Crazy and Complicated Truss Designs – Part 11

Crazy and Complicated Truss Designs – Part 11

Let’s start at the beginning. A component designer’s job is to iron out any kinks in a design, while practicing humility. No one is perfect, and mistakes are made at every level. A designer must not only have the ability to find any issues, but also must be able to help the building construction go as smoothly as possible. Some plans are very intricate and some are straight forward. However, every now and then you run across a plan that is both complicated and in black and white, so to speak.


This project is a multi-story residential dwelling. It is quite a beautiful design and fairly straight forward. The complication became apparent concerning the varying plate heights, cantilevers, and beam locations.


The basement ceiling indicated a uniform main level for the most part; however, there were three areas where the floor was sunk in heights ranging from 6”, up to 16”.


In addition, heading up from the basement there is a den located at a landing on a wrap-around stair case. The floor of the den started about 3’ above the slab instead of the approximate 8-1/2’ where the rest of the floors were specified.


The aforementioned wrap-around staircase continues to the second floor. Again, there is a landing where the library is located. The library is directly above the den and has 14’ ceilings; however the floor of the library is about 5’ lower than the rest of the second floor.


Now, on the first floor there is a kitchen, eating area, and a great room which all have 12’ ceilings. Therefore, the floor of the second story above that area is 2’ higher than the remainder of the floor on the same level. The master bedroom, ensuite, and dressing room have the floors that are at the higher plate height.


In order to get into the master bedroom, there will be a small set of stairs and another landing. Also, there are two additional staircases on this floor that head up to the third floor. A private staircase is located in the master bedroom and one for other family and guests is near the front of the house.

On the third and final floor, there is a sitting area at the top of the stairs from the master. A loft and bedroom/bathroom area is accessed by the other aforementioned set of stairs. And this is where it gets interesting. Both the master bedroom area, including the ensuite and dressing room, and the entire third floor share the same roof planes.


So, now the varying floor heights, ceiling height changes, and vaults all need to be compensated for. Differing heel heights did the trick for the plate height changes and the vaults are definitely in a designer’s magic bag.

The main issue with the cantilevers was that some of them on the interior of the house are meant to pick up a load from above. So, starting from the top down, roof trusses bear on a wall that sits on the cantilevered end of an I-Joist. From the end of the cantilever to where the I-joist picks up bearing is only a little more than a foot. All the varying wall heights made for some interesting truss profiles!


Now, the wall that is supporting the first I-joist is also sitting on the end of a cantilever. Again, the second cantilever is only about a foot. The supporting wall under the second cantilevered I-joist then comes to rest on a beam. The needed supporting beam was accounted for in the plans, but needed to be slightly relocated.

All in all, this house was very creatively designed and from the floor plans will be absolutely beautiful. I am pleased that I had the opportunity to learn from this design as well as be a part of the finished product.

What kind of unusual designs have seen over the years?

View Part 1 in this series here.

View Part 2 in this series here.

View Part 3 in this series here.

View Part 4 in this series here.

View Part 5 in this series here.

View Part 6 in this series here.

View Part 7 in this series here.

View Part 8 in this series here.

View Part 9 in this series here.

View Part 10 in this series here.

Stay tuned for Part 12.

Ashley Casey – Design Professional

Gould Design, Inc.

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