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I have to fix a metal top rail to an opening that was for a patio door before an extension was added to my bungalow. The bungalow was built in 1969 and I know the outer skin has a steel RSJ and I assume the inner skin is a concrete lintel. The manufacturer recommends three inch screws "in appropriate fixings". I will try a masonry drill but what fixings should I use? The rail has to take the weight of three doors. Hope someone can help.
Tonyonly

you can use 50mm stardrive fixings, really strong no rawplug required, with 75mm screw it might hit the reinforcing,you will need a cordless to screw them into position