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Vapor barriers often create more damage than they prevent in straw bale houses. Why then are they required in straw bale building codes? The answer is not complicated; however, the impact of vapor barriers on homes of all types is.
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Popularity: 67%

When building a straw bale house, the question of what type of mesh, if any, should be used is a big one. I show the use of 14 gauge welded wire mesh in my DVDs, and that is a great option; however, it also has its downsides like any other application. For one, it is expensive. Secondly, it is a bit harsh on the environment to use so much steel. So, what other options are there?
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Popularity: 79%

On November 16th, I wrote a blog entry about retying straw bales, the new way! The new way is to use the Miller’s knot instead of the trucker’s hitch which has been used for years. In the first half of this two part entry, I showed you the basics of how the knot works and why I use it on all my straw bale homes. In this entry, I have included a video that shows you, in depth, how to tie the knot….well, you know what I mean.
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Popularity: 83%

When people consider building with straw bales, they most often find their top concern is how to protect the bales from rain. All too often, snow is not considered a threat to the structure. In most cases, this is true; however, in areas where large snow drifts are the norm, the impact of snow cannot be overlooked without consequence. It is typical that climates with a lot of snow, especially powdery snow, will eventually blow hard enough to create drifts. Those drifts will pile up on whatever interrupts their path, even if it happens to be your front door!
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Popularity: 53%

Today I received the following question and I thought it was worth sharing my response with you all. Here’s the question, my response follows:
“Well the time for using all this information is almost upon us. We are looking at a property at the moment to build on; however, it is quite a steep property. Do you have any ideas or photos of straw bale houses built on steep sites with out doing major earth work? Thanks in advance.
Regards Chris and Jenny”
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Popularity: 69%

Here are some questions I got from a client yesterday. I think they are worth sharing.

Q1. How much force is required to tie the bales tight. (my elbows are killing me)

A: The knot that I use, the Miller’s Knot (although I have been told that the name might be incorrect) is so strong that it is possible to tie the bales tighter than the original baling machine. This requires a strong twine as well as the standard twine often snaps under the added pressure of this knot. Super blue twine works very well. In general, I try to tie the bales as tight as I can. This usually means that when I am done, the old knots are slightly loose and the new twine is very tight to the bales. In terms of foot-pounds, I have no idea. IN terms of elbow pain, I would suggest a little less than what causes pain!

Q2. How to handle situations where you are only 3 to 4″ short and too small for a bale. How to stuff, how to lock the bales from moving and the use of tar paper under the bales and strapping.
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Popularity: 42%

Where welded wire mesh is used as the structural shear of a building, it is very important that temporary braces be used to secure the building before the mesh is applied. This is a common practice with conventional construction as well. 2×4 braces are used to support the walls and maintain a plumb line until the plywood is added. In a bale house, the system is a bit harder to deal with.
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Popularity: 32%

Gene wrote to me this week asking about the viability of retrofitting an existing structure with straw bales. I get that question a lot and figured it was time to blog about it. Any structure can be wrapped with bales, it is simply a question of how much extra work will be required to make that structure function properly once wrapped. Consider that you will be adding about 2′ to the exterior of the house and that all bale walls need to have adequate roof overhangs to protect them from rain. So, unless your house originally had 4′ overhangs, you will have to extend the roof to accommodate the bales. This means opening up the roof system and “sistering” new rafters to the old ones with enough attachment to support the cantilevered rafter tails. A good rule of thumb is that should be a two to one. If the overhang is 2′ then the attachment needs to be at least 4′ long. Of course then the sheathing will need to be attached and the roofing material feathered back into the existing roof.

Another area of concern are the window and door openings. These will end up recessed into the wall by the thickness of the bales, leaving a large sill that could collect water. Your options here are to move the windows and doors to the outside of the wall using standard bucks, or to slope the sills and cover them with some protective material that will quickly drain any water away from the house. Some options are concrete, granite, or finished wood sills. Doors don’t have this option because they don’t have room for sills.

Finally, will the bales collect moisture against the existing building? If the building is wrapped in a non breathable material like metal siding, the chances are high that the bales will end up soaking in the moisture that collects against the metal surface. A drainage system is a good idea in this case. Something like the product on this website (www.mortarnet.com) is a good idea in this application. Regardless of whether the back of the bales is separated from the existing structure by a drainage channel, the bales need to be fire proofed which means a layer of plaster needs to be added to the bales. This is easy on the face of the new wall, but the back of the bales will not be accessible once the bales are installed. For that reason, each bale needs to have plaster or a clay slip applied to the back before it is installed. This is a slow process, but an important one. The bales could otherwise present a fire risk if not covered. This is most important when using the drainage system but should also be done without a drainage system for added protection.

