At last! The gutters that have been causing the leaks in our house, via the cavity of the wall (see earlier post), have been removed. These took some grinding – three cuts needed to get them off and flush with the wall (see orange elements in drawing below). The plan now is to extend the rafters such that the roof overhangs the new external wall insulation and so that we can fit a conventional gutter system.
In addition to them having failed, these concrete gutters were one of the most significant thermal bridges in the house. As shown in the drawing below, we are planning to wrap external wall insulation across the top of the roof and link it to the loft insulation layer. This will significantly reduce the thermal bridging from the remaining elements of the concrete gutter system.
The timber structure for the extension roof commenced this week. It includes three, large triple-glazed rooflights to maximise the daylight to the studio and the stairs. The roof structure will be covered with Smartply OSB3 and 150mm of Kingspan TR26 insulation prior to the waterproof layer and the sedum blanket.
The structural steel for the breakthrough to the extension from the existing hall was put in this week. The opening will be 2m wide, enough for access to the stairs down to the lower ground floor and to get to the studio on the ground floor.
With the cold weather now setting in, we decide that it is best to leave the masonry in place beneath the steel. We will need to remove at least the outer leaf shortly in order to close off the cavity prior to injecting the cavity wall insulation.