A temporary cap

Now that the curb is finished, we have been building a temporary roof for the tower. This will keep the weather out, allowing the scaffold to be taken down. We will then move on to the rebuild, off-site, of the cap.

Starting to board out the roof. Excuse the soulless OSB, it is only temporary!

Boarding finished, and felt going on.

The finished roof, with chicken wire under the eaves, to keep the birds out and still allow ventilation.

Curb complete!

Over the last few days we have been finishing off the curb and fixing it into position. Here are a few photos showing the developments..... 

 

The curb, with metal track let-in. This acts as a 'ball-race' for the rollers which will allow the cap to rotate into wind. The large nut just inside the track is for one of the holding down bolts. Inboard is the guide ring, which, er, guides, the cap as it rotates around the curb.

 

Under the curb, showing a holding down bolt concreted into the masonry. The curb is temporarily propped up, to be lowered later, sliding down these bolts. This method allowed us to tighten the various bolts/nuts holding the curb and guide ring sections together, prior to these being 'lost' under the curb when it was lowered.

Ready to be lowered

Lowering on three chain hoists simultaneously, onto a bed of mortar. Note the lack of overalls due to working in the 'greenhouse' section of the scaffold, in 25 degrees heat.

Level and position checked, the curb in its final (we hope!) position.

Guide ring pieces

We have started to make sections for the guide ring, which will be fixed to the curb. Our new portable bandsaw is proving to be very useful for tasks such as this, we don't envy the original millwrights cutting by hand. Once planed and cleaned up, the sections should (will!) fit together as per the curb last week.

The curb begins to take shape

So, the nine sections for the new curb have been cut and pre-drilled for their holding down bolts. After checking the layout on the ground, the sections were then hoisted to the top of the mill and laid into place. Thankfully, everything lines up (never in doubt!) The next job will be routering a channel for the sections of metal ring which will be sunk into the curb, providing a 'track' on which the cap can rotate.

Hoisting, a time consuming two-stage process for each section

The first few sections going into place

The complete ring

Windows with a view, and more masonry.....

Finally, we have finished the re-pointing of the tower! The next masonry task is rebuilding the top of the tower, to give a firm bed for the curb. The original outer and inner 'skins' of the tower are in fairly good condition, but the loose infill appeared to have been carried on right to the top. Consequently, when the rotten curb was removed, quite a few stones fell away with it!.

Using a template arm, pivoting around the top of the main upright shaft, the loose stonework is repaired to the correct level. The oak curb sections will then sit on a bed of mortar, to give a bit of leeway for final levelling. The originals were held down with coach screws, driven into timber blocks which had been set into the tower as it was built. A hole for such a block can be seen above, just in front of the template. We are proposing to fix studs into concrete poured into these holes, as retrospective fitting of timber, with an acceptable degree of security, is impractical.

It has also been good to see the new sash windows going in; it makes such a difference to the feel of the building. They have already been tested for weather-resistance, courtesy of the extremely heavy showers this week. We always get a good view of the incoming weather from the top of the tower !....

An update on progress.....

So, the New Year's Resolution to keep more up to date on the blog hasn't quite panned out! Anyway, with the recent cold weather making masonry work impractical (frozen lime mortar doesn't work very well), we have shifted our attention to the cap.

'First-aid' repairs in the '70s did a good job of preserving what was left of the cap. However, the deteriorated condition of the timber means that much of it will have to be replaced, using the originals as evidence of how the cap was constructed. In fact, the cap turns out to be quite a confusing mixture of original material, old repairs, more recent repairs and some mystery items (repaired repairs?!)

So began the process of stripping the cap, recording the evidence as we went, prior to sorting through what can be re-used.

At this stage, the aluminium cladding and felt have been removed, together with some of the ribs, here propped against the curb.

 

This is looking down on the front of the cap, with all the ribs removed. The weatherbeam is rotten, as are the front ends of the shears.

A section of the curb, showing its generally poor condition (rot and worm).

And finally, with everything removed! This picture doesn't quite convey the mass of items which were lowered to the ground: aluminium sheeting, ribs, weatherbeam, shears, brake arm, winding gear, truck wheels, centering wheels and a lot of ironwork.

We have also been making replacement sash windows:

Evidence from remaining parts show the original windows were sash but with no weights, presumably wedged open as required. So, that is what we have made. Once fitted, they will be a great improvement over the chicken-wire / Tyvek combination currently in their place!

All wrapped up for Christmas

The mill is now slightly more conspicuous, with a full scaffold and roof. This will help with the continuing repointing and replacement of the outermost lintel sections. Further down the line, the protection of the scaffold will be crucial when work starts on the cap.

With our first proper close-up look at the upper section of the tower, it is apparent that the masonry on the south side has suffered quite badly from frost. Presumably, this type of damage prompted the rendering of the upper part of the tower, but we hope not to resort to that!

Meanwhile, during the bad weather, we have been in the workshop repairing the wallower and making replacement sash windows. There has also been some repair work for us at nearby Wheatley windmill, so, all in all, a busy end to the year.

Merry Christmas, and see you in 2012.