22. Installation – bottom end of liner Now give some thought to the bottom end of the chimney. The bottom end of the liner must terminate into a twin-wall adapter. The liner slides between the double-sleeves of the adapter so that it is fully protected inside and out. It must be secured in place using self-tapping stainless-steel screws and adhesive fire cement. XXIt is standard practice to fit a length of steel or cast-iron fluepipe between the stove and liner to protect the liner from flame impingement. The illustration at right shows the stove fluing straight off the top. Most stoves allow you the option of fluing off the back using a "Tee." The pros & cons of these two methods are discussed earlier in this section. XXIf you plan to use a loose backfill material like Micafil, you will need to prevent it from leaking out at the bottom. A simple technique is to use a rockwool 'bung' to close off the void. (Rockwool NOT fibreglass loft insulation which is liable to melt!) If the void is cavernous at the bottom, an alternative is to close it off using a horizontal register plate made of light sheet steel (press here for further details.)