Trussed Rafter Roof | What Is Trussed Rafter Roof?
Trussed rafter roofs, also known as roof trusses, provide a structural framework to support roof fabric, ceilings, or building floors in both domestic and commercial structures.
The point of adding a Belfast truss in Figure 6.10 is to show the main trees. The truss was put together, and the thin truss was pushed to the side by a thin boarding – very effective.
So it is not surprising to know that the idea of using wooden plates on each side of the node is the best and cheapest way to make trusses. If cheaper plywood is available, it can often be used with less waste; Obviously, plywood can be very thin and therefore reduce the bulk of the node points.
Pattern nailing is required – thin nails and lots of them and long enough to penetrate
Mostly through the opposite side of the tree. Of course, we’re only talking about it
Single layers of wood, not multiple layers used in TRADA trusses.
The processes are simple but strenuous, there is no way to make any big savings in the tree before the arrival of a pressure-grade tree and the difference in the performance of each node.
Installation Process Of Trussed rafter roofs:
Everything had to be over-engineered to give it extra security. This changed rapidly with the advent of both pressure stratification and the invention of the gang nailing plate. Pressure grading allowed engineers to treat wood in the same way that metals were treated; The performance of the tree can now be predicted with some accuracy.
This means smaller parts of the tree can be used. Gang nail plate has many advantages over nails and bolts as a method of joining:
1. In any one assembly only two pieces of metal are involved
2. There are no holes to drill
3. There is nothing to tighten
4.No manual labor – other than placing the components – is involved in manufacturing
Joints
5. The results of using the panels are highly predictable
6. There are no notches for cutting wood – only square or slices
7. The wood is cut in a jig and fastened in a jig
8. Does not include any adhesives, heat, or other components.
Figure 6.12 is a diagram of a single gang nail plate and Figure 6.13 is a photograph of a node On the roof truss. The plates are pressed on each side simultaneously using a hydraulic press. The result is little spikes on the plate
all penetrate at the same time, under even pressure. Different sizes of plates are available to suit the conditions which will prevail at any node in a structure.
The manufacturers of the plates provide a complete service to the industry. They don’t
make trusses themselves but they supply all the machinery necessary:
The jigs in which to cut as well as set out the timbers and the joining plates
The hydraulic presses
Computer software to design the trusses
The plates.
What is very different about these trusses is the fact that they don’t support purlins which
support common rafters etc. These trusses support a section of roof that extends
halfway to the next truss on either side. So we are putting up a whole series of lightweight
trusses and the roof covering is laid immediately on these.
Figure 6.14 is a photograph of some newly erected trussed rafters on a two-story house.
They are spaced out at 600 centers and are set on and fixed to a wall plate bedded and
fastened down to the inner leaf at the wall head.
Figure 6.15 shows the wall plate lying down and the two straps holding it can be seen at the top of the plate. In Figure 6.14 you can see the ends of these strips running down the far wall. They stone the blockwork.
Figure 6.16 shows the detail of the roof suites. The ends of the trussed rafters sit
The Wallplate and fastener can be seen hitting the wall plate and the trussed rafter – each trussed rafter.
Attached to the ends of the trussed rafters is a longboard eaves fascia board. It is simply nailed to the ends of the projecting rafters and finishes off that vertical face. Attached to it is support for guttering. Figure 6.17 is a photograph taken through the center of the trussed rafters.
Note that the ties of the trussed rafters are two-piece and joined with the gang nail
Saucer. We covered a lot of construction with these four photographs and perhaps raised many questions in the mind of the reader.
Below we will try to answer some of these questions. Before that, there is one important thing to know about trussed rafters. They could be The wood is made of different shapes using different sizes depending on the loads Has been charged.
The shape and design of the trussed rafters in the photographs is known as the Fink truss
And the incentive of internal strutting is easily recognized because of the W shape.
Figure 6.18 illustrates the Fink layout and some other common systems. There are more
Including the mansard truss and attic truss shown in Figure 6.19. In the word panel
The relationship of these truss shapes indicates the rafter’s unsupported length in each.
