The guy's who built your house had a good notion about how to protect the interior of the building and would have appreciated that they were building at an exposed location.
The purpose of the cavity is to separate the external element from the internal element in order to avoid penetrating damp, and the cavity also assists in drying out the brickwork from inside the cavity the damp brickwork to dry out, and I assume they must have done a good job as your not complaining about penetrating damp!
Whatever you do, you should not fill the cavity at all - it has worked for so long why try fixing something that doesn't need fixing! Also there are enough threads on this forum to do with the negative effects of cavity insulation to warn most people of the issues that can confront the occupier, even though the government are advertising to fill cavities!
What you may wish to consider is insulating the interior of the external facing walls, which can provide some real benefit.
By way of an example: Existing U value of uninsulated wall is around 1.5W/m2K, adding say 25mm thickness of PIR insulation with plasterboard finish would reduce the U value to around 0.56W/m2K, increasing the insulation to 50mm thickness would reduce the U value to 0.35W/m2K, increasing the insulation to 75mm would reduce the U value to 0.31W/m2K and increasing the insulation to 100mm would reduce the U value to 0.20W/m2K. It all depends on how much space you can afford to lose!
You may wish to consider adding insulation between the joists on the ground floor - take up flooring - install a plastic mesh to hold the insulation material, install insulation, fix a vapour barrier over the top and relay flooring.
If the wall ties are not corroded now its is likely that they are either made of wrought iron, or a replacement job has been done - you would not have the galvanised fish tails or mild steel butterfly ties as the property is too old.
I hope the above is of some assistance to you.
Regards
The purpose of the cavity is to separate the external element from the internal element in order to avoid penetrating damp, and the cavity also assists in drying out the brickwork from inside the cavity the damp brickwork to dry out, and I assume they must have done a good job as your not complaining about penetrating damp!
Whatever you do, you should not fill the cavity at all - it has worked for so long why try fixing something that doesn't need fixing! Also there are enough threads on this forum to do with the negative effects of cavity insulation to warn most people of the issues that can confront the occupier, even though the government are advertising to fill cavities!
What you may wish to consider is insulating the interior of the external facing walls, which can provide some real benefit.
By way of an example: Existing U value of uninsulated wall is around 1.5W/m2K, adding say 25mm thickness of PIR insulation with plasterboard finish would reduce the U value to around 0.56W/m2K, increasing the insulation to 50mm thickness would reduce the U value to 0.35W/m2K, increasing the insulation to 75mm would reduce the U value to 0.31W/m2K and increasing the insulation to 100mm would reduce the U value to 0.20W/m2K. It all depends on how much space you can afford to lose!
You may wish to consider adding insulation between the joists on the ground floor - take up flooring - install a plastic mesh to hold the insulation material, install insulation, fix a vapour barrier over the top and relay flooring.
If the wall ties are not corroded now its is likely that they are either made of wrought iron, or a replacement job has been done - you would not have the galvanised fish tails or mild steel butterfly ties as the property is too old.
I hope the above is of some assistance to you.
Regards
