If you have ever wondered why you don’t see a lot of steel framed straw bale homes, the answer can be summed up in one word: condensation. That does not mean that a bale house cannot be built with steel framing; however, it does mean that special care must be taken to protect the bales from condensation. I have outlined the easiest way to accomplish this below.
Archive for the ‘Framing’ Category
Those of you who receive our newsletters already know about our upcoming framing DVD and the FREE Framing Report that we are offering to people to “wet their whistle” for the details of framing a straw bale structure. The report is an excerpt from my upcoming book: A Modern Look at Straw Bale Construction Details and is full of juicy details about what it takes to frame a bale house. It’s a big report too, not just a bunch of pictures and a few notes here and there. It is 34 pages long and has 12,442 words detailing the process. I tell you about the number of words so you can see that it’s the real deal.
Funnily enough, Gabriella (my wife) mentioned to me today that I had not written anything on the blog about the framing DVD or the FREE report. That’s crazy! After all, this is our own website, you’d think I would tell people about the products we are creating. Sorry about that. I guess I just got used to communicating through my newsletters and forgot to put the information up here too. Anyway, here it is, the information on the upcoming DVD sale and a link to get your own FREE copy of the framing report.
The Framing DVD is a 2 DVD set, with 2hrs and 53min worth of detailed instruction on how to frame your own straw bale structure. In it, you will find a step-by-step teaching style that will walk you through the entire framing process from start to finish. We have done everything in our power to provide this information in a manner that will be easy to understand to even those with no previous framing experience. We even have a bonus section dedicated to breaking down each framing term so that you don’t get lost by the technical terms while watching the DVD.
I hope you’ll take a minute to check out a short preview of the DVD so that you can get a glimpse of what the footage looks like. Below, I’ll lay out the details for the upcoming DVD launch sale and how you can get a great price on this awesome new production.
But first…let’s talk about the FREE Framing Report.
It all started with the creation of my upcoming book, but accelerated into this FREE report when I asked myself: what are the five most important details I would share with anyone interested in framing a straw bale structure? I have been teaching people all about these details for years at my workshops, but I realized I was missing the chance to teach even more people, those who cannot make it to a hands-on class. So, I came up with my top five and put pen to paper (or in this case cyber-pen to computer). I have had over 1900 people download the report already and the feedback has been amazing. I trust you too will enjoy the report and learn a ton in the process.
For those of you who are wondering, I want to be totally clear that this report is FREE. You can give it away to anyone you want to, if you so choose. You are under no obligation whatsoever to buy my book or my DVD. I simply want you to learn how to do these five important framing details. Period. So, if you want to get the FREE report, please click here. You will be taken to a new window, so don’t forget to finish reading this page as all of the details of the upcoming Framing DVD Launch Sale are coming up right now…
Okay, check out the below details for the upcoming DVD launch sale:
- Our Launch Sale will go Live at 6am, Friday, July 6.
- The sale will end promptly at 6am, Thursday, July 12.
- In the sale you will be able to buy our DVDs at 30% Off retail for the first DVD and 55% Off for each subsequent video.
- Look for the new Combo Package which will save you nearly 70% Off retail costs.
- There will be a sale on our Plans as well, including our brand new Mountain View Cabin design which are the plans we used to frame the cabin on the Framing DVD.
- We will send out an email at 6am this Friday morning to our newsletter subscribers with your sales link in it. If you want to be included in that email, please be sure to either sign up for our FREE 7-Day E-course or download the Free Framing Report so your name will be included in our announcement.
Excerpt from the chapter “Water Isolation Walls” from A Modern Look at Straw Bale Construction Details by Andrew Morrison:
Water Isolation Walls
Water is the biggest enemy of straw bale construction. It comes in many forms from humidity to broken plumbing lines, but the results are the same: damage to the bales. Because water is such a major player in the construction of any home, we have to be careful how we intertie the two systems of bales and plumbing. One way is through the use of water isolation walls. (more…)
Hey everyone! This is Gabriella, Andrew’s wife writing. I wanted to share a preview of our brand new video, The How To Guide To Framing For Straw Bale Construction. The video is nearly 3 hours long and will be contained in a 2 DVD set.
