2 garage openings, one at 3.75m and the other is 4.8m. Im pricing up the lintels this week but dont know wether to go for concrete, rsjs or catnicks. On wicks site, the catnicks look not to expensive but how do they fair against a rsjs in price. Concrete will come in cheaper but in 2 minds will these be efficient. Have worked on garages with double and triple 3inch concrete lintels and never had any issues. ISnt there thicker concrete lintels on the market. If so, is there a limit to their height?