House building ideas

[Tom Sawyer]

In the Alternative Houses book they had a technique that I found interesting... stone walls built in slip forms two foot high at a time. You stack stone in the front of the form and pour concrete in the rear of the form.

I like the idea of reducing the steps of putting on finishing sheathing. No painting and just pressure watch ever decade or so.

One of the other labor/expense saving techniques the author promoted was to make the roof structure timber frame 4 foot on center with 2 x 6 tongue and groove on top of the timbers. It makes a nice looking ceiling below with no drywall step.

[Lloyd Danforth]

Love the new patch.  The Nearings used the slipform system for most of their buildings and describe it in 'Living The Good Life'  and 'Maple Sugar Book' ( I think).  Helps to have a lot of stones hanging around. Kinda labor intensive.  Results are all you said and beautiful.

[Russell Kanning]

Do I hear any bids?

Cathleen

I could not handle running your job. I am just a worker bee.
But I am sure we have a few guys than would be good at doing up the whole thing. They would just have to know everything about what sort of house you want in order to give you prices.
Where do you guys want to build?

[Russell Kanning]

I like the slipform idea ... and also the stone/cordwood type wall.
I think Lex is planning on going slipform with lots of rocks for his place.
I hate sheetrock. I wouldn't want to use it in my house. Give me some nice rocks/bricks/wood to look at.

[SpeedPhreak]

straw bale is NOT hay - hay will is a grassy material.  It will rot & your walls will fall apart.  Straw (from oats & such) is a woody material... though the end product is produced with the same equipment & look very much alike.  Straw is mixed w/sand & clay (& sometimes cement or lime) to construct cordwood, cob, & other natural building methods as well... both as a morter & as plaster.

I like most natural building meathods.  I chose strawbale as my favorite for ease, cost, asthetics, longevity, & insulation value.

I think cordwood is a great method... not for me, because I don't like the look - but it seems simple enough & makes great use of resources... not to mention its probably cheaper than straw bale (especially in NH i am sure).  Stone on the other hand I love the looks of & as a matter of fact plan on using it in my own personal projects.

Part of natural building is using a method that fits with & utilizes your immediate surroundings.  Cordwood would not be practicle in Arizona - stone/adobe/rammed earth/cob would all be better methods.  Part of it is also personal preference... which modern methods doesn't give you.

I never researched the slipform methods because it seems like a lot of work - though from what I have read it is a well received method.

[Crocuta]

Since you're a fan of straw, I was wondering if you'd seen the StrawJet technology being developed at Ashland.


http://www.greeninventor.org/strawjet.shtml

From a friend's website:

An interesting new use for straw as a building material has emerged recently in the form of a system called Strawjet, now being developed at Ashland School of Environmental Technology. The use of straw bale for non-toxic housing has tended to be tricky due to the problem of residual pesticides on on all non-organic agricultural products and the need for great care in preventing any possibility of mold or pest intrusion in the rendering encapsulating the straw bales. This new technology offers a new form of straw construction that may reduce these problems, though at present much more field experience is needed to determine its non-toxic housing potential.

Strawjet is based on the use of a special winding and binding mechanism which allows a harvester to produce a continuous thick cable of dense compressed straw fiber which is woven into composite panels and pultruded into beams with a cementous encapsulant. Individual cable cores can be replaced with pipe to serve as in-wall or in-beam utility conduits. Some very interesting architecture has been proposed for this technology, though not yet demonstrated. All in all, a promising technology but still in its very early stages of development.

Now what I think is really cool is that the combine that they built for the prototype harvests the grain and then makes the cables as it goes.

[SpeedPhreak]

That is interesting, I can't wait to see where it goes.

2 things I am worried about

1 - the encapsulant; 1 aspect about straw bale is that if you use a natural plaster on both sides is that it is breathable.  Which actually contributes positivley to indoor airquality & allows for any moisture to evaporate.  I wonder if what they use is breathable & if not if their are alternatives.

2 - thickness; straw bales can be up to 2ft thick.  this contributes greatly to the high R value.  but also allows for thick window sills & built in storage & such... plus rounded walls/corners & great sound insulation.

Still - strawjet may prove to be superior for the southwest where it rarely gets very cold.  I can also see using it on interior walls (where before I was going to use adobe or brick).  Although a properly built straw bale home is extrememly strong... maybe this will be stronger, especially in the long run.

[Tom Sawyer]

We will be making a decision soon regarding our home ownership plans. It is a struggle deciding what direction to go. We would have to hire a builder. I can't see anything cheaper than the modular home route, but we aren't sure that is what we want. We are more inclined to have a log home, but they are not cheaper than stick built. I've done a bunch of research, but will look into anything that we can find a builder to do for us.