We genuinely had fun filming this production and we were graced by nearly perfect weather as well as a backdrop of a gorgeous snow capped mountain peak. The footage looks excellent and I have just completed editing it. All that’s left to do is to encode it, burn the master DVDs and send them off for replication. So, I think we will have them in hand in about 4 weeks!
Here’s the 8 minute preview which contains snippets of the footage
There may be no more beautiful look than a timber frame house wrapped with straw bales and plaster. It’s as if the two were made for each other. Although the look is fantastic, the actuality of creating that look can be a bit troublesome if you don’t approach the project from the right angles. There are most definitely some differences in techniques when it comes to creating a straw bale wrap on a timber frame house. Get it wrong and the look will still be there, you will just end up more tired and frustrated than you need to be!
I can tell you that the techniques you need to include are simple and that with proper execution, you can have the look you want. What I can’t tell you, via a blog post or email, is exactly how to implement the techniques. That’s because seeing it and doing it in person is much easier than describing it in words. That said, here it goes…
The biggest secret to timber frame and bale unions is to be sure to create a tight joint between the two different materials: wood and straw/plaster. If you don’t do that, you will get cracks at every joint and those cracks will become areas of moisture infiltration into the bales, increasing the chance of moisture damage. The best way to do that is to install plaster lath, also known as blood lath or diamond lath, to the back side of the posts and beams before you install the bales. Hang it over the edges of the wood by about 3-4″. This will allow you to tie your mesh into the lath and then have a tight, structurally supported plaster/wood joint later on. You can see the lath extending beyond the edge of the post in the picture to the right (not the 2″x2″ mesh, but the tighter lath).
Secondly, you’ll need to attach the bales to the frame in some way so they don’t simply peel away from the structure over time. The easiest way to accomplish this is to use a fold of plaster lath on top of each course of bales and at every post intersection. Simply fold a roughly 9″ wide x 18″ long section of lath in half so that you end up with a 12″ fold and a 6″ fold, 9″ wide. The 12″ section lays on top of the bale course and the 6″ section is stapled to the post on the back side. With the bales in place, the 12″ section is then stapled, using 9″ landscape pins to the top of the bales. This creates a positive connection between the posts and the bales. You can see an example of what I mean in the photo to the left. This is a corner on a building with bales on edge, so the lath is not as long as 12″ as mentioned above. Same concept though.
Like I said, this is not easy to describe in words, so I hope I’ve done it justice. There is more to it than this. This is just the tip of the iceberg as they say and the basics that you’ll need to know about in order to create success with this style of design. Again, the best way to learn the ins and outs is to get some hands on experience with a structure that uses this technique. If you’ll forgive the plug, I want to mention that I am teaching a seven day straw bale workshop May 16-22, 2011 on a timber frame house in Caledon, Ontario. This would be a great opportunity for anyone interested in learning how to do this right for their own structure. I’m sure the host would be happy to answer questions about the frame itself as well. Hope to see you there, and if not, I wish you the best of success with your timber frame/straw bale project.
If you have interior partition walls in the straw bale structure you’re building, you’ll need to attach them to the structure before you install your drywall on the interior walls. Keep in mind, I’m not talking about drywall over the bales, just on the interior framed walls. The two biggest problems with interior partition walls in straw bale houses are:
1. The stud that sits on the plane of the bale wall where the two walls intersect is in the way when baling.
2. There’s nowhere to nail mesh along the wall intersection.
I’ve outlined how to deal with both of this issues in this post. The picture above is descriptive of the solution to the second issue.
To handle the first of the two problems, all you have to do is plan ahead. Cut your studs and build your interior partition walls; however, leave off the studs that intersect with the bale walls. Spray them with Bright Pink or Orange spray paint with the word “SAVE” and place them near the partition wall to which they belong. If you have several walls with varying plate heights, you can label each stud with a letter or number that corresponds to the wall to which they belong.
Now that the stud has been set aside, you can build the detail that’s outlined in the drawing above so that you can solve issue number 2. Cut a piece of 5/8″ or 3/4″ plywood so that it fits in between the top plate/beam assembly and the toe up. It should be wide enough to extend 6″ past each side of the stud. It does not have to fit tight to the beam assembly or toe up. Just cut it so that it’s within a couple inches of each when installed. Cover the face of the plywood with roofing felt. Now attach the plywood to the stud by nailing through the plywood into the back of the stud. Be sure the roofing felt is facing the stud and that the plywood is centered properly in between the plate/beam assembly and the toe up.