First, the Fink truss has four panels – each rafter is supported by struts in the center of its length, dividing each rafter into two, so four plates. The book, which is really intended for the Timber Engineer but is worth mentioning, is Ozelton and Byrd’s Timber Designer’s Manual, now in its third edition and published by Blackwell Publishing.
There is a wealth of information on design calculations and methods that are not available from other sources. After the construction of the roof with the construction of trussed rafters, it is necessary to build stone walls on the tie level and rafter level.
This is done in the same way that the floors are tied to the stone walls, but nowhere in my journey have I been able to find an example of a photograph handle
The metal strap shows the correct style but the blockwork is hacked to fit it and it is nailed to a thin strip of wood and the top of the tie. A hacked hole in the blockwork violates the integrity of the wall, which is no longer fire-resistant.
Nail grips should be challenged for a strap into thin wood. There are no noggings between the ties and no solid packing or wedges between the last tie and the wall.
Figure 6.21 shows the correct style of the bar, this time attached to a fairly heavy horizontal bearer, fixed across the face of the trussed rafters’ struts
Rafters. Better so far, but no wall insight; This is obviously a case of getting a tie now and we will build a wall for it later.
That is correct, but there must be serious suspicion that at this particular site, the stone is even closer. The scope of the photograph in Figure 6.21 is deliberately placed wide enough to show one or two other points.
At the very bottom left side of this roof is possible to see the diagonally opposite corner
Waiting for the stone with another bar. Also, notice how small the gang nail is
The plates move from the center to the top of the struts line and move to the right
Photograph.
These struts are compressed and therefore should be suppressed in position only when upright. They are now installed and securely attached to the wall plate and attached to the stone wall beneath it.
The horizontal and diagonal bracing can be seen in Figure 6.21 and we have already criticized the wall restraint systems. The next part of the preamble is done
For the formation of edges. An edge ladder is made, so-called from its appearance because it is used for climbing.
Each edge has a ladder and Figure 6.22 is a good example. It is made of a wood-framed house but the rest of the roof is not made of trussed rafters; It uses three trussed purlins.
Figure 6.23 contains diagrams of the edge ladder and how it is fitted. Note that the full preset version has a finish to the edge and bottom. These plates are frequently painted up to the undercoat stage and many are made with PVC verge boards and soffit plates.
Drawings illustrate terminology. These are traditionally made of stick-built roofs
The trees – and a few more – were all cut and fitted separately from the scaffold.
The edge ladder has four components:
(1) One side of the ladder is the edge panel.
(2) The other side of the ladder is a simple wooden tray but mostly 9 or 12 plywood lengths.
(3) Between (1) and (2) several small longitudinal woods, outriggers are struck.
(4) There is a soft plate to finish the underside of the projection of the edges
The back of the edge board was let into a groove and nailed to the outriggers.
Building an edge ladder is simple. Lift it in place and nail the plywood ‘side’ of the ladder to the last trussed rafter on the gable end. Side Nail Outriggers to the Runner at the Top of the Wood Frame Panel. It became work.
The ends of the ladder are cut to a splay that matches the pitch of the roof so that it can be easily attached to the eaves finish, tucked in front. The eaves finish can be pre-made. First, the ends of the rafters of the trussed rafters should be cut to the correct angle and length.
For better understanding also watch,
The ends should be in a straight line. The easiest way to achieve this is to expand a
The chalk line at the top of the rafter shows the correct distance from the wall face,
Draw the line tight and lift and release – snap the line – against the rafter ends. The chalk line is made in the rafter – it is in direct line with all the others.
Cut to the right angle and the work is ready to accept eaves boxing. Figure 6.24 shows one way of doing this. After the rafters are all cut, the fascia And can be put on soft plates.
Prefabricated, they come with a soft plate that attaches to the fascia, and some rectangular off-cuts of wood are pinned and glued to keep it soft and fascia-free. Right angles. The entire unit is fed to the ends of the rafter and is nailed to its ends Rafters.
The most traditional method is fixing brackets for rafters, fixing fascia Place it on the rafter ends, then gently scrape and nail it to the brackets.
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