I sent a post the other day about installing a shower tray by myself. I haven't installed it yet due to the following discovery. I have made a stand for the tray using 6" x 2" timbers and a base of 3/4" exterior ply as I have done many times in the past. I could not get the base stable so it was not 'bouncing' slightly. I decided to look under the floor by removing a screwed down section of chipboard floor. Looking at the joists I think the householder may have a problem! The three floor joists I can see running under the shower area overlap (parallel) the existing house joists by approx 6" and are 'secured' by a No.
10 screw which cannot be any longer than 4" as it doesn't protrude out of the other side. This floor was laid when Wyatt Earp and his gang converted part of the loft space (its an old house with lots of sloping ceilings in bedrooms etc) into a shower and toilet room, the original shower installation itself was a right bodge job. What is the best way to fix this problem or should he get somebody in who knows buildings? If the three joists I can see are like this the chances are the others will be the same. I was thinking of using 4" (8mm Dia) coach screws, but wasn't sure if I am best leaving it alone and let the householder get the 'professionals in. If it helps the room is approx 10 feet by 6 feet with the joists spanning the 6 foot.Thanks for any help and advice.
John