You’ll need to notch the bales to allow the plywood to sit in them such that the face of the plywood/back of the stud is flush with the face of the bales. Now you have a stud that you can attach the drywall to AND you have nailers on either side of the stud to attach your mesh to. Because the nailers are 6″ wide, you can install the mesh before or after the drywall has been hung. This helps speed up the process because if you hire a drywall sub, they can get to work while you are still baling, moving the whole project forward faster.
I’m not a big fan of bales in the roof as you likely already know. They are so heavy and there are several areas of concern in regards to using them above head.
1. The frame needs to be drastically increased in size and/or spacing to support the extra load.
2. Plastering over head is VERY difficult and tiring.This can be alleviated by using planking in place of plaster for the finish.
3. The R-Value gained is not anything better than what you can get with regular insulation materials (either blown in or batts and either natural materials like cotton or wool or conventional ones like fiberglass).
Personally, I stick with light weight insulation materials in the roof and leave the bales for the walls; however, if you want to use bales, you can use an assembly that looks something like this:
- 2×6 tongue and groove planking over beams/girders (to be engineered per the loads and spans)
- Double layer of drywall as described for boiler rooms, etc.
- Vapor barrier as required. I’m not sure what options you actually have for this and may end up with plastic sheeting as the only option.
- Bales dipped in lime plaster to provide fire protection for the bales themselves.
- 1″ Plywood
- 1.5″ air space
- 2×2 wooden nailers secured with 18″ (min) panel screws to the 2×6 wood planks and the beams below the bales.
- 1″ Plywood roof decking material.
- Living Roof Assembly with 2×6 Rim
- Underlayment and pond liner wrapping over the edge of the rim boards.
- Chicken wire over rim board edges to secure the soil and living roof in place. Be careful not to puncture the pond liner inside the rim boards. Nail the wire to the outside of the boards only and fold all sharp edges in before installing.
This system can be done, but it will be very expensive in the cost of wood or steel framing required to support the extra loads of the bales and the living roof. You will definitely need to have an engineer design this frame. Once again, I think you’re better off sticking with conventional insulation materials in the roof, especially if you plan a living roof as that is heavy enough on its own.
Lots of people want the look of adobe homes when they build with bales. The biggest risk to that is in the inset window details. If this detail is not properly constructed, there’s a good chance, not just a small chance, but a good chance, that you’ll end up with water damage beneath your windows. I’ve posted a sketch of a quality flashing and construction detail for this application that will help you ensure water tight seals around your windows.
The detail is for a house that has plaster finished tight to the windows. If you wanted to add a sill of some other material, that is absolutely an option. The key is to use supported bituthene under the windows and over the bales. This way, it’s not going to get poked by the straw over time and end up with holes in it. The outer framing and inner framing help keep the entire unit in place and solid, again, protecting the longevity of the flashing. Be sure to counter flash (adhesive flashing installed on the jambs and sill, before the window is installed. Use the absolute minimum number of nails or screws to fasten the bottom of the window. Some windows don’t allow you to nail the bottom flange at all, so read the manufacturer’s recommendations.
Once the window is installed, lay a large sheet of adhesive flashing (bituthene) over the window flange and out over the edge of the plywood base. Turn the edge of it down over the outer frame so that any water will drain directly to the plaster, not into the bales. Install the side adhesive flashing and then the window head flashing in that order. I prefer adhesive flashing all the way around. Finally, install a J-metal or custom metal flashing under (and around) the window to create a clean stop for the plaster. Use the bare minimum fasteners for this flashing. If possible, only nail it in two places, outside the window frame by extending the legs of the J-metal wider than the window but while keeping the J channel in line with the rest of the flashing around the window. In other words, the j channel should miter in the corners with the vertical pieces yet the nail plate of the bottom piece can extend out beyond the window frame. Sorry, that’s hard to describe and much easier to show in person at a workshop!
Although the image shows the J-metal out in front of the window flange and frame, it will actually be installed under the window so that water cannot drip in behind it. I had to “explode out” the view so it would make more sense. You can place a bead of clear caulk in the joint between the window and the flashing for extra insurance. Hope that all makes sense. As I said, it’s easier to show you in person than on a blog.