It sounds like a lot of work, but the results are beautiful and efficient. You may have to work hard to accomplish the wrap, but you will be paid back for years and years with lower utility bills, a more beautiful home, and a higher resale value should you ever decide to leave. I hope this gives you some ideas of what is needed for a bale retrofit.

Popularity: 30%

It is important that all wood surfaces be covered with roofing felt to separate them from the plaster. If you do not do this, the plaster will adhere to the wood and will be prone to extensive cracking as the wood dries and moves over time. a typical house has a lot of wood members that will need to be isolated so the process can be time consuming. It can also go quickly with a little planning and forethought. Here’s what I suggest. Figure out the major widths of the wood components that need to be covered with the felt. Add 4″ to that width for some overlap (I’ll tell you why in a minute). Now the roofing felt to the chop saw (use an old blade because the felt will gum it up terribly!)and cut the roll into smaller rolls matching the width you determined. Cut slowly to stop the felt from melting to itself rendering it useless. Now you have precut rolls of the size you need to move quickly through the structure. These rolls are not only cut to size, but also easier to carry around the job site and up ladders if necessary.

Now, why did you add 4″ to the measurement of the wood members? When notching your bales, I always tell you to over cut the notch rather than under cut it. If you try and hit the notch size exactly, you will miss most of the time and the trimming of the notch in the bale is hard to accomplish well. This means the bales will be harder to get into place and the time you’ll spend trimming, fine tuning and installing your bales will be huge. If you over cut the notches, you will speed the process immensely; however, you may end up with a bunch of 1″ gaps on the outside of the structure against the posts and beams where the over cut took place. You could stuff these, but it is hard (because they are only a few inches deep) and very time consuming (now you’re back to where you started with lost time!). The extra roofing felt (4″ over cut) acts as backing for the plaster as long as there is no more than an inch or so of space behind the felt. The other 1-3 inches of felt laps onto the bale, bridging the gap. There is no significant affect on the R-Value of the wall and the process is sped up greatly. Again, the faster you can move through the baling process, the sooner you can get the bales protected with plaster.

Popularity: 30%

When adding a straw bale addition to an existing straw bale house, you have to be sure to create a connection between the two walls (old and new). One way to do this is with dowels or rebar embedded into the old wall and laid in place in between courses of new wall. This allows you to leave the existing plaster in place and still accomplish a connection. Another way is remove the plaster from the existing wall and then use plaster lath on the top of each new course that is bent at 90 degrees and pined to the old wall surface. Use landscape pins on the old and new walls to attach the plaster lath. You will want to offset the new walls in either application so they are not in line with each other. In other words, add a right angle turn from the old wall and offset the new wall by at least one foot. This will help when you plaster because it gives you a stopping point (the corner). Without it, you will see a large plaster scar or will be required to plaster the entire wall (both old and new) to a corner.

Popularity: 29%

Do you live in a Tropical Rain Forest?

I am a big believer in the merits of straw bale construction. That’s probably obvious by now; however, there is one major drawback to working with bales: climate conditions. Bale homes are ideal for dry and mostly dry climates, acceptable in wet climates, and difficult to deal with in very wet and humid climates.

The big demon is not water, in the form of rain at least. In stead, it is humidity. Rain can be handled with proper design so even the wettest climates can accommodate straw bale structures. Humidity, on the other hand, cannot easily be designed out of a structure. It pervades everything and gets into everything. A bale house can stay dry from rain and still be saturated with moisture inside the plaster due to the acclimation of the bales to the area’s relative humidity. Everything eventually settles on a moisture content that is in direct relation to the relative humidity of its surroundings. Therefore, if the humidity is high, so too is the moisture content of your bread, your clothes, and your bales!

Let me give you an example, I used to live in Northern California, where humidity was often very high due to the coastal fog. My wife put her leather boots under our bed for a month and when she took them out, they were covered in green mold! Our house seemed fine and we surely did not expect to see that kind of mold anywhere near the inside of our house. But, the space under the bed is dark and has limited air movement, kind of like the space in between your layers of plaster.

What to do? Well, you must first consider if your climate is right for straw bale construction. If you have really high humidity and very little dry season each year, you may want to consider something other than bale construction. Another option is to consider mechanical help. If you install a whole house de-humidifier, you can minimize the amount of moisture in your house and therefore in your bales. Remember that when pressurized under normal living conditions, air moves out through the walls. If the air is dry, it is safe to pass through the walls. Systems like this can be installed into your HVAC system, if you have one, or can be stand alone units utilizing 4″ duct work.

Remember to design and build for the water and humidity. You not only need to design to keep water out, but also to allow it to escape should it get in (nature has a way of blowing even the greatest plans!) Plan for both, and you will be okay. Nevertheless, if you live some where that you think is too risky, ask for advice and then make whatever decision you feel is best around the use of bales in your home. And know that this is coming from some one who loves bale construction so I’m trying to talk you out of your dream!

