Timber Truss Design Styles
& How to Find Your Unique Truss
Finding your unique truss style is both rewarding and fun. It will have a very large impact on how your timber space feels. As you move through the process of getting your timbered living space, you may notice more insight into your style preferences. You'll also notice that building practicality will influence your truss design.
Which is why it is good/important for you to know that your original idea will probably change as you gather more information and talk with your friends about what you intend to do... Because you plan to enjoy you timber living space with your acquaintances also, and in many ways they know us better than we know ourselves. The following timber truss style descriptions have been combined with tips on how to increase either the strength or the elegance factor so you can make your timber truss unique!
- Multi-Web Truss
- Parallel Cord Scissor Truss
- Lane Truss
- Glue-Lam Modern Truss
- Gambrel Truss
- Compression Ring Truss
Simple Truss
The simple truss examples shown here really is a lesson in simple elegance. If you are the type of person who is un-pretentious and straight forward this may capture your personality well.
Simple Truss
The no frills solution this truss presents is ideal in many situations, especially as a second act. Behind a more ornate hammer beam front truss for example. As you can see the size of the simple truss is limited to the load bearing capacity of its member- this means your typical truss span will max out around 30'.
King Truss
The king truss is probably the most common used style of exposed timber trusses... There is an explanation for this- Timeless Geometric Beauty! A cross cultural gem that can really be adapted to fit any style arched bottom timbers and curved webs dial up the elegance factor and are commonly used.
King Truss
A common mistake you'll want to avoid if you choose a king truss style, is positioning the angle of the webs 90 degrees or perpendicular to the sloped/top beams. This is a mistake repeated often, probably because it seems easy and natural to align the webs at right angles to the top cords, but it really kills the balance- the center of the truss will appear pinched or cramped, especially so with the lower pitched trusses. I believe it is better to align the webs by eye to achieve the best balance- the same principal applies when your are deciding how much arch to apply or how much to raise the bottom member if your criteria so dictates- you will be working with factors such as wall height, room volume , truss spacing and roof slope to arrive at the best decision for your situation.
Queen Truss
What is special about a queen truss? The most significant aspect is the kind of style it lends itself to.
Queen Truss
Think craftsmen or style, this special truss design also balances well if you have a tall space to fill. Lastly, the queen truss allows for display or storage space. One particular client planned to display an old large canoe. Naturally resting in the rectangular "storage space," created by the spread out queen posts.
Scissor Truss
Here is one of my favorites, the scissor truss! You have so much flexibility and can do so much to balance and capture the exact feeling you want for your timbered space. Before I list all of the available options for you, I should mention that this truss style doesn't work well if you need to tie knee braces from your truss, down to your posts, such as a free standing outdoor pavilion. I have only found two designs to stylishly achieve lateral bracing in conjunction with scissor trusses. I just wanted to make you aware of the constraints before diving into all of the many scissor options that are available to you.
- Offset centerline
- Iron rods and integrated arches
- Variable slope
- Multiple webs
- Double Top load or DBL B.C.
Scissor Truss
If you have a space where two opposite walls vary in height, you may be well served with a scissor truss- the peak, or center line is off set and aligns where the two roof scores converge- a perfect way to elegantly bridge two different wall heights.
Wrought iron rods... horizontal tie rods to be precise. A very good looking scissor truss we had the opportunity to do combined arches and a horizontal tie rod- A modified scissor truss with arch borrows elements from the Queen truss- the bottom cords begin as a normal scissor truss but then terminate a vertical post placed at approximately 1/4 to 1/3 span, a tie rod connects the bottom of these vertical posts and an arched berm connects the posts together near the top. It's a very unique truss which feels like an elegant throw back to castle days.
Another nice twist you can get with a scissor truss is to implement a ½ lap with the bottom members, This allows the bottom cords to each continue to the top member creating an "X" that really resembles scissors!- This also increases the strength of the truss because the pieces are interwoven. Bigger spans will allow you to experiment with different web angels and web orientation along with the actual steepness of the bottom members. All of this will allow you to the intimacy of your timbered space.
