Status: Planning Permission Granted

Building Cost: 150k

This property comprises a modern split-level terrace house. Primarily built in reinforced concrete and exposed masonry. The homeowners feel the house is partially underperforming and as a result, some improvements will have to be made, to guarantee the property's longevity.

The project focuses on the rear glazed structure, called ‘the conservatory’. The conservatory is south-facing, placed at lower ground level, poorly insulated and lightly shaded.

In broad terms, the homeowners have experienced excessive internal heat gain (overheating) mostly during the summer months, in contrast, during the winter months the room is cold and the glazing shows condensation. It is also noted, that the entire house is not adequately thermally insulated, with some thermal bridges and thermal bypass, consuming more energy to heat it.

The proposed design introduces a green roof to reduce heat absorption, enhance biodiversity, reduce flood risk and promote a small microclimate while softening and contrasting the proposed brickwork. To the left of the single-storey new extension, an openable window (sub-divided into 3 panels) is being proposed, to the right a single patio door would enable access to the existing rear garden.

A hand-made brick wall (new rear cavity) facade is being proposed, using bricks would be more in- keeping to the original appearance of the house, and it will be designed to have a slightly modern and contrasting character.

The new fenestrations will maintain views of the rear garden, incorporating low-E double glazing and restricting the window’s height will improve the driven-comfort approach. The openable 3-panelled window would enable passive ventilation. The new limestone external window cill will be used as a bench, creating a more subtle outdoor seating area.

All windows are openable and can be left open for longer periods (with a built-in insect mesh).

When testing the daily temperature over the critical months, the ‘new conservatory’ has an average temperature of 18.66 in the warmer months (see graph to the right). A peak, of 23.31C. This meets the comfort-driven recommended internal temperature.

The new glazing panels have also been modelled and tested, and the results indicate that levels of direct sunlight have been reduced to acceptable levels in all of the glazed panels.

Solar radiation levels are low and stable across all glazing, resulting in almost ideal thermal comfort. We believe that there is a low risk of overheating.

The built-up of the new flat roof dramatically improves thermal performance, the results after testing give a U-Value of 0.16 w/m2k effective under Part L, Building Regulations.