Here’s a great tip for framing a post and beam structure where the framing will be buried in the bale walls. This is something my crews figured out a couple years ago and I’ve been trying to find the best way to explain it: video, drawings, teaching people at workshops, etc. Finally, I’ve decided that I just need to write about it and give you a hand drawn sketch to get the ball rolling. I’ve been teaching it at workshops for years, but have not had time to make a video about it. So, here it is:
The concept is taken from conventional framing where the walls are built on the ground and then raised into position. One of the biggest problems with building post and beam houses is that all of the posts need to be plumbed and braced as they are installed and then checked again after the beams have been set. Once the beams are in place and the post are locked into position, the bracing can come off. That bracing, although used in other places on the job site, often gets broken or thrown away and that’s a big waste. So now, you’ve got wasted limber and slow going. Sounds like a poor way to start the job.
Here’s how our system works. Take a 2×4 and tack nail it to your bottom plate (in this case, your 4×4 which will be part of your toe ups). Complete the framing layout on the two pieces of lumber just as you would during conventional construction. In other words, mark the location of all the posts on both pieces of wood: the bottom plate and the top plate as shown in the image above.
Now separate the two plates and place them on the floor system (slab, framed floor, etc). Insert your posts per the layout and attach them to the plates. Now you can stand the wall in one long section (or several sections depending on the wall length). The key here is in the plumbing of the wall. Because your layout is exact on both plates, all you have to do is plumb the end of the wall and the entire wall ends up plumb for its length! That’s wicked fast!
Now lay your beam on top of the 2×4 top plate and nail them together as shown in the sectional view. Be sure to avoid nailing in the middle of the “stud bays” as that’s where plumbers and electricians will want to drill their holes. Keeping the nails in a common pattern will allow them to avoid the nails and will help them keep their bits sharp. They’ll love you for it! Once the beams are in place, you can start to straighten the walls as necessary. The cool thing is that if your beams are straight, you won’t have much work to do in order to get the walls straight. Bonus!
Install the interior walls and make sure that all of the walls are tied together by chiseling out a section of the beams (dado) the depth of the 2x interior top plate and then crossing your interior plates over the top of the dado. You can then nail down through the intersecting plate and voila, you are tied together and flush. See the overhead view here.
I recently received the following question from a visitor to my blog named Pat. I get this question and variations of it quite often. Here is the question:
I have a house built in 1911, the wood frame is 2×10 and 2×4 pine construction the wood is now so strong that a nail must have a pilot hole drilled first. Is it possible to add additions to this house using straw bale construction and tie the two together somehow? I live in Minnesota so I love the high R value of bale construction. I had also thought about completely encompassing the whole house and slowly removing the exterior of the existing house. The purpose would be to allow us to live here while we are building the additions. If you have done this how did or would you do it?
Here’s my answer
The idea of wrapping the house in bales is a common one and sounds like it would be a good idea in Pat’s climate. I have attached a video below that discusses three of the major areas of concern when working with wrapping an existing house with bales.
When attaching a straw bale addition to an existing house, the biggest concern is to make sure that the two structures are tied together well. The easiest way to do this is with expanded metal lath at each course. Lay a swath of lath on top of the bales and pin it to the top of the bale surface with dowels or landscape pins, the latter being easier. Then bend the lath up at a 90 degree angle and staple it to the framing of the existing house. The two structures are now tied together. Be sure to use lath spanning the face of the joint created between the bales and the existing structure before you plaster because the two building materials will move at different rates under different weather conditions.
Finally, make sure the face of the bales and the face of the existing walls are lined up properly “in plane” so that the finish plaster will not have a bump in the transition. The exact line up depends on the thickness of the plaster on the two substrates and the transition used. Just be aware that some thought will need to go into this before you even form the new foundation. Happy Baling!
My mother in law is currently having a barn built for her horses. I have been very impressed with the speed in which the structure has gone up. Three to four men have been working on the site for a bout a day and a half and the entire frame is up and most of the 2×6 interior wall boards are laid. This has lead me to think about the use of metal “kit” buildings with straw bales as the wall insulation.
