Hi. First post here...of many I expect.
I'm renovating some old stone cottages, which have external walls that are about 600mm thick. I'm taking out large flue pipes from old boilers and need to fill the holes with something, but I'm not sure what to use. The holes will be 250mm (w) x 350mm (h) x 600mm (d). I can brick and render the inside and use stones and lime mortar to match the stonework on the outside, but what would you recommend for the middle of the hole? Loose fill with rubble and spray foam insulation maybe?
All help appreciated. Thanks.