THE MUD HOME
  • Home
  • Building
    • Earthbag
    • Living Roofs
    • Gravel Foundations
    • Off-grid how to >
      • Off-Grid Prep Course
    • Earth Plaster
    • Mud as Mortar
    • Wattle and Daub
    • Lime; Hydrated, Hydraulic, and Putty
    • Mud Building Blog
  • Books
    • Dirt Witch
    • Mud Ball
    • Mud Mountain The Book
    • An Earthbag House in 7 Days?
  • About
    • Contact
  • Learn Mud
    • Courses
    • Mud Building PDF Package
    • Consultancy
    • Mud Home Facebook Group
    • Other Projects
  • Earth Whispering
    • The Earth Whispers Podcast
    • MUD MOUNTAIN

Considering going off-Grid?

Sign up for the mini course

The Beginners' Guide to Roofs for Earthbag

27/3/2018

6 Comments

 
The type of roof you choose for an earthbag house is important. No matter whether you construct a circular house or a rectangular one, you want to take into account your roof before you build (or be prepared to alter your roof style at the end).

I won’t deny it. When it came to my earthbag roof, as is so often the case with me, I skidded to success by the seat of my pants. It was sheer luck I chose the right type.

Roofing structures exert a lot of pressure onto earthbag walls. This is fine if the pressure is in the right direction because earthbag walls are strong. What you want is the pressure exerted downwards. What you don’t want is it pushing outwards.
PictureThe easiest and safest roof for a beginner is a flat one with horizontal joists.



The safest roof type for earthbag
If you are a beginner, the safest, most foolproof roof to stick on your earthbag house is a flat or skillion (pitched) roof, utilising horizontal joists running the length of the building. The joists act as a type of grid that pulls the structure together and prevents the walls falling outwards. What’s more, if you’ve built a smallish round house, you won’t even need a bond beam! You could top the joists with a number of materials: Corrugated iron, ply/strand board with a membrane. Any weight on the roof will be distributed by the joists and easily supported by the earthbag walls. The pressure exerted by such a roof is downward.
Picture
The joists form a grid which locks the entire structure together
Angled roofs
Steep A-frame roofs will probably need trusses and a bond beam. The trusses pull the roof structure back inwards, so your earthbag walls are not bearing the brunt of the outward pressure.
Picture
Roof trusses by Johann Jaritz - Self-photographed, CC BY-SA 3.0, httpscommons.wikimedia.orgwindex.phpcurid=16356071
Here’s nice example of an open gable roof on an earthbag house without trusses, with a wooden bond beam.
http://kathmandupost.ekantipur.com/printedition/news/2017-11-05/earthbag-building-techniques-may-be-the-best-way-to-ensure-disaster-resistant-homes-in-rural-nepal.html

The Independent Roof
Another safe roofing option is to create a roof that stands independently of the earthbag structure, as Gautam and Kim did with theirs in India. You might still want to run a few joists across the top of your earthbag house here to lock it together though.
Picture
So you want a reciprocal roof?
I don’t blame you, reciprocal roofs are beautiful. But…depending on how they are designed, reciprocal roofs can exert outward pressure on your walls, especially if you're using hefty posts. This doesn’t mean you can never put a reciprocal roof on a round earthbag house, however you need to be (or have access to) a reasonably decent carpenter to do it. If you are adding such a roof to a roundhouse, you will need a decent bond beam, and possibly even some buttresses (depending on the size of your roundhouse). Mustafa the carpenter made this gorgeous one in our workshop in Olympos, but there was some very precise measuring and angling of the beams to ensure the roof wasn’t pushing the walls out.
Picture
Mustafa's alternative reciprocal roof.
The link below shows another example of an alternative reciprocal roof on an earthbag house. Notice how this team combined two styles here. While the main structure is reciprocal, a web of rafters has been inserted into each facet of the roof. Those rafters then form the all-important grid through the top of the earthbag wall which locks the whole structure together.
http://mylittlehomestead.com/ep12-undergound-earth-bag-construction-reciprocal-roof-facia-frame-complete.html

Why you don’t want a compression roof
Compression roofs are typically used for yurts. The design of a compression roof means the strength of the roof structure is derived from the compression between an outer ring or wall, and an inner ring. Such a roof is exerting a lot of outward pressure on your earthbag walls.

