No edit summary |
No edit summary |
||
| Line 1: | Line 1: | ||
'''Coming Soon!''' In this page we will describe to you how to build a basic understanding of reciprocal roof construction with step by step instructions. | '''Coming Soon!''' In this page we will describe to you how to build a basic understanding of reciprocal roof construction with step by step instructions. | ||
<br /><br /><br /> | <br /><br /><br /> | ||
A reciprocal frame is a class of self-supporting structure made of three or more beams and which requires no center support to create roofs, bridges or similar structures. As quoted from [http://en.wikipedia.org/wiki/Reciprocal_frame]<br /><br /> | |||
This page is intended to show the basic How-To's of installing a reciprocal roof on a structure. <br /><br />The reciprocal roof lends itself to round walled structures. This structure is a hexagon, although, an octagon, decagon, or vertex-less/circular one would make installation easier. The reason being that the reciprocal roof pitch is determined by the ''x'' distance from the top plate to the tangent of the center ring where the rafters lay reciprocating over each other. If the ''x'' distance changes, ex: in a square with four corners the ''x'' distance from the center point of the square to the edges of the square box are not equal. It is a greater distance from the center to the corner than to the center of a face/side of the square. Therefore, the pitch of the roof will be shallower at the corners and steeper at the faces. In theory, the non sided circle is the best way to achieve an even pitch around the whole structure making a conical roof. | This page is intended to show the basic How-To's of installing a reciprocal roof on a structure. <br /><br />The reciprocal roof lends itself to round walled structures. This structure is a hexagon, although, an octagon, decagon, or vertex-less/circular one would make installation easier. The reason being that the reciprocal roof pitch is determined by the ''x'' distance from the top plate to the tangent of the center ring where the rafters lay reciprocating over each other. If the ''x'' distance changes, ex: in a square with four corners the ''x'' distance from the center point of the square to the edges of the square box are not equal. It is a greater distance from the center to the corner than to the center of a face/side of the square. Therefore, the pitch of the roof will be shallower at the corners and steeper at the faces. In theory, the non sided circle is the best way to achieve an even pitch around the whole structure making a conical roof. | ||
<br />In this hexagonal structure built in a series of community workshops the roof pitch does vary slightly from vertex to face; but this can be mitigated slightly by placing the rafters a distance away from the vertices. It is good building practice to place the rafters a distance away from the vertices for strength in holding wood in attaching the rafter to the top plate or beam. | <br />In this hexagonal structure built in a series of community workshops the roof pitch does vary slightly from vertex to face; but this can be mitigated slightly by placing the rafters a distance away from the vertices. It is good building practice to place the rafters a distance away from the vertices for strength in holding wood in attaching the rafter to the top plate or beam. | ||
| Line 13: | Line 14: | ||
|File:Reciprocal Roof Construction 1 Finished walls with no roof.jpg |Hexagon Structure Awaiting a Reciprocal Roof |1 |Here we have a Hexagonal structure ready for a roof. This structure is a basic round pole gazebo style made from Hawaiian Iron wood (aka: Australian Pine, Whistling Pine, Horsetail Beefwood). The top plates are all about the same length and diameter each lapped over the previous in a reciprocal fashion. The idea being to equalize all joints in strength since the weight of the reciprocal roof presses down and out at top plates. In other words, the roof wants to make the hexagonal top plates break the circle. | |File:Reciprocal Roof Construction 1 Finished walls with no roof.jpg |Hexagon Structure Awaiting a Reciprocal Roof |1 |Here we have a Hexagonal structure ready for a roof. This structure is a basic round pole gazebo style made from Hawaiian Iron wood (aka: Australian Pine, Whistling Pine, Horsetail Beefwood). The top plates are all about the same length and diameter each lapped over the previous in a reciprocal fashion. The idea being to equalize all joints in strength since the weight of the reciprocal roof presses down and out at top plates. In other words, the roof wants to make the hexagonal top plates break the circle. | ||
|File:Reciprocal Roof Construction 2 Rafter poles staged and ready.jpg |All the rafters awaiting installation |2 |Here we have all the rafters awaiting installation. The rafters are all cut quite longer than required for the roof. Working with round poles that are not all together straight and have varying taper it is a good idea to leave all your members long so that they can be twisted and positioned right where each piece fits best. | |File:Reciprocal Roof Construction 2 Rafter poles staged and ready.jpg |All the rafters awaiting installation |2 |Here we have all the rafters awaiting installation. The rafters are all cut quite longer than required for the roof. Working with round poles that are not all together straight and have varying taper it is a good idea to leave all your members long so that they can be twisted and positioned right where each piece fits best. | ||
|File:Reciprocal Roof Construction 3 Added ties and finding center with string.jpg| | |File:Reciprocal Roof Construction 3 Added ties and finding center with string.jpg|Finding the center of a hexagon |3|In addition to the reciprocal top plates mentioned in step 1, three additional members were added atop the hexagon of top plates for more strength. The added members extend from the middle of the top plates' span cross to the center of the opposing span, making the view from above or below a triangle inside of a hexagon. This step is not required for all applications. It was chosen here because the walls in this particular structure are simple and not reinforced. A circular cob or earthbag structure would likely not require such extra tension support. The three members were also installed simply to make the installation of the rafters easier by serving as scaffolding to stand on. <br /> String lines across the vertices help us find center so we an determine the position of the charlie stick. | ||
|File:Reciprocal Roof Construction 4 Attaching the Charlie Stick.jpg |Hexagon Structure Awaiting a Reciprocal Roof |4 |Whatever you do in step 4. | |File:Reciprocal Roof Construction 4 Attaching the Charlie Stick.jpg |Hexagon Structure Awaiting a Reciprocal Roof |4 |Whatever you do in step 4. | ||
|File:Reciprocal Roof Construction 5 Close up of Square Lashing.jpg |Hexagon Structure Awaiting a Reciprocal Roof |5 |Whatever you do in step 5. | |File:Reciprocal Roof Construction 5 Close up of Square Lashing.jpg |Hexagon Structure Awaiting a Reciprocal Roof |5 |Whatever you do in step 5. | ||
Revision as of 21:11, 13 May 2014
Coming Soon! In this page we will describe to you how to build a basic understanding of reciprocal roof construction with step by step instructions.
A reciprocal frame is a class of self-supporting structure made of three or more beams and which requires no center support to create roofs, bridges or similar structures. As quoted from [1]
This page is intended to show the basic How-To's of installing a reciprocal roof on a structure.
The reciprocal roof lends itself to round walled structures. This structure is a hexagon, although, an octagon, decagon, or vertex-less/circular one would make installation easier. The reason being that the reciprocal roof pitch is determined by the x distance from the top plate to the tangent of the center ring where the rafters lay reciprocating over each other. If the x distance changes, ex: in a square with four corners the x distance from the center point of the square to the edges of the square box are not equal. It is a greater distance from the center to the corner than to the center of a face/side of the square. Therefore, the pitch of the roof will be shallower at the corners and steeper at the faces. In theory, the non sided circle is the best way to achieve an even pitch around the whole structure making a conical roof.
In this hexagonal structure built in a series of community workshops the roof pitch does vary slightly from vertex to face; but this can be mitigated slightly by placing the rafters a distance away from the vertices. It is good building practice to place the rafters a distance away from the vertices for strength in holding wood in attaching the rafter to the top plate or beam.
Enjoy this How-To for educational purposes, if this page does not help or if you are looking for more, here is another reciprocal roof how to with blog The year of Mud Reciprocal Roof Blog, enjoy.