Well, I've just spent half a day in the loft adding insulation and boarding - and have only done half of it. As well as lath and plaster there is the original 1930s wiring (no longer live) and new wiring that goes all over the place so job one was to remove the steel pipes filled with 1930s fabric bound electrical wires, and to get all the wires out of the way of the insulation (so there's no risk of overheating.

I'm keen to have a boarded loft, and didn't want to go with the insulated modular boarding option (too expensive) or the option of extending the joists so I've gone for the plan of adding mineral wool between the joists, boarding over, adding XPS board or something, then boarding again. Complicated, but cheaper and hopefully easier to fit round all the timbers.

The cut to fit 100mm thick stuff was quite hard to find - everyone has the 200mm stuff that you put over the top, but I had to go to three stores before I found one that did it (Homebase in Ewell). However, it was really good - not very itchy and easy to cut to shape with scissors into the various thicknesses and shapes.

The boarding was just 20mm chipboard which I bought in a couple of big sheets, then the guys at Homebase sliced it into 40cm wide strips so I could fit it up through the loft hatch. I then cut it roughly to shape in the loft and screwed it down to the joists.

So now next step is stage 2: getting into the side loft above the extension (where there's currently no access), and stage 3: an extra level of insulation boarding above the mineral wool between the joists. Watch this space!