If you know what you’re doing, there are of course a whole gamut of other wacky and exciting options for earthbag house roofs, and you'll be able to customize many to work for earthbag. But
presumably, if you know all about roof construction, you're not reading this post.
Picture
Compression roof on a yurt. Not a good idea for earthbag.
You have read this free article thanks to The Mud Home Sustainers and all those supporting The Mud Home, be it with contributions, positive and constructive feedback, or by sharing. If you’d like to join our huddle of Mud Homers, get help with your build, and enjoy a bunch of other perks, head over to the Patreon page.
6 Comments

    Many thanks to the Mud Sustainers supporting this site!

    List of Sustainers
    Picture
    Do you find The Mud Home valuable? Please consider supporting the blog on Patreon. For as little as $2 a month (not even a coffee where I'm from), you can join the club.
    BENEFITS FOR PATRONS INCLUDE:
    Email priority, private Facebook group, review copies of my books, sneak previews of courses and books, Q and As, priority for courses and more.

    Author

    Atulya K Bingham
    Natural builder and author of Mud Ball.


    Picture
    "Beautifully written and inspiring." The Owner Builder Magazine

    FREE!

    Picture
    If you want the step by step guide of how I built my house, sign up for the PDF.
    WHY NOT? IT'S FREE!

    Categories

    All
    Adobe
    Building Codes
    Building With Wood
    Cob
    Composting Toilets
    Earthbag
    Earthbag Mistakes
    Earth Plaster
    Hobbit House
    House Renovation
    Insulating Plaster
    Laying Earthbags Faster
    Limecrete Floor
    Lime Plaster Issues
    Natural Floors
    Natural Roof
    Off Grid
    Permaculture
    Roofing Options
    Stone Houses
    Straw Bale
    Sustainable Building
    Using Lime
    Wattle And Daub
    Yurt

    RSS Feed

    Picture
    Join the free Mud Home earth plaster mini course.

    Picture
    All the Mud Home How-to posts have been compiled into a PDF package with 75 articles and over 200 photos. You can still buy it now, and enjoy lifetime access to all the updates.
    PDF Contents

    My latest book is now out!
    Picture
    “Entranced! Be inspired by one who’s lived and breathed dirt.”
    Kim Fraser, Get Rugged
Disclaimer: All the content in The Mud Home website is provided for informational purposes only. The author undertakes no responsibility for any person or entity who chooses to use the information on this website. It is not intended to be a standard and should not substitute for the exercise of good engineering judgment by engineers. It is the user’s obligation to make sure that he/she uses the appropriate practices and consults the appropriate experts when building.

EARTHBAG BUILDING PDF
EARTH PLASTER GUIDE
BOOKS
MUD MOUNTAIN
NEWSLETTER
About Atulya
Privacy Policy

SUPPORT

Picture
Picture
The Mud Home takes many hours a week to run, and costs a lot to sustain. If you find this site useful or inspiring, please consider supporting it so that it can continue.
Picture

Many thanks to all those who've already become Mud Sustainers.

The Mud Home  Copyright © 2013  Atulya Kerry Bingham
  • Home
  • Building
    • Earthbag
    • Living Roofs
    • Gravel Foundations
    • Off-grid how to >
      • Off-Grid Prep Course
    • Earth Plaster
    • Mud as Mortar
    • Wattle and Daub
    • Lime; Hydrated, Hydraulic, and Putty
    • Mud Building Blog
  • Books
    • Dirt Witch
    • Mud Ball
    • Mud Mountain The Book
    • An Earthbag House in 7 Days?
  • About
    • Contact
  • Learn Mud
    • Courses
    • Mud Building PDF Package
    • Consultancy
    • Mud Home Facebook Group
    • Other Projects
  • Earth Whispering
    • The Earth Whispers Podcast
    • MUD MOUNTAIN