Just built under stairs for cloakroom. WC and basin. Need advice on waste. Nearest and only soil pipe is cast iron and through two solid walls. It's also built into an internal corner outside with no access on two sides. I don't fancy coring two walls and replacing a ground level chunk of cast for a soil pipe tee. At the mo there's a 22mm condensate from boiler in garage drilled and siliconed into this soil. What options do I have? I'm thinking of a macerator to take WC and basin waste output through 32 or 40mm and picking up the condensate pipe on the way. Expand the fitting into soil using a McAlpine bossconn. Would my condensate need a check valve as the macerator will output under pressure and could cause backflow into my boiler? Confusing. Thanks.