The websites mentioned in this thread have really been teasers. Unfair! I want all of them.

Cathleen 

You might consider checking into Structural Insulated Panel construction.

This company in Keene designs and builds.
http://www.panelpros.com/

[Russell Kanning]

I like that idea for like the floors and ceiling of my rock/wood walled house.

dog has been pointing out those guys for a while .... didn't know we had some Keene guys doing them.

[Russell Kanning]

Fast floors with structural insulated panels: using floor panels supported by engineered-lumber girders cuts production time on SIP houses.

Source: The Journal of Light Construction

Publication Date: 04/01/2005

Author: LeRoy, Jim


COPYRIGHT 2005 Hanley-Wood, Inc.

My company is a distributor for Insulspan structural insulated panels in New England and New York. Insulspan's Michigan factory ships 8-by-24-foot panel blanks to us, and we cut and reassemble the raw panels into complete precut SIP packages for builders and commercial contractors. We also have several field crews who set panels on site, because many of our customers don't have crews with SIP training and experience.

We try to transmit the lessons that our crews learn in the field to outside framers who are working with our panels and packages. With explanations and tech support from our shop personnel, any competent stick-framing crew should be able to build with SIPs just about as well as our crews can--and similar support is available from other SIP suppliers in our region and around the country.

Eventually, I hope to see builders all over our region learning to use SIPs and handling them as easily as they handle components in stick construction. In principle, the two methods are similar--SIPs are just like big, wide, flat pieces of lumber. They come in standard sizes, and you can cut them up and connect them together to make whatever you want. You can use most of the same tools and fasteners, and most of the same techniques. It takes only one or two jobs for a skilled stick-framing crew to get comfortable using SIP methods.

For this article, I'm going to focus on floor systems. SIPs work particularly well for certain specialized floor applications. They make a quick and easy floor for a small room addition or bump-out, and a cost-effective and satisfactory floor over a large unheated space, such as a garage with rooms above it. The rural New Hampshire house shown in the photos for this story has SIP walls and roof, SIP floors above the garage and in a small sunroom, and conventionally framed floors over the basement and between the first and second stories.

SIPs are not ideal for floors between stories inside a house. The insulation isn't required at that interior location, and SIPs can be rather noisy underfoot--they easily transmit the sound of upstairs footfalls to spaces below. That's why we frame the floor systems for our SIP houses with conventional methods, using engineered wood beams, wood I-joists, and OSB floor sheathing.

However, to shorten the site time for our road crews, we've started panelizing a lot of our floor systems in the shop, and setting the large floor sections on site with our crane. That helps us make the most of the on-site efficiency of SIP wall and roof construction; when we don't prebuild, framing floors on site is the one part of the job that takes us as long as it would take anyone else.

So, on these pages I'll cover SIP floor applications first; then I'll describe the way we panelize wood I-joist floor systems and the various methods of detailing SIP walls to support the loads imposed by stick-framed floors.

Insulated Floor for a Small Room

The floor of a small bump-out or room addition is one of the quickest and simplest uses of SIP technology (see Figure 1, facing page). SIP blanks come 8 feet wide by 24 feet long, so we were able to cut this sunroom floor from a single panel. The floor panel bears on the foundation wall on three sides. Where it joins the floor frame of the main house, it attaches to an LVL ledger beam.

[FIGURE 1 OMITTED]

It's common practice for us to sleeve a beam or structural spline into a space routed out of the panel's foam. In this example, we placed the structural member first, and then slipped the panel edge over it. To do that, we had to remember to leave space for the panel's OSB skin between the LVL beam and the member below it. We typically use a 1/2-inch plywood shim to space the beam away from other framing, leaving just a tiny bit of extra room to slide in the 7/16-inch or 15/32-inch OSB. In this case, the panel was a tight fit on the beam, so the crew had to use come-alongs to pull it snugly into position.

The floor panel was 10 inches deep, for about an R-40 insulation value, but it wouldn't have to be that deep to make the 8-foot span. The rule of thumb for typical floor loads goes like this:

* 6-inch panels will span about 8 feet

* 8-inch panels will span 10 feet

* 10-inch panels will span 12 feet

These spans are achieved without structural splines. If you use 4-footwide lengths of panel with LVL members embedded in the joints, it's technically possible to achieve clear spans of as long as 24 feet. But when a design calls for long spans, we prefer to support panels from below with engineered beams, as we did for the floor over this house's garage (Figure 2). That's a simpler assembly to set up, and it's also more convenient to air-seal at the seams.

