Project: Completion of a Residential Loft Conversion at a 226 Newmarket St in Norwich
HA Consulting Engineers was engaged to create a load bearing design, transforming the attic space into a living area complete with first floor alterations.
Working with the architect, we were required to provide structural engineering design calculations and full details for the Building Regulations application.
The main constraints of the project were as follows
- Converting the loft of a Victorian terrace house including a large dormer window into useable living space.
- The original timber cut roof comprised a timber ridge board, common rafters supported by timber canted purlins with ceiling joists and binders.
- Hence the original timber rafters and ceiling joists needed strengthening or replacing to support the additional ceiling self-weight and increased floor loads respectively.
- Additional strengthening to the roof was required due to a dormer window in one side of the roof which caused an imbalance in loadings.
The existing floor joists and rafters did not offer the structural support necessary for an additional living space.
Converting the Rafters
In order to convert the rafters
- Rather than performing the costly process of replacing rafters, we calculated how much weight the existing rafters could support.
- Using these figures we were able to specify new strengthening timbers to carry the additional loads.
- Matching the new timbers to the shallow depths of the existing rafters allowed us to maximise the headroom in the loft area – a critical factor in the usability of the space.
We completed the necessary calculations to strengthen the rafters without having to enlarge them
Strengthening the Timbers
Working with the timbers
- A similar design approach was adopted for the ceiling timbers, with new floor joists supporting the increased loads.
- By strengthening the existing timbers we managed to keep the integrity of the first floor ceiling, allowing full occupancy of the property throughout the conversion works.
A similar approach with the floor joists allowed us to preserve the headroom in the attic
The final outcome of the engineering work
- The client was incredibly pleased with our design approach as it enabled their young family to stay in the house preventing any upheaval and disturbance.
The project was completed in such a way that the young family occupying the property did not have to move out