Balcony Roof Truss Design for a Customer in Chelmsford

Currently in the design process, details have been received from an existing customer for a balcony roof truss design. This balcony required a roof over it, which is in line with the main roof area. Although this was originally drawn as a steel portal frame on the gable end with a steel ridge, our Truss Designer James Hobson advised around a full timber solution for both sustainability and cost effectiveness.

The nature of a roof which has a significant overhang can cause some challenges when designing, which James has been able to overcome. A key aspect is deflection of the truss at the ridge, as the truss is cantilevered out from the gable wall. This means that there is also a high point load from the truss through the gable wall, which may require the engineer to factor this into their designs. Working in the best interests of the customer, we will highlight the additional loadings to make sure that any amendments required will take into account the increase in load.


In addition, the rule of ‘1 third out, 2 thirds in’ has been something to consider, which relates to how much the truss is cantilevered. In order for our truss to fit correctly and stay within deflection limits, it is required to maintain a minimum of 2 thirds of the cantilevered distance back into the main body of roof. Using this ridge truss can raise design challenges when trying to form the remaining roof. James has thus made the decision to run the ridge truss through an opening created with the main roof, in order for the ridge truss to be positioned once the main section is in place.

Finally, James has taken into consideration weather influences by including additional wind loadings to rafters that form the roof over the balcony. As this area is open to the elements, wind can impact the gable wall and be forced upwards to the underside of the rafters. This causes additional uplift on our rafters and the supporting truss at the ridge, which all needs to be taken in to account when producing our designs.

By considering all possible factors that could affect the durability of our trusses in the design process, quality is confirmed for our customers through improved durability and simple installation. Unique designs such as this which pose challenges for our team are welcomed, and allow us to innovate in designs for the team to learn from.