I've built a 12 by 8 platform that's 8 feet up in the air, and there's no way to get behind the outer beam now without complete disassembly (custom cut around a chimney). I should have followed my intuition and used 3 inch lag screws to join the cross beams, but I followed a contractor's advice and used nails. Now that the joints are pulling apart, I need to add screws from the inside, down the length of the Cross Beam, into the outer beam. What kind of screw and length would be best that will grip the outer beam and close the gap? I tried to add a picture, but site won't cooperate.
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