Top 10 “Alternative” Construction Methods

by Dean Dalvit on December 17, 2013

There is a lot of conventional wisdom out there about what is “typical” for building construction practices. While the collective experience of available labor and availability of materials tends to drive how things get designed and built, it is important not to get stymied by routine practices. With progressive thinking about sustainable design and new ideas about how to manage construction costs, there are many new as well as old technologies that should be explored for the construction of a wide variety of building types. This post addresses my top 10 list of construction methods that, old or new, are considered by the industry to be “Alternative” (by the way, these are in no particular order):

1.) SIPs

SIP stands for Structural Insulated Panels. They are rigid foam insulation sandwiched between two OSB panels. They can be used structurally and create a wall or roof system with no thermal bridging. These buildings are extremely airtight and have very high r-value, resulting in superior thermal performance in a relatively thin wall. Multistory buildings can be done, but there are structural limitations to the panels as well as fire rated assemblies that need to be addressed for larger commercial use. SIPs can also be used as infill wall panels on frame structures.

2.) ICFs

ICF stands for Insulated Concrete Forms. They are continuous rigid foam panels that are used as concrete forms and left in place after the pour to create a wall that has both thermal mass as well as high r-value. Some contractors use these only for foundations, but entire structures can be built from them. These buildings are extremely quiet and thermally outstanding. Roof systems would have to be SIP, truss or rafter, so proper detailing is key. Cons are that local concrete costs can drive price per square foot significantly and these buildings are not easy to modify with conventional tools once built.

3.) Radiant wall systems

These are similar to ICFs, only the rigid insulation is an interior layer, sandwiched by the concrete layers. This places the durable concrete layer on the exterior and a layer of thermal mass inside the insulation layer, which results in a superior assembly. The interior layer of concrete also has hydronic  heat tubing in it, so they can serve as the heating distribution for the building. These walls have to be formed by a special crew trained in the system and as a result, will be more costly. Radiant wall systems are even more difficult than ICFs to modify once built due to the embedded hydronic tubing.

4.) Strawbale

These structures are essentially stacked straw bales that are finished with plaster, earth or stucco. Straw has relatively low r-value per inch, and not much thermal mass either, but the walls are very thick, so they make up for it. The walls are also very limited structurally. As a result, for anything other than small single story design, a structural frame would need to be incorporated to carry the loads and the strawbale walls would serve as infill material.

5.) Log

Log walls have been around for centuries and utilize solid wood logs as the structure and the finish. There are a wide variety of log coping techniques that range from very rustic with chinking serving as the thermal barrier between logs, to sophisticated milled logs that are very airtight. While wood has a relatively low R-value per inch, the thermal mass of the wall counteracts the loss in r-value. Detailing openings and interfaces to floor and roof systems are crucial to maintaining the thermal barrier in a log structure. Not commonly used in commercial building, Log structures can qualify for a type 4 construction and be used in certain fire assemblies.

6.) Timberframe

Timberframe structures have also been around for centuries. These are essentially heavy timber post and beam framed structures that require an infill material for the walls (SIPs are a good option). Craftsmanship is key in these structures and the joinery is nothing short of pure art expressed within the structure. Finding qualified labor can be challenging and materials need to be specially sourced. Like log construction, Timberframe can also be used in Type 4 construction.

7.) Cob

One of the oldest methods, and probably one of the most misunderstood, Cob has nothing to do with corn cobs. It is actually an earthen wall method of construction made of balls of mud and straw (Old English cobs) that are hand packed. This very labor intensive method of construction uses the cheapest of materials provided the native soils on the site are suitable. Walls can be scuplted in organic forms and need to be finished with a waterproof exterior so the rain won’t melt the structure away. The walls have very high thermal mass, which makes up for their relatively low r-value. There are structural limitations on cob construction, so a frame of some kind may be necessary for multistory or larger buildings.

8.) Adobe

Similar to Cob, Adobe is a clay brick method of wall construction. With suitable on-site soil, bricks can be made and dried then stacked in a labor intensive approach. Like Cob, you get thick walls, high thermal mass, but low r-value. Exterior finish is required to protect the wall and structural limitations still apply.

9.) Rammed Earth

Of the earthen techniques, Rammed Earth is seeing the strongest resurgence today. Made of a suitable recipe of soil that is compressed into a mold, the resulting walls are strong and durable. Like the other earthen methods, high thermal mass offsets low r-value, and the walls are generally much thicker. The resulting walls are very beautiful as you see the strata of the material as it was compressed into the form. These walls are significantly stronger than Adobe and Cob, and require much less maintenance.

