my very large back garden is very uneven with clumps of grass everywhere and its very hard compact soil i was wondering if i could spread loads of new top soil everywhere and start again or would i have to kill off all the original grass and weeds first then spread the new top soil
A good roto will certainly break up the soil.It will leave it ready for raking and clearing of stones and old growth of grass and weeds. Then lightly compact the area by treading or light roller. Rake again to provide a loose top to take seed or turf. Spend the time in preparation and you will have a good area to work with.