The owner had bought the house as a doer-upper, in the knowledge that there was a pre-existing historical wall movement. However additional wall movement had occurred since moving in. Fortunately, rectifying the problem is not a huge task but does require the bare bones of the house to be uncovered, so 'gutting' the house for a whole house retrofit was the perfect time to address this.
Floating floor joists!
During week one we discovered that the first floor joists were not resting on the outer wall, due to the movement of the walls.
Wall plate solutions
Working with structural engineer Dan Sawyer, we've found a great solution with a new wall plate to tie in the floor joists to the wall. To address the problem of the floating floor joists we trimmed and neatened the floor joists and then attached them to a new wall plate attached to the outside wall.
Dealing with wall movement
At the same time we needed to make sure there would be no more wall movement. This involved the addition of 4 flat metal bars running along the top of 4 of the floor joists. The timber floor joists were cut out to accommodate the metal bar
The flat bars then turns from a flat piece of metal into a rod or bolt which is then bolted into a concrete pad in a hole made within the stone wall. Other metal bolts are resined into stones at different angles in the wall and then encased in the concrete with the metal bar coming from floor joist to stop the wall from moving outwards.
Insulation & airtightness
We also needed to ensure that we reduced thermal bridging and maintained airtightness around the wall plate and wall ties detail.
We reduced the thermal bridge of the metal bar/ bolt going into the external stone by making it pass through the insulated wall plate first.
The wall plate was insulated behind it with a mixture of Compacfoam (around the bolts) and PUR insulation.
An airtightness membrane XXXX was used behind that and walls parged above and below the wall plate.
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