week 2: structural alteration beneath the house

There is a vast void beneath the house, thanks to the slope that the house is built on. In its present state, it cannot be effectively used due to the amount of structural walls and supports. Some of these are now being demolished and replaced with lintels on block piers. The photo above shows the block piers constructed on top of the existing retaining wall. Elsewhere, access hatches are being cut into the walls as can be seen in the photo below.

Opening up under the house in this way allows the space to be used more effectively. The part of the void in the photos (with the greatest headroom) will be part of the heated volume of the house and will become a plant room for the hot water cylinder and an archive/storage area to house items currently in the loft. The loft will be almost unusable for storage due to the amount of insulation proposed and its low (22°) pitch.

The void will also enable good access for installing the new services: pipes, cables, ducts, and will be excellent for getting the floor insulation into the unheated part of the void toward the front of the house where it becomes more of a crawl space. The drawing extract below shows the extent of the void and the delineation between heated and unheated areas (insulation and air barrier line shown in green).

week 2: structural alterations

In meeting the structural engineer, it was agreed that the lower ground slab should stay for the time being as it will be easier to temporarily prop the upper slab from this. In the meantime we have been deciding the best approach for the main structural alterations and the insertion of the steels.

First of, five of the seven side windows have been in-filled, the remaining two will come out later. In-filling the windows will strengthen the wall prior to the demolition of the lower section of this wall.


Exposing the slab edge reveals that it is supported entirely by the inner brick leaf. This makes the sequencing simpler as the slab can be supported as proposed, with an array of Acro supports below. The outer brick leaf will need supporting independently, but there is not as much load to contend with as we thought. As the sketch detail above right shows, we have a slight clash with the proposed steel now and we will need to trim the top flange such that it doesn’t foul the inner brick leaf. Our structural engineer is okay with this providing we bolt the web of the steel to the edge of the concrete slab.