The Scissor Truss really blends well with all styles- western rusure, contemporary, Old European and perhaps could fit a cottage bungalow style if the roof pitch is low to keep the space intimate.
Mono Truss
The mono truss also can be a scissored mono truss amongst other things. I see space intimacy as the biggest reason to slope the bottom cord of a mono truss! If you have a need for a mono truss, I'll wager that you have a unique style.
Mono Truss
A vaulted ceiling --------- terminates at the beginning of an upper level or overlooking a great room. Most of the mono truss applications I have seen have been secondary act. That is to say that the mono truss is normally used as a stylish solution for a portion of your living space which a hub of your living space. Also certain styles combined with unique home site/visitor access can create perfect conditions to use a moo truss for your entry solution.
Hammer Beam Truss
This is often referred to as the crown jewel of the Timber Frame industry, and for a good reason. It is very aesthetically pleasing. It has a well established and rich history. And you can create lofty living space and yet retain a feeling of closeness... warmth... security.
Hammer Beam Truss
Typical uses are in great rooms, churches, entries, and attached pavilions. When you choose a hammer beam truss, you will be locking in the "old" factor. More along the lines of old European style. This is very attractive. With heavier beams, angular beam details and lower roof pitch you can pull this design more into the western lodge class.
Two advantages regarding the hammer beam truss: Short pieces. This means you will not have to pay a premium price as most of the members are short. Many pieces. This means you can influence the overall feel of your living space fairly easy. To add elegance, curve the braces and trim the beam sizes. And conversely, add beam girth and straight braces for a stronger feel. Because you have so many braces your choices can have a big impact. A few things you should know about the hammer beam truss- I make sure the first knee braces at the wall posts are as low as possible-this will insure a strong strength/tension ratio #2 many people are first attracted to timber living via pictures of hammer beam trusses, but ultimately choose a different truss style as they move through the design process. Many factors can influence this process, head room, ceiling height, roof slope, room layout. And window configuration to name a few
Personally, I like to use the Hammer Beam Truss for smaller applications in home design and bigger applications for specialty use. By specialty use I mean a church, a gathering hall, park pavilion and so forth. Any space designed to handle a group of people for a few special reasons-this activity room might be an indoor pool space. Somehow I am drawn to the principle that a big space or space with a lot of volume needs to be filled with a lot of people. It seems uncomfortable to set up your own personal relaxation space in an area that is oversized.
Now when the proportions get dialed in, that's when you really get to have fun with different variations of the hammer beam truss.
Cruck Truss
This gem gives back even further than the hammer beam truss. A simple solution if there ever was one- Basically the cruck truss is formed by leaning two timbers against each other at the roof peak and connecting them well. Many examples of the cruck truss or cruck fame will use naturally curving timbers for the main bearing members to allow for more head room or useable space. These curving members also add to the beauty of the structure. You can also use a cross between a cruck and hammer beam truss to build your structure/home. This involves a long knee brace running from the peak, down to the vertical exterior posts. Many of today's steel industrial buildings simply eliminate the knee brace running from the peak to the exterior post/column and use the post rafter to pick up strength.
Cruck Truss
As far as style goes, the true cruck truss is definitely limited-you must have a very steep roof so your starting point will be mountain lodge or old European. The best looking cruck I have seen to date was built in Australia-This barn was formed with wavy irregular timbers, sawn flat on only 2 or 3 sides leaving a portion of the tree untouched. Of course best looking comes down to personal preferences and taste. But, I feel like the rounded, irregular element really was consistent with the ancient history and architecture of the cruck system.
Multi-Web Truss
Think old industrial building or big open spaces-as we talked about the simple truss, the distance the truss can span is limited to the load capacity of the top members, and by adding multiple webs you can increase your truss span. This is why multi-web truss styles are usually found in big commercial applications. Now I have seen many instances where adding extra webs really puts a nice touch to the overall looks of the truss and structure, even though they might not be required.
Multi-Web Truss
You may also see examples of metal tension rods in a multi-web truss-this was an easy way to address the tension loads without removing needless wood from the top and bottom cord, it also has a very distinct look-the rods can be black, stainless steel, or even rusted. I enjoy seeing rods mixed with structural beams. Recently, we did a log rail system which had black rods as balusters'-your options are virtually limitless!
