Hi Phil,
Yes, and I can think of where I might get that cheaply.
OK, let me spell out the potential downsides of using wool, as far as I can predict them.
Our roofspace is home or temporary accommodation for a number of animals. There are Dormice, mice, maybe rats, small lizards, possibly, wood loving insects etc. It's an old stone house and, whatever you do short of rebuilding, they will get in. Sometimes a weasel or stoat or pine marten will get in and clear most of them out, but in the end they will be back. A compartment full of woodwool is below the boarding and is closed at the sides and below with wood. As far as I know they have not managed to get into that.
But, clearly, wool is lovely and warm and perfect for pulling apart and making into nests, or living in etc. There was previously a layer of rockwool up there which had been 4 inches thick, but was compressed down to an inch by dust, droppings and stuff. It was pulled apart and moved everywhere by animals.
So, what I need to do is lay the raw wool around the pipes, and bind it, hopefully without compressing it too much, as much of the calorific value comes from the air trapped between the fibres, but at the same time protect it from all the animals that want to use it for their own purposes.
I had thought about getting more oversized metal piping and putting it round with wool stuffed in between. Expensive.
I like twine for binding, but something for wrapping around the wool that is not permeable by animals.
