Where a new wall joins an existing wall, a vertical cut in the outer skin of the existing wall is required to effectively join the cavity walls and prevent migration of damp across the join. Two cuts were required at the rear right corner of the original house and in the front wall where the new porch side wall joined. These made, the internal wall block work was built up to half window height using gray thermal blocks with wire ties cemented in ready for the outer wall. Insulation was fixed to the block work and then the outer walls were built up to the same level. Considerable care was taken to get the best match for the reconstituted stone blocks for the outer wall with those of the original house. The mortar was coloured to match the original pointing.
After a very long pause to allow the lower courses to harden (or the builders to complete another job perhaps!), the walls were completed and the scaffolding erected to allow the roof trusses to be fixed into place and the gable end wall to be completed and tied into the end truss. Next the roof was felted, battened and tiled to match the main roof, and sealed against the side and front walls of the original house with lead flashing. Finally matching wood barge boards and rainwater guttering were fitted. By now we were into the incredibly wet autumn of 2000, so it was a relief to achieve a weather proof and secure status with the fitting of the two main UPVC windows, the front door unit and two small porch windows, and the relocated old kitchen door at the back of the extension.