10.) Earthship

Popularized in the 70′s, these structures are often made with used automobile tires, filled with earth. Infill walls would be recycled materials like glass bottles or aluminum cans and every effort is made to utilize local resources and eliminate waste. Portions of the building may be bermed or buried. The term Earthship really was intended to describe a sustainable approach to building, but over time, has resulted in buildings that have very similar characteristics and materials. With modern approaches to sustainable design, the sustainable design philosophy has outgrown the original structures, however, some are still being constructed today.

Epilogue:

It is not uncommon to see hybrids of these techniques used together, or combined with more conventional construction. There are also countless other methods that utilize both new and old technologies (some rather interesting – like corrugated paper construction, sandbag or even stacked carpet squares). There is no end to the inventiveness or innovation out there and every building site and type should explore all of the available techniques that may offer a higher degree of sustainability, reduced construction cost, and offer the owner or users of the building an opportunity for personal expression.

Originally posted 2010-01-15 10:28:29. Republished by Blog Post Promoter

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{ 6 comments… read them below or add one }

Dean Dalvit November 29, 2011 at 3:39 pm

Sherwood,

It’s clear that you’ve been putting a lot of thought into this! One of our Project Architects has done quite a bit of work on several University buildings in Saskatoon and we’re all too familiar with Canada’s heating degree days.

I agree that you would want to conceive the project with the most flexibility possible, given the rural nature and the financial possibilities. With the mix of uses, this can certainly be accomplished, however, the nature of finishes for a school with dormitories might make the alternate uses more akin to a youth retreat or public hostel rather than a 5 star resort. Nothing that couldn’t be re-dressed later, but everything has its price.

The best place to start from a ballpark point of view for cost estimating would be in the $200 per square foot range. We do quite a bit of University work and a private school has many similarities. See the post I’ve written on those project types here: http://evstudio.info/cost-per-square-foot-of-college-building-types-by-region/

Programming for the student body will have many variables to consider. Efficient dorm style housing could require as little as 100 sq.ft. per occupant with no communal living or dining space, which might be shared by the academic wing. Administration for the school could be as little as just a few offices and the classroom space could be as tight as 40 sq.ft. per student in an extremely austere environment. This would strictly be classroom space and would not include separate rooms for music, gym, art, computer labs, etc., which I assume you would want, and would easily double that requirement.

So, for 175 students, I would roughly estimate on the small side, a 35,000 sq.ft. facility. Of course, after fully programming all of the functional requirements desired, as well as all of the staff needs (do all of the teachers live on site? are there other amenities such as an indoor pool, etc.?), this number could easily double. so in round numbers, the project construction costs could range between $7 and $14 million. I know that’s quite a range, but at this level, is about as close as you can get without more programming.

It sounds like an exciting project, and we would love to be involved once you get to a point where you need to do any feasibility or concept planning. Let me know how we can help and we can go from there. Thanks!

Dean Dalvit November 29, 2011 at 3:38 pm

The continued conversation from the e-mail thread:
At this point it’s only a dream. No board. No money. No land. Probable location will be within a 2.5 hour drive of either Vancouver, Edmonton, or Calgary. Eventual size will be 150 to 175 students. (160 is one of the magic numbers for a private school in terms of economies of scale.) Likely it will be in a climate with 7 to 10 thousand heating degree days (Farenheit) with snow on the ground 4-6 months of the year.

I’m having a hard time tracking down ball park numbers. I’ve run into figures for college dorm space ranging from $65 to $130 per square foot, and high school space from $125 to $200 per square foot. Problem is nobody says how many square feet per student is needed. I know how big a classroom needs to be, but I’m uncertain about the things like hallways, and infra-structure spaces such as mechanical rooms, wiring closests, custodial closets, door clearances. There is a reason architects get paid good money.

I also haven’t been able to find out numbers on how much this can be reduced by intelligent design. E.g. tightly clustering plumbing. Or how much can be done with multiple phases — E.g. A core that has infra-structure, with dorm wing stubs on it that can be easily extended at a later date.

I’ve worked in 3 private schools, and visited a couple more. Architecture influences society. Kids need supervision. Idle hands and devil’s work, and all that. A building with lots of nooks and crannies invites bullying. As a duty master, I did as much with my ears as with my eyes. One school had staff apartments built into the dorms. These were occupied either by a married staff couple without kids, or by a pair of single staff. Meant that there were extra people on hand in the dorms during unstructured time. This was a big win, although fairly high stress on the residents. Most of the the time they were rotated thorugh this position after 1-2 years.

One school had two separate dorm buildings and an academic building. The net result was that kids had to ‘leave home’ in the morning, and spend the day at school. Another school was built in the form of an H, with one vertical stroke being the academics, and the other one being the dorms. The central cross bar was the infra-structure and admin offices. This worked better.

