So – week one of our new project in Kemp Town, Brighton – we have spent the week demolishing the original conversion – and as with every job we have ever worked on there have been a few surprises, but nothing that we can’t handle – or in some cases incorporate into the overall design.
First thing to do was to demolish the ceiling in the upstairs open plan living/kitchen space to see what is there. Unsurprisingly, considering the date of
the original conversion (1995) there was very little insulation in the roof space. Less than 50mm of glass fibre wool (R value approx = 13.5 mK/W) between the joists at ceiling level meant that the ceiling had far less than the current building regulations minimum of 300mm. The previous builders had also installed the insulation in the skeiling between the rafters without leaving any ventilation space.
This leads to condensation forming on the underside of the roof. Eventually this condensation could lead to the rafters rotting and the roof becoming unstable. So we will remedy this during the conversion.
It never fails to amaze how much waste is generated in the demolition – but by carefully separating the waste and storing it sensibly we can send what can be recycled to be recycled, and reduce the amount that we send to landfill.
Stripping back the walls to expose the roof we discovered foot deep steel beams running the length of the living, dining and kitchen areas.
Our clients and us think they should be a feature of the space so we have exposed them throughout. We have looked at this together with the structural engineer and it seems that these steels were supposed to be holding up the roof.
Apparently however they were fitted incorrectly – so some more remedial work is going to be necessary – but again – nothing that we can’t work out.
Also – demolishing the walls shows us that the original build only used 40mm of Extruded Expanded Polystyrene (XPS) as wall insulation – (R value approx = 23 mK/W, remember the bigger the R the better the insulation).
This would not pass current building regulations let alone truly insulate the house, but to keep our waste to a minimum and improve the overall insulation
we have decided it is probably best to leave the front wall and overboard the area with foil faced polyisocyanurate (PIR) rigid panels bonded to plasterboard, (R value approx = 30 mW/K).
We have worked hard – the demolition has gone well upstairs and downstairs (more photos from downstairs next week) – we have made a few discoveries (see photo to the left) – discovered a few things that weren’t done particularly well in the original conversion that we shall remedy, some things that we can incorporate into the overall design and some things that we shall have to think about, but overall a good result.
More next time.