Parallel Cord Scissor Truss
This truss is defiantly a close cousin to the multi-web truss- It's form mandates many webs to achieve strong stability. Typically this truss is used in a standard (2x4) situation where the interior slope needs to be the same as the exterior-with a timber truss applications it is used/chosen for the appearance and style it gives... more of a hard working lodge style, as in "This is a place where things get done" statement.
Parallel Cord Scissor Truss
Definitely not what I would call elegant! I would definitely consider this truss if I had a high ceiling to work with and wanted to achieve a more rugged industrious feeling.
Lane Truss
Here again is another relative to the multi-web truss. It also says "industrious" and "rugged." The lane truss is usually used to build a "hipped" roof, meaning that the roof slopes down all four sides. A "hipped" also has a continuous gutter around the whole building. The form of the lane truss, the cut off or missing peak allows you to place a truss closer to the corners than if you had normal truss with a peak. This truss has little more flexibility as far as style, especially if more truss height is available, In which case it becomes similar to a queen truss.
Lane Truss
I would choose the Lane Truss primarily for cases which structurally require this unique form, the only exception being a situation where a normal vaulted ceiling would seem too high or make the living space feel tall and narrow.
Glue-Lam Modern Truss
As the name implies, the choice of materials and the sleek lines of the uninterrupted curve, evoke pictures of exotic blue glass, contemporary furnishings, and a unique use of unusual building material.
Recommendations simply don't work as well with this contemporary style of truss, largely because the heart and some of "contemporary" means architectural surprises-Here is an instance where I could visualize aluminum or stainless steel connection plates... perhaps even the whole truss!
Glue-Lam Modern Truss
Typically this style has smaller sized members with more space between the trusses themselves, often coordinating with modern surprises such as using old corrugated metal as all covering, hanging art from the ceiling or a myriad of other neat visuals. This type of truss will definitely hold you achieve a contemporary look that still says "home".
Gambrel Truss
You may want this truss for a barn, an art studio, or an office-all of which tie to a strong connection with nature... mainly because of the almost universal shape we know as barns-I have noticed some Victorian house styles which have a mansard roof, which is basically a barn roof and all four sides. But, by any large, your choice to build using a gambrel truss will show your close affiliation to nature, farming, and self reliance both from the inside and outside of your building.
Gambrel Truss
Regarding the actual timber style-I would recommend a straight forward design-no arches and no needless timbers. That would go for the timber sizing also-nothing extremely massive, just functional like the barn itself.
Compression Ring Truss
Whether this is a truss or a roof system is up for debate-it acts as a truss in that the downward loading is resisted by members locked together in tension.
Variations of this truss configuration are a very popular way to construct outdoor living pavilions and barbeque shelters. It is really open to any timber style although a structure of ant size would acquire relatively big timbers which would be closer to a heavy rustic style. The main benefit with this truss is the unique open feel from the inside-no webs, no posts, just an open space framed with timbers! If, say, you wanted to add more of an Italian feel you could curve the whole roof. A dual pitched roof could give you more of a Polynesian look and feel.
Compression Ring Truss
For a bigger more expensive space you would want to use small trusses in place of individual sawn rafters... similar to 1/2 of the parallel cord scissor truss-you really have quite a few different ways to tweak this concept to your liking-I recommend this where you want to get a very open and energetic feel.
Conclusion
There you have a good representation of the majority of truss types which have proven the test of time. The goal of this article is to make you aware of two things!
1. Different truss styles and an idea of how you might blend or personalize yours to your liking.
2. How your choice of truss style will be influenced by: your personal tastes, width, depth, and height of your timbered space, and your location-natural surroundings, views, prevailing winds, site access etc.
Of course you have more choices than just what style of truss you get for your timber package, post size, floor beams, knee braces etc, but the choices you make with the rood or the ceiling have the most impact on how your timber space will feel, be it your get-away cabin or a community hall you sponsor.
If you found this helpful or even motivating please leave a comment and make sure to get the next article mail to you directly!
Till next time,
