donaldson Architects

After more than four years of intensive archaeological investigation, in 2003 SBTHP embarked on its most ambitious reconstruction effort since the organization’s founding almost fifty years ago. The Northwest Corner Project included the construction of new public restrooms, four adobe rooms to house a new Visitor’s Center, and more than 235 linear feet of outer defense wall. With completion of the restrooms in 2005 and the new Visitor’s Center in 2008 it was time to shift the focus of the fundraising and reconstruction efforts to the monumental task of the outer defense wall.

Reinforced concrete columns with sandstone foundations. Photo by Mike Imwalle.

In 2009 Channel Coast Corporation began the installation of 10-foot deep caissons to support 10-foot tall concrete columns. The columns would serve as the framework for the steel-reinforced bond beams that run the length of the 4-foot thick adobe wall.

Tait Masonry Crew laying adobe blocks on outer defense wall. Photo by Mike Imwalle.

With the concrete columns in place, David Tait Masonry began building a foundation of mortared sandstone to support the adobe walls. By October 2010 the foundation was completed, the first bond beam was poured, and we were ready to begin laying adobe bricks.

In January 2011 Tait Masonry laid a total of eight courses of adobe block on a 60-foot section of the wall closest to Canon Perdido Street and Channel Coast subsequently poured the second concrete bond beam. Work temporarily halted while additional funding was secured. In December 2011 thanks to generous contributions from the California Community Foundation, Williams-Corbett Foundation, Ann Jackson Family Foundation and the Ahmanson Foundation, construction of the wall has resumed.

Turning an adobe block for the "soldier" or "stretcher" course. Photo by Mike Imwalle.

Today the last bricks at the top of the 60-foot section of wall were laid. By the end of January Channel Coast Corporation hopes to have the upper bond beam and tile cap installed on this section and the adobe bricks laid and first bond beam poured for the next 60-foot section.

Exterior side of western outer defense wall. Photo by Mike Imwalle.

This wall takes an incredible amount of adobe block to reconstruct. So far we have laid almost 8,700 adobes in the Visitor’s Center buildings and another 3000 in the first 60 feet of defense wall. We still need more that 10,000 bricks to complete the project.

Top of adobe wall with concrete columns ready for bond beam and cap. Photo by Mike Imwalle.

Recently SBTHP director and presidio descendant Tim Aguilar and a crew made another 1,900 adobes.

Western outer defense wall at Canon Perdido Street sidewalk. Photo by Mike Imwalle.

Stay tuned next week for a post on adobe brick making and how you could become involved. If you would like to help support the making of 8,000 more adobe bricks to complete the project, please visit our buy-a-brick webpage.

Mike Imwalle is the archaeologist at the Santa Barbara Trust for Historic Preservation.