For this week, we were laid out our mud sills on top of our foundation walls. We used the techniques we were taught in class to find "square- equal lengths, widths and diagonals." Once we have determined our square area then we snap our chalk lines so we have a reference line for our mud sills, a pressure treated piece of lumber that sits on the foundation wall usually supporting floor joist. In reality those sill plates would be pressure treated, however regular kiln dried 2" inch by 6" inch sill plates can be used, without any size differences, for demonstration purposes.
Here in these photos you can see our chalk line where our square is on our foundation wall. The next photo shows also our plate after it was cut and marked for the anchor bolt then drilled with a spade bit for the washer size and a 5/8" inch bit for the anchor bolt.
Here we are clamping our girder assembly to be nailed, clamping them during the nailing process insures that the boards cannot be separated during the nailing and cup away from the other 2" inch by 8" inch boards. Dimensional lumber has a tendency to do that when it has been fastened together. If nailed a lesser amount the boards can cup, if nailed too far from the edges, the boards can cup. This would be clear from looking at the joints between each board.
In the photo with the staircase notches are our cuts where the girder will fit sitting on the foundation wall on top of the mud sill. We also setback the wood that will be touching the concrete because concrete has capillary pores that draw water to its driest areas. This process is called capillary action. This result is why we use pressure treated wood as our mud sill.
Here in these photos you can see our chalk line where our square is on our foundation wall. The next photo shows also our plate after it was cut and marked for the anchor bolt then drilled with a spade bit for the washer size and a 5/8" inch bit for the anchor bolt.
In the above and below photos we have marked the center line with a "C and L" symbol for our girder. A girder is a load barring beam running perpendicular to the floor joists. It is what the floor joists will be fastened to in the very middle of the foundation. One of those nails in the photo will be holding a string line that is going to indicate to us if the girder is straight or if it is swinging in one direction or the other.
Here we are clamping our girder assembly to be nailed, clamping them during the nailing process insures that the boards cannot be separated during the nailing and cup away from the other 2" inch by 8" inch boards. Dimensional lumber has a tendency to do that when it has been fastened together. If nailed a lesser amount the boards can cup, if nailed too far from the edges, the boards can cup. This would be clear from looking at the joints between each board. In the photo with the staircase notches are our cuts where the girder will fit sitting on the foundation wall on top of the mud sill. We also setback the wood that will be touching the concrete because concrete has capillary pores that draw water to its driest areas. This process is called capillary action. This result is why we use pressure treated wood as our mud sill.
In the photo above you can see our temporary support "T" posts and the string line running tightly above it.