I was at Fortress Mountain ski resort near Calgary (since shut down — and I can’t find any pictures online.) The main lodge was 3 stories high, but the roof was composed of 5 hyperbolic paraboloids, arranged in a pentagon, canted so that the outside end was only about 12 feet off the ground, and the inside end was about 70 feet off the ground. The central space was the dining room, with a large fire pit, and a huge copper flue running up the centre. Rooms were in two rings overlooking the dining room. It would make it easy for someone in the middle to hear what was happening, and the multi-story made for shorter distances to get to a trouble spot. Bottom floor was kitchen, rental shops, offices.

Contrast that with one school I was at where it was 600 feet from the head master’s office to the furthest dorm. Practically needed rollerblades if you were duty master.

In college I was in a frat for a year. They did something interesting. They separated sleeping from living. The frat had two sleeping porches, filled with bunks pretty much like an army barracks. Then there were rooms, shared by 3-4 students each that had your dressers, bookshelves, old furniture, a place to study. The neat thing about this was that someone who wanted to study late didn’t keep his room mate up. Similarly the TV room was downstairs, a piano in a well soundproofed room of its own. This seems to me to be a good way to organize dorm life. Kids need space to be quiet. And a place to make noise.

From watching the finance committees at the places I’ve worked, it’s a LOT easier to get money for a non-profit building if the building can be easily repurposed for something else. E.g. it’s easier to get a load for a building that can be a school or a resort than it is for a school. This is one of the reasons I look at resorts and hotels carefully. This can show up as small changes in design at the outset. E.g. A stack of closets on multiple floors that can be turned into an elevator shaft later. Stub in plumbing for conversion to en-suite baths.

At one of the schools I was also chief of maintenance. I am a strong proponent of maintainable, modifiable buildings. If fiber-optic to each room becomes desirable in 20 years, it shouldn’t be a PITA to put it in.

Anyway, I’m babbling. Thanks for the tip on the Habitat for Humanity.

I’ll keep you in mind if anything ever flies with this.

Dean Dalvit November 29, 2011 at 11:57 am

Sherwood,

Thank you for your inquiry. In our experience, for the kind of building you are looking to build, that would have all of the functionality, but also the flexibility that you will ultimately need, it would be best to consider traditional framing techniques with materials that are easily sourced. Depending on the size of your school, even wood framing might be an option, and the skill level required for wood framing is relatively low. In fact, we have prepared framing drawings for Habitat for Humanity homes that were developed specifically for volunteers to build the wall panels by following the wall panel drawings. We did this special level of documentation for Habitat in order to allow them to use their volunteer pool that did not have the framing expertise you would get in a hired framer. It worked out great and in fact, most of the walls were built by students. See the link here: http://evstudio.info/students-at-platte-canyon-high-school-build-habitat-for-humanity-wall-sections-for-kindness-week/

We are very interested in educational projects and would be happy to discuss your project in more detail with you. If you could let me know a bit more about the project (location, size, budget, etc.), we could discuss options with you that would help inform your next steps. We are a full service Architecture and Engineering firm, and can help with everything from initial feasibility and concept planning all the way to engineering, construction documents and permitting, and everything in between.

Let me know how we can help!

Sherwood Botsford November 27, 2011 at 7:42 pm

How do you minimize construction costs?

Building a private boarding school for non-rich kids.. Money is tight.

The school will be rural:

1. Spreading out is ok.
2. Being one hour plus from the nearest labour pool means labour costs are about 25% higher.
3. Techniques that:
* Minimize use of skilled labour.
* Maximize use of volunteer labour (This builds a school community)
* Maximize re-use — mistakes will be made in design. I want to be able to redo the walls without breaking the bank.

Looking at this article:

SIPs mean that a good chunk of labour is done at the factory, less on sight.
Strawbale is labour intensive. Works well as a community builder, but other than the outer walls, it’s not a win.

ICFs mean that design has got to be right the first time.

Any guidelines to cutting the costs on such a venture?

Radiant Barreir February 18, 2010 at 10:43 pm

Thank you for the great post. This is the kind of information I am looking for and feel it to be of great value to all consumers. Most of the emphasis on energy conservation these days comes from the use of various products. But until we begin or return to designing correctly we will not be able to reap the majority of these saving. My favorites are the adobe huts that hold the suns heat from the daytime hours to warm the structure ducing the night and then begin this process the following morning. What an excellent example of great passive design.

Sean O'Hara January 17, 2010 at 2:45 pm

They are still building a lot of earthships around Taos. When I was there last summer I spent some time checking out the projects that were under construction. What makes them especially interesting is that true earthships are also built with rainwater harvesting, indoor agriculture, grey water systems, solar and of course passive ventilation. If anyone is interested I bought their books on their systems.

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