[FIGURE 2 OMITTED]

We lift the floor panels into place with the crane (Figure 3). Panel builders often lift panels using big steel hooks that they drive through the panel skin. We used to do that, but it's frowned upon these days because of the surface damage it does to the panel. So now we use a steel lifting plate, which we screw directly to the panel. The plate accepts 16 screws, enough for a strong attachment.

[FIGURE 3 OMITTED]

Once the floor is in place, its routed edge will be filled with an LVL rim joist. The LVL's structural capabilities aren't really needed in this location, but we use LVL because it's stable. Ordinary lumber would shrink away from the panel, creating gaps and potential air leaks.

Insulated Floor Over a Garage

The classic SIP floor application is as an insulated lid for an unheated garage. This location is notoriously hard to insulate and air-seal in stick construction; with 12-inch SIPs, however, you can have a true R-48 floor with no thermal bypasses and virtually no leaks, after just a morning's work.

Official R-values, by the way, are measured under laboratory conditions at an ambient temperature of 75[degrees]E One good thing about expanded polystyrene (EPS), the core material in SIPs, is that its R-value increases as the temperature decreases. At 7S[degrees]F, EPS has an insulating value of R-3.8S per inch, but at 25[degrees]F, it's R-4.3S per inch. That's why I tell people the R-value of a 10-inch panel is "about R-40" and that of a 12-inch panel is "about R-48." At 75[degrees]F, it's really a little less, and at 25[degrees]F it's a little more--but who needs insulation at 75[degrees]F, anyway?

With fiberglass, it's the opposite: The colder it gets, the less actual insulating value fiberglass has. And the effect continues: When it's below zero outside, fiberglass loses even more of its rated value, whereas EPS gains value. Keep in mind that the floor over a garage in a cold state like New Hampshire is one of those places where effective R-value really matters. At -5[degrees]F with the wind blowing, your feet appreciate insulation that performs better when the weather gets colder.

Air-sealing matters, too, of course. The body of a structural insulated panel is airtight by nature, but joints and seams need attention. We seal every joint in the house with construction adhesive, expanding foam, or adhesive membrane tape. For a garage floor like this, we apply construction adhesive to the foundation sills before placing the panels; then, after all the structural connections are made, we inject expanding foam into the panel-to-panel joints.

We make the structural connection between adjoining floor panels by sliding splines into prerouted edge spaces (Figure 4) and stitching the panels together with staples or 8d nails. Floor perimeters, as usual, get stuffed with LVLs (another spot where we apply construction adhesive). We fasten the panels down at the sills and at supporting beams with long, hardened-epoxy-coated screws (Trufast Corp., 800/443-9602, www.trufast.com).

[FIGURE 4 OMITTED]

One drawback to a SIP floor is that it has no framing voids where you can run wiring or mechanicals. In a garage, code officials may allow you to fasten Romex cable directly to the ceiling. If they don't, you may have to furr down the ceiling or build out a chase for the wires.

In the house we're showing here, the transition got a little complicated where the floor above the garage met the first-floor frame of the main house (Figure 5, facing page). A 6-inch panel provided a convenient stepped-down floor for the home's entryway, but there was some fussy framing involved in joining the different thicknesses of panel and connecting them to the conventionally framed floor.

[FIGURE 5 OMITTED]

Panelizing Wood I-Joist Floors Whether panelizing a wood floor or framing it on site, you have to consider the wall structure that will hold up the floor (Figure 6). The floors for a SIP building can sit on top of the walls, just as they do in conventional platform framing. But then you lose the SIP wall's insulating value at the floor perimeter. So we like to hang the floor systems inside the wall, using top-nailing joist hangers. (Some designers use a system like balloon framing, with a ledger board face-attached to the panel's interior skin, but that brings up some tricky structural issues we prefer to avoid.)

[FIGURE 6 OMITTED]

Point loads. SIP walls can carry the distributed load of a "hung floor" even better than a typical stick wall. But for point loads, like the end of a floor's midspan girder, SIPs need structural reinforcement. Where a girder meets a SIP wall, we usually bury a post inside the wall to catch the beam. If there's a window or door opening in the wall where the post would fall, we sleeve an LVL header into the panel above the opening; posts at either side support the header. A beam can either sit on top of the header or attach to the face of it with a beam hanger.

We rely on load tables from the engineered-wood suppliers and hanger manufacturers when we spec this type of connection.

Wood I-Joist Floor Panels

Panelizing the floors as well as the walls has several advantages. First of all, it lets us take full advantage of the crane we bring to the site. I'll ask my crews to manhandle wall sections as big as 8 by 10 feet without equipment, but we need a crane to set larger wall assemblies, engineered beams, and roof panels. If we use the crane for floors, too, we can maximize the value of our investment in equipment.