Popularity: 30%

I have spoken before about the use of these easy application products and I want to once again speak in favor of them. The products are engineered and thus easily accepted by almost any building official. Their installation is relatively simple and speeds the construction of the home considerably. Be sure you know exactly where they will go in the house before you pour your foundation because the anchor bolts need to be placed in the exact spot in the concrete so they will properly line up with the panels during the framing stage. That said, it is possible to omit the bolts during the pour and drill them in later with the use of a rotary hammer drill and some rated epoxy. Some building officials may not feel as secure with this option; however, most companies that offer shear panels will accept this as a suitable installation of the panels.

Popularity: 17%

I just went through a humbling process on a new home construction project. I used a soils report prepared by a geotechnical engineer and provided by the land owner for a home site I was to build a custom home on. The soils report showed that there was fill from ground level to 3 feet down and that below that (from 3′ to 7′, the depth of the test pit) was “medium stiff, red-brown clayey SILT; moist.” That spelled out native soil to me and the report further stated that the foundation requirements for such soils were standard spread footers over a compacted rock base of roughly 4″ thickness.

Here’s where the humility comes in: I actually proceeded as if this engineered report was accurate. That seems like a fair assumption, but proved very expensive. The report was a couple years old, and when I compacted my gravel base on the site, the City wanted a new geotechnical report report they would approve the compacted fill and allow me to form my footers. I called my own geotech and asked him to come out for a site visit. he had us dig a test pit and when we did so, he was not convinced the soils that were quoted at 3′-7′ were in fact native. He asked my backhoe driver to keep digging. It was not until 13′ down that we knew he was right. We starting bringing up 40 year old garbage! The “soil” the previous geotech had identified was in fact 40 year old fill over an old personal garbage pit in the old property owner’s back yard.

A simple foundation changed to something very elaborate. We had to follow the native soils below the fill line all the way around the house and pour a sand/cement slurry to fill the now very deep, three feet wide holes. All of the rock had to be removed from the site so it would not end up contaminated and then replaced on the finished grade after the slurry was poured. The ultimate cost of this work was over $7000 and a time delay of one month ensued from the date of the geotech report request to that of completion of the new requirements. Yikes! So, know your ground. Know what is under your ground. Be certain that what you are building on is solid and can hold your structure. Although this was a slow pain in the rear end to deal with, I always prefer to deal with potential problems up front rather than having to fix them after the fact. The time and money spent on this project far outweighs the potential disaster that could have occurred had we not been required to get a new report. Of course, the fact that I relied on a previous geotech report is something of a frustration. The report, although 2 years old, should have been accurate and it was not. You can be sure I will write a letter to the company owner of the old geotechnical engineers on that one!

Popularity: 23%

Having built a number of straw bale houses now, my crews have started to focus on production. By this I mean they are always looking for ways to make the bale stacking, tying, and meshing go faster. We have developed a better straw bale needle in that effort (the plans for which can be purchased on my website), as well as other tools like “the salad fork.”
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Popularity: 20%

Here is a response to a student doing a case study of straw bale homes in North Carolina. He had a good question about how the bales of an existing structure in Alabama might be connected to the foundation. I think the details of the connection are worth mentioning here as well.
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Popularity: 12%

When you build with bales, one thing is almost 100% guaranteed: you will be plastering your walls. Knowing that, you may be surprised to discover that there is a cost that you should definitely put into your budget that may otherwise be overlooked. That cost is the electrical bill during the plastering phase.
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Popularity: 12%

There is a conversation happening right now on another list serve about woodpeckers destroying plaster on a house. This is not the first time I have heard of this. If you use earthen plasters that are based on local soils, you may encourage local birds to try and nest in your walls.
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Popularity: 11%

I had a very close call on a job I am working on this week. While I was in Maine on vacation, $10,000 worth of cork flooring was delivered to the job site and set for installation. My project manager noticed that there were blemishes on the cork and stopped the crew from installing it. He had the crew open a random number of boxes of the material and all of them had the same blemishes.
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Popularity: 9%

Wow. Time flies. It has been a week since I last posted and I sure don’t want to start making that the norm. Sorry to all you daily blog readers for the long gaps in between blogs. I have been really busy in the field and thus short on time at the computer. Anyway, let’s get to it!
We are currently building a house where the architect has called for base board trim to be used throughout. That is fairly standard delivery for most homes; however, is much more difficult in bale homes due to the undulations in the bale walls and the large curves in corners.
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Popularity: 15%

I was recently asked if it is possible to do an earthen or cement skim coat over a slab foundation. The answer is yes, you can do a skim coat of either clay/straw (earthen floor) or cement over the top of a concrete slab; however, there are minimum thicknesses that need to be maintained. At least 3″ of concrete are required unless a specialty skim coat is used (this takes extra skill).
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Popularity: 16%