Extensions

Extension into a side return. How wide can I make it?

Anonymous user 09/03/2024 - 2.55 PM

Hi, I'm thinking of a single-storey extension into our side return, most of which would be a utility room and toilet. The house is a modern three-storey town house, with 1.5 storey roof above that. The side return, to the property boundary side of the fence, is 1.6m. We don't wish to build a party wall as the building next door is flats. If I calculate correctly, we'll need 600mm wide foundations, built entirely on our property, at a depth of at least 1m (although we had to go deeper for our rear extension). A standard wall, with dab, board and plaster, would be approx. 340mm centred on these foundations. That would make the internal width of the utility room around 1070mm (after including dab, board and plaster on opposite existing wall). Could I request high insulation block on the inner leaf to gain 30mm? Is there any other way to reduce the width of this wall and gain extra width? Even an extra 100mm would allow for standard white goods, rather than shallow depth washer/dryer etc. I'm also curious as to how large a lintel could be placed into the existing 4.5 storey brick outer wall of our property. At most we're thinking of 2400mm at one end of the wall. Thank you in advance for any suggestions.