My extension was built and I'm about to start laying topsoil and grass and generally finishing off. I'm a little unsure of how high I can go with the topsoil. Obviously I can't go above the damp proof course and that's too high up anyway but I'd like to go about 2 bricks below it as that's what it is around the rest of the house. However there are gaps between some of the bricks that low down - it's about 5 bricks between gaps. Can I go up past this level or are the gaps there to let air in?
Thanks
-- John Kelly
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