The first task on our Phase 1 list was the replacement of the top eleven courses of brickwork as the existing ones are crumbling due to weather damage and are in danger of becoming a health and safety hazard. Now this job seemed simple enough as it is just the removal of the old bricks and the laying of eleven courses of new bricks, but there is the small matter of all this needing to happen 5 scaffolding lifts/12m up in the air. Getting materials up and down is a challenge and in order to help with this we purchased two electric winches. These were installed on the scaffold with one doing the first three lifts and the second doing lifts 4 and 5 (where the scaffold steps in with the tapering of the mill).
Winches in position on the scaffold.
Once these were operational, we could at least lift up and down everything we needed although we were limited to the capacity of the winch buckets and the 250kg load limits of the winches. Anyway, we started by taking off the crumbling bricks and winching them down to the ground. As these were coming down, we were moving the new engineering bricks up. These were sourced from a local supplier and were chosen as they were a good match to the existing engineering bricks on the top two storeys of the mill and upon which they would be laid. Once the bricks were stacked on the top scaffolding lift and the top of the mill cleaned off the bricklaying began and it wasn’t long before the eleven courses were up albeit with the need to winch copious amounts of lime mortar up the scaffold and spend plenty of time pointing it up
The new top of mill brickwork being built up.
The re-pointing of the mill was to be undertaken while all the other works were ongoing with one team working on the pointing and another on the top brickwork, roof, windows or whatever else was happening at the time. Initially every mortar joint on the entire mill was raked out with the exception of the area where the new building was going to join it as we were possibly going to leave that with the old finish being as it was going to be inside the building (hence didn’t need to be weatherproof) and it looked aesthetically pleasing. The raking out was done mainly with a specialist electric mortar saw and a small grinder where the mortar saw could not get in. The joints were fully cleaned out to about 40mm deep to give plenty of recess for the new mortar to be pushed into in order to make the repointing strong and long lasting. The re-pointing was done with lime mortar and was undertaken in areas of about 4 square metres at a time after which the mortar could be brushed off with a wire brush to give that lovely lime mortar finish. This was a lengthy process as the mill is approximately 110 square metres in terms of the surface area of the brickwork and therefore quite a task to undertake.
In terms of our plan the next job was to deal with the roof. We’d already established it needed replacing but we still didn’t know exactly how it was constructed other than the top was glass fibre. We did know, from the access hatch through it, that it had some concrete in it, but we needed to establish exactly how this was constructed, fixed and what thickness it was as this would govern how easy it would be to demolish. As such we took a concrete breaker up the scaffold and removed the glass fibre to expose the concrete, we then set to work and broke some of it out to find it was about 150mm thick and filled with metal reinforcement and in all likelihood had been cast in situ to sit on the substantial wooden beams in place across the ceiling of the uppermost room.
The exploratory ‘dig’ and resultant concrete thickness.
Before starting we had considered a number of different ways to take the concrete out including building a full scaffolded crash deck under it that we could drop it onto and stand on while we did it, but given we now knew it was reinforced this made the job easier as we felt we could actually stand on it to break it out. There were also the two large wooden beams running across the building under the concrete that would provide additional support for the demolition process. Even so we still assembled a rudimentary trestle/plank deck under it just to be as careful as possible. With this in place end we set to work with an even bigger concrete breaker (due to the thickness of the concrete) and slowly but surely managed to break up and remove the slab. Large pieces of concrete that were broken out were taken over the new wall and lowered down on the winches whereas smaller bits were allowed to drop onto the (covered) floor below and eventually it came to pass we had a mill with no roof.
The concrete removal process and the roof gone.
The only bad news we now had was the state of some of the old roof timbers with the rot situation in some of them being dire... they were just basically crumbling to dust in many places. While they were no longer needed to support the roof as the new roof would be supported completely differently we had wanted to retain them for aesthetic purposes. Closer inspection revealed that the two main original beams were saveable with one being in excellent condition and the other needing piecing in parts, but overall it was not not too bad. Every other timber was beyond repair, but it quickly became apparent that these were not original as they were cheap softwood cut differently to the originals and as they were no longer going to support anything their removal didn’t really matter. Therefore, we did exactly that and patched up the holes in the wall where they used to be prior to setting up planks across the remaining beams, off which we could now work to build the new roof. It was our intention to eventually restore these remaining two beams and make a feature of them in the room so we were careful to protect them from any further damage.
The state of the timbers and the ‘room’ open to the elements after their removal.
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