The new external brick skin of the walls is now built up, and the cavity created between that and the original solid concrete walls has been fully-filled with insulation.

Wall insulation showing in new cavity at front door

The insulation is between 250-300mm thick; the variance is due to the fact that the original walls had shifted slightly over time, so in some places the cavity was slightly wider than others, and we took every opportunity to get in as much insulation as possible!  You can also see in the photo above that the cavity extends down below ground level, to the bottom of the original wall foundations, and insulation was packed down here as well to minimise thermal bridging from the internal floor to outside.

Wall insulation being packed into the cavity at roof level

The photo above shows the insulation being packed into the cavity just below the existing eaves.  The insulation is then continued up over the top of the original wall, between the rafters and into the roof space to again minimse thermal bridging at the top of the original walls.  This is the weak point of the overall insulated envelope however, as the void over the orignal wall between the rafters only allowed for around 150mm of insulation.  The roof was then extended by two rows of tiles to meet the corbelled external skin.

Wall cavity at an opening showing wall tie

The photo above shows the newly created cavity at one of the windows, and if you click on the photo to expand it you can just see the wall tie spanning the cavity four brick courses down.  These ties were secured into the original wall by drilling a hole and inserting the tie with a mortar fill and they then span the cavity and are secured in the mortar layer of the external skin.  The ties used are Teplo Ties from Ancon, which can be cut to length; traditional ties do not come in sufficient length for this sized cavity.

Date posted: July 15, 2010 | Author: | 1 Comment »

Categories: Eco homes Existing Homes

In order the take advantage of the thermal mass of the existing solid concrete walls, and turn them into a heat store for the houses, we are building a new external wall and incorporating a large (250mm) cavity fully-filled with insulation between the two walls.  This significant layer of insulation will stop the heat absorbed by the existing solid walls transferring to the outside of the houses and being lost, as it does at present.

Before we build these new external walls, a couple of steps are required first:

  1. Removal of the existing bays on the houses to make it easier to build a single wall right across the front
  2. Addition of new foundations on which to build up the new walls

The video below shows the houses with the bays removed and the new foundations being laid.  The new foundations were combined with underpinning for the existing walls to make the overall structure more secure.


Date posted: May 27, 2010 | Author: | No Comments »

Categories: Eco homes Existing Homes

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