The mentioned problem keeps recurring. It is a box lintel on a cavity wall over door and window, the plaster cracks around it where it sits on the wall at both ends...cause is HGVs passing causing ripple like vibrations to run through house this is quite bad when they hit a bump or divot in road. The lintel supports a flat roof but there is no weight (a brick run in fact of thermal blocks, which have come loose) on the box side of lintel and this doesn't help the situation. Have patched up (filled in) cracks previously but problem returns - is there a more permanent solution? Also how can I make the lintel more secure in its place as things stand.
