A Biomass Boiler House is part of the district heating system to supply heat energy (for heating and hot water) to the existing and future Hooke Park campus buildings, using woodchip from the Hooke Park woodland.
It is a semi-below-ground building that consists of a boiler room (that will house the woodchip boiler and accumulator tank) and a woodchip fuel bunker to which woodchip is delivered and then screw-auger fed to the boiler.
The walls of the Boiler House will be constructed from stacked curved timbers sourced from trees that have naturally grown with curvature. The students established a system for scanning the standing trees and strategically placing them to form a sinuous doubly-curved wall.
The final stages of decking the roof and installing the handrail are underway.
With a scaffolding deck at shoulder-height, we are now working on stacking and fixing the upper courses of the wall.
The stacking of the douglas-fir elements to form the Boilerhouse wall is now well underway. Each course is of a different thickness, depending on the available logs, and is screw-fixed to the one below through packers and wedges.
With the formwork fully in place, we were able to pour the concrete for the walls and then strike the formwork to reveal the first completed section of our Boiler House.
We have continued with the formwork for the concrete walls: making the formwork, filling any holes, sanding it back and installing it on site.
The building consists of a low concrete wall, topped by a sinuous, curved wall of logs. This is not a conventional building method so we have been testing connection details at 1:1.
Working in conjunction with the appointed contractor, we have been preparing the site and steel reinforcement for pouring the concrete slab.
We are processing the logs from felled tree to cut, grooved and peeled logs ready to stack and form the curved wall of the Boiler House.
We have continued assembling the formwork panels, following CNC-cut profile curves.
It turns out that formwork is much more complicated than the resulting wall. The boiler house has a concrete slab foundation system and the curvy log walls sit upon curvy concrete base walls. We decided to create frames which could create the inner and outer walls and then clad them in plywood which can bend to the shape of the curves.
Today we have been testing various options for minimising the risk of rain penetrating through the log walls. It was decided that an angled cut of 30° will be cut along the outer edge of every log. Where the logs meet horizontally, a strip of expandable foam will be inserted within the joint.
Before anything could happen on the site we cleared the overgrown vegetation and fenced it off. We then set out the boundary of the building in order to know how much of the earth needed to be excavated.
We underwent a process of 3D re-scanning some of the felled trees so that we have an accurate record of the curvature of each log. The information from the scan is then put into the computerised Rhino model, where the optimum curves will be allocated to the most appropriate position.
Working with the Hooke Park forester, the scanned trees were marked for felling and then cut and extracted, and carried to the campus yard.
Charlie and Edward have been helping us build a prototype tool to cut the top and bottom flat surfaces on each component. This first version consists of a workshop bandsaw re-mounted on a rolling trolley to make a cut parallel to the floor.
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Working iteratively between digital and physical models, we have composed a geometry for the boilerhouse wall. Each 3d-scanned tree trunk was CNC-cut at 1:10 scale, and stacked according to the script-determined best-fit sequences.
We’ve been experimenting with tree scanning techniques, using a Kinect sensor. The plan is to 3d scan all the Douglas Fir trees that have “basal sweeps” (curved lower trunks), and then select and compose them to form the Boiler House wall.
The scheme design was presented in London today at our end-of-term jury.