Refurbishment to a bungalow

No, because you are just simply replacing existing. Thanks

Hi there if you have changed your roof from slate to tile be sure your roof joists are strong enough there’s a lot of extra weight in a tiled roof you may need to strengthen them

all re roofing needs to be carried out under building regs and as such should be checked by a building inspector, the fact you are changing from slate to concrete will increase the weight on the trusses as such strengthening will be required to be able to support the extra weight this will be checked by the building inspector and only he can decide if you need to get planning permission approval generally not if its a competent roofer but all councils are diffident and interpret & apply the rules differently so you should ask the building inspector what they require to complete your project, good luck alex