We have previously discussed a number of low cost, do-it-yourself trusses and roof systems. Use the search engine above with keywords such as ‘truss’ or ‘roof’ to find older blog posts.
Today’s post is about a special type of truss called loft trusses. Also called attic trusses, room-in-attic trusses and attic storage trusses, they create cost efficient extra space in the attic that can be used as a loft or for storage. This method is one of the most practical ways to gain space, often because attics are not fully utilized. It’s almost free space. Many times attic trusses have steeper roofs to create additional space, and can be used in place of conventional trusses. You don’t have to build the loft right away. The loft can be built at a later date when you can afford to finish it. Standard truss spacing is usually 24” apart. Truss manufacturers typically give free quotes and engineer the truss to meet local codes.
Trusses are one of the best options for building roofs. They are popular because they are very strong, efficient and relatively lightweight. They also create ample space for roof insulation. Trusses can be built before the walls are finished, and installed quickly. Trusses are made of multiple short pieces of light-weight wood. Because trusses span longer distances, fewer center walls or supports are needed. If you live where building codes are enforced, then using trusses will make code compliance much easier.
This may be a silly question but if you build your roof structure then build your earthbag walls, how do you effectively tamp the bags with the structure above you? It would seem you couldn’t stand on the wall to tamp the bags correctly. I’ve thought of building the roof first to protect the bags and site but stopped there thinking there was no way to build the walls correctly. Thanks guys!
In this example, you embed the nailers as you build the dome and then add the plaster, rafters and roofing later.
But there are various ways to build the roof first. The most common way is building a post and beam frame. We’ve discussed this before: http://earthbagbuilding.wordpress.com/2011/11/30/earthbag-shield/
hmmm. Sorry for the confusing question. I wasn’t referring to domes. I was wondering how to build a roof structure(post and beam) first and then build
vertical earth bag walls under it. It just seems it would be difficult to tamp the bags as you got higher. I guess I’m just missing something here haha. Better get some more coffee.
Did you read this blog post? http://earthbagbuilding.wordpress.com/2011/11/30/earthbag-shield/
Options:
– build the post and beam frame, but add the roof later (example: use tarps for shade)
– build the post and beam frame, build most of the roof except for the bottom part so you have room to work
– make the post and beam frame larger than the earthbag house so you have space in the attic to work
We want to build a roof first and then the earthbag home. Do you think it’s easier to build a post and beam structure and use earthbag in-fill? We are thinking about building a roundhouse within the posts that will hold up the roof, keeping the walls separate from the posts. We are now considering earthbag in-fill between the posts for a rectangular shape home if it would be wiser. I assume we could just dig the rubble trench foundation between the posts after they are set.
We bought some of your roundhouse plans, really like the idea of a roundhouse but want to take the most efficient route after building a roof first.
Working under the protection of a roof is especially practical in rainy, and very hot and cold climates. This method is highly recommended if you live in a climate like this. In relation to post and beam, it makes no difference whether the earthbag walls are straight or round. For instance, you could set 8 posts with beams in a square with trusses on top. The earthbag walls could go between, outside, inside the posts or in a circle. All are possible. The bags in this case would not be supporting the roof, so it doesn’t matter what configuration they’re in. So choose your favorite shape.
And make sure the post footings are deeper than the rubble trench so they are strong. I would dig both at the same time.
Thanks for the response. I think a roundhouse inside the posts would provide a great opportunity for a wrap-around porch. A few earthbag benches placed next to the wall..
Now I have loft trusses to think about as well. :)
That would create a nice overhang as large as you want. The best size depends on your climate. In cold climates you want some solar gain through the windows in winter. But hot climates you don’t necessarily need direct solar gain.