Fastener size for steps to outdoor deck

[tominboise]

I am installing three replacement stair treads at my cabin. These stairs go from ground level to the porch. One set has two steps, and one set has one step. The stringers are made from round logs cut in half lengthwise so it is half round, half flat.

The stair tread itself is 4 X 10 pressure treated timber, 48" long. The tread will sit on 1-1/2 X 1-1/2 angle lagged to the stringers. There are 4 lags going to the stringer and 3 lags going up into the bottom of the tread, on each angle. I made the angles 9" long and drilled all the holes 17/64". My two choices for fasteners are #10 X 2-1/2" (Simpson SD) or 1/4" X 3" (Simpson SDS).

The 1/4" seem to be the logical choice, but maybe overkill and the #10 are fine.

Any opinions?

 

[PCustoms]

Either should be fine, I'd lean towards 1/4 in that big a timber.

More important is the screw holding this all to the stringer, and how the stringer is made

 

[BillK]

Very hard to visualize this for me. How about a picture ? I am not fathoming a 4x10 stair tread ????

 

[tominboise]

Very hard to visualize this for me. How about a picture ? I am not fathoming a 4x10 stair tread ????

No picture unfortunately. The stair tread is 4"X10"X48" long.

 

[mike93lx]

You're worried about overkill while using a 4x10 tread?

I don't think screw selection will matter much beyond one that is properly coated for PT

 

[matt_i]

GRK-RSS in 5/16 x 3-1/8" would be my choice. Drill larger clearance holes in your angle.