Preparing sash window for restoration

The red room has a smaller second sliding sash window of traditional wooden construction. Its ropes have been removed, it's painted shut, and an additional stained glass pane has been added to the lower sash by the previous owner.

Once the many layers of paint were removed, it became apparent that the sill, frame, and the lower sash had rotted a fair amount around the lower joints. Overconfidence set in and the decision was made to repair and restore, rather than simply gloss over it all.

The first step was to remove the two sashes - the sliding parts of the window that hold the glass - from the window frame. Jim Sear has shared a wealth of information on sash window renovation on his YouTube channel. And the below video covers dismantling them quite comprehensively.

There are two sashes, named for their position when the window is closed. The upper sash is outermost and the lower sash is innermost; both sashes run vertically with beading holding them in place. The disassembly process is illustrated in the following sketches.

The staff beads keep the lower sash in place. They're mitred at the corners and held in place with just a couple of nails, making it easy to prise off with a hacking knife. I used this Draper hacking knife, it's nice and sturdy and stands up well to hammer blows on its spine. It was easier to remove the longer staff beads first as they have more flex to allow them to bend and pull out of the mitre

Staff beads highlighted

With the staff bead removed, the lower sash can be lifted out. Usually this would require the removal of the sash cord, but this window already had them cut.

Lower sash highlighted

The upper sash is held in place by the parting bead, which is seated in a groove in the pulley stile. I understand that this should mostly be a friction fit and so removable with just a pair of pliers, however this window had some nails driven into it. This resulted in the parting bead snapping as it was forcibly removed.

Parting beads highlighted

The upper sash, accessible with the parting bead removed, was stuck shut with a mix of paint and nails and required some convincing with a mallet before it could be lifted out. Not knowing quite how it would come loose made it a worrying task.

Upper sash highlighted

Finally, with both sashes removed, the pulleys can be assessed and removed if necessary. The pulleys in this window were quite corroded and didn't spin freely and will be getting replaced. Also accessible now is the weight pocket.

Pulleys and weight pockets highlighted

I had to use Jim Sear's trick of partially driving a screw into the window pockets to allow them to be removed. The weights were thankfully still in there, albeit tightly wedged at the bottom, presumably having fallen after the cords were cut.

Weights wedged inside the pockets

With everything removed that needed removing, the newly exposed paint could be scraped off and the sash-less window weather-proofed. Knowing that I'd need repeated access to both the inside and outside of the frame, any covering needed to be repeatedly removable without damaging the stone, brick, or window frame. I settled on using OSB on the outside, secured using long carriage bolts to reach through the opening to some wooden braces. This effectively clamps the around the window frame.

The shutters highlighted

Due to being unable to fit longer sheets of OSB in the car, the shutters were put together in two parts. This did have the happy side effect of being able to remove just the top of bottom half and work at the window a bit more safely.

I got the local timber yard to cut the OSB into the correct width and then used a hand saw to cut the pieces to the right height. To waterproof the gap between the top and bottom shutter a small offcut was glued and screwed on to the bottom of the upper shutter, with a fillet of silicone sealer on top.

The resulting boarding up solution is effective and causes no damage.