Others have mentioned this to me in the past and I quite honestly did not see the advantages with the same sense of excitement that I do today. I can imagine having a house framed in two days and ready for bales! Wow, that would be exciting. I failed to mention that the barn currently under construction is no small affair. It is about 3000 SF so the day and half progress is very impressive. My mother in law said she had a lot of opportunities to fine tune the design to her liking, but not so many that she became overwhelmed. That is a great balance. If you have any experience with steel kit buildings and have some advice for how bales could marry this technology, please let us know!
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.
Consider the placement of the temporary braces. If the braces are placed on the inside of the frame, they will need to be removed when stacking the bales and the structure ends up free of lateral support. If the braces are placed on the exterior of the building, they need to be removed before the exterior mesh is installed. The exterior mesh holds the greatest amount of strength for the structure as it is fastened directly to the vertical framing as well as the top and bottom plates. The interior mesh is only attached to the plates and then sewn to the exterior mesh. Therefore, the mesh with the greatest strength has to be installed for the interior mesh to work at full capacity.
So how to deal with this dilemma? I install my braces on the outside of the frame during construction. The first pieces of mesh are placed on the interior faces of the wall after baling. They are placed as close to directly opposite of the temporary braces as possible. Once all of the interior slices of mesh have been fully installed, move to the exterior. I remove one brace at a time from the exterior and immediately install the mesh. I continue to install the mesh as I move down the wall until I get to the next brace. Only after all the mesh on the outside of the wall has been installed from the last brace do I remove the next brace. I continue down the wall in this fashion, never removing more braces than I can mesh up to. This gives me continued lateral support throughout the meshing process and limits the risk of the walls falling out of plumb.
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.
Although manufactured trusses are more expensive than stick frame roofs when it comes to materials, the labor savings are significant. In addition, if you have a flat ceiling in the home, you can install the ceiling joists and the rafters at the same time, again cutting back on labor. The advantage of stick frame roofs shows up when the roof gets more complex. For example, a roof with dormers or a roof with a lot of valleys and hips may be easier to frame as a stick built roof. In any home, there are a lot of choices and decisions to make. This is just one and something that needs to be decided during the design phase as the details of the framing plan will need to be completed for the plan review. In addition, the engineering of the home will be impacted by the roof design so any changes to the trusses or framing plan need to be run through the building department or other plan review offices.
I posted this exact message as a response to a question on the Podcast blog entry. For those of you who read it there, sorry for the duplication. After receiving a couple more questions about how to bale with exposed posts and beams I thought it was worth publishing this under its own heading.
Timber frame is a beautiful compliment to Straw Bale construction and it has been done several times in the past. The biggest thing to be aware of is that traditional timber frame is not cheap. A standard frame house may cost $6-$10 per square foot to frame while a timber frame home runs about $65 per square foot to frame. That is a major difference and the cost adds up quickly. It is possible to build exposed post and beam instead which is much more affordable and less of a specialty framing system. When doing this, a foundation must be poured for the bales out side of the posts or their load must be incorporated into the floor framing engineering.
Another consideration with running the framing on the inside of the bales is how to finish windows and doors and how the roof attaches to the building. Windows and doors are most easily handled by using bucks for their installation, boxes built for the windows that lay directly on the bales (or the floor for doors). By using bucks you can place your openings anywhere in the wall. In terms of roofing, it is always a good idea to have a large overhang (2′ or more) on bale walls. That is made a bit more difficult because the overhang has to cantilever from the inside face of the bales all the way out over them and that creates a weak spot for the roof frame. A simple truss design is a good idea (if post and beam) and the bent design for timber frame can also handle this. It is, however, important to be aware of this design issue before you complete the home design.
Another issue of concern is the plaster on the inside of the home. It will have a tendency to crack at every post if you are not careful. I like to use expanded metal lath (plaster lath) on the back side of the posts that extends out beyond them by about 6-8″ on either side of the post. This has to be installed before the bales. In addition, the bales need to be attached to the frame so more lath can be stapled to the back side of the post and then bent at 90 degrees and stapled into the top of a course of bales. Done at every course, this provides adequate attachment for the bales. The lath that was applied first allows the plaster to have a strong attachment point at the joint between the posts and the bales. A color matched caulk along that joint is a good idea too.