Prebuilding also lets us compress the schedule by accomplishing two phases at the same time: Our crews can be at our shop framing the floors while the foundation contractor is still on site forming and pouring the basement. Saving days from the site schedule has particular benefits for us: My crews live near our Keene, N.H., shop, but they often have to travel to jobs around the region, staying overnight in motels. Framing the floors in the shop lets them have more time at home.

When we get a set of plans to panelize, a designer here in our shop analyzes the floor loads to determine where point loads will need to be supported within panels, and where wall openings may need headers. If we're planning to panelize the floors, the designer breaks up floor systems into 8-foot sections (the section width is limited by the length of the floor sheathing). The crew assembles the floor sections in our shop (Figure 7). On site, they use the crane to "fly" the pieces into place (Figure 8, facing page).

[FIGURES 7-8 OMITTED]

The total time it takes to frame the floor probably isn't much different with this system than it would be with on-site framing. Whether we work in the shop or in the field, we still have to put all the pieces together. But building the floors in the shop is safer: There's less fatigue; there's less time when the crew is exposed to the risk of falling; and help is nearby if there's an accident. It's also easier to keep tools and materials organized and available, and if there's any confusion about the plans, the designers are right in the building.

That doesn't mean things always go perfectly. With panelizing, you have to be careful to double-check everything. It's easy to make a mistake in dimensions or load paths when you're building the house in pieces, and we've made a few. But with each house we panelize, we get a little better, and we're finding that the added productivity--along with the convenience we can offer our customers--makes that learning curve worth the climb.

Jim LeRoy owns and operates Panel Pros, Inc., in Keene, N.H.    


COPYRIGHT 2005 Hanley-Wood, Inc.

[yamnuska]

Good info on building with mud, I was very surprised with how warm it was up in the himilaya with these mud huts, warm enough in winter to grow plants indoors without other heat sources.

    http://www.secmol.org/solarenergy/

[bailey228]

In reference to wood vs, straw for building in NH, I am not convinced that straw will not rot in our high humidity climate. Also like russell said, it is not local. I searched and found very few farms selling straw. I wanted to do strawbale, I really did want to work, but there is a reason why there is not a history of strawbale here like there is in drier climates after the invention of the baler.

Wood/logs are not expensive. I've already priced out enough logs for a 2300 sq ft house. It would be $1,500 straight from the logger. (support the local man while getting a cheaper product) The logs come green. You can either let them dry then build, or you can use the rebar method which does not require the logs to be dried. Wood in NH is cheap, ecologically friendly, and this region's tradition. The 200 year old houses still standing today are built of wood on stone foundations. Speaking of stone, I also priced that out. Stone for a rubble trench foundation for same size house was $2000 delivered. (plus another few hundred for the gravel, $300 if I remember correctly) This is compared to $7000 for the same amount of concrete.

I've looked into every natural building method there is, and I am convinced that wood/stone is the cheapest and best way to go for this area.

[MaineShark]

Just remember that "cost" should include cost of ownership, in addition to the actual construction cost.  Some of these methods are very energy-efficient, but some are not, and the heat demands in this area are no joke...

Joe

[SpeedPhreak]

looks like you have done your homework bailey.

I dont think I know a single person that doesnt like the look of a log home & if its with in your means & thats what you want then go for it.  same goes for anyone with any building method - thats what "freedom" is all about right?

from a tech standpoint - i am not an expert on strawbale (yet) & don't know how it would do in NH.  I am pretty sure it would be fine because they use SB in Oregon & Ireland (as well as all the other methods in both locations).  With proper roof protection, wall covering, & footer/foundation moisture won't be any more a problem than other construction methods.  Rembemer the walls are breathable with the proper materials & techniques.

from an eco standpoint using local material is a key principal & if straw would have to be trucked in - it turns into a luxury.

If/when I move to NH I will keep SB in my top 3 - for 2 main reasons - ease of construction & insulative value.  But a log structure ($1500 for the material is quite attractive) would not be out of the question either.

[bailey228]

 I wasn't trying to say no one should build one, of course I'm all for personal choice/freedom, just saying, that's the conclusion *I* came to. Breathable walls are a must for strawbale, but straw starts to rot at 20% moisture, and the humidity levels here are almost always high. (right now my meter says 67% on a sunny day) I'd see the moisture going in, but the humidity would never drop low enough to let the moisture come back out. My question would be, how old is the oldest strawbale house in oregon or Ireland? Are they lasting longer than 10 years? 20 years? 100 years?? I know there are a few strawbale houses in NH, but none of them are more than a few years old. If you do decide to build a strawbale house in NH, I'd love to see it in 10 years or so, and see if it's held up. I don't mind being proven wrong.

When I was looking, the nearest source of bales was NY. My logs are coming from 20 min away.