Our company builds a dozen or more houses a year. With a crew of only four carpenters, we can't afford to waste time, so we're always looking for systematic ways to approach the work.
In this article I'll describe our method for laying out and framing a first-floor deck. The techniques we've developed allow us to work quickly and accurately, and ensure that the rest of the framing goes well.
We typically split into two teams of two carpenters. One team rolls out tools and gets the floor framing material ready while the other lays out the sills. The goal is for the sill layout to be dead square and perfectly parallel.
Framing errors and compromises tend to accumulate and show up in the roof; if the sills aren't square and parallel, the walls will follow, making the roof harder to frame. The error might even be visible when the job is done.
Longest wall. The first thing we do is snap a line along the top of the longest wall, 5 5/8 inches in from the outside face. This line represents the inside edge of the sill; its outside edge should be flush with the face of the wall. Sill stock is always a little bit wide, which is why we offset the line 5 5/8 inches rather than 5 1/2.
On a straight foundation wall, the sheathing usually ends up 1/2 inch beyond the face. If the foundation bows out in the middle more than 1/2 inch, we'll shift the line out until there is no place where the sheathing will not be at least flush to the face of the wall. This may change the size of the house slightly, but that's better than having the foundation touch the back of the siding.
Creating a Square Layout
Next, we snap a line square to the first line along the top of the longest intersecting 90-degree wall.
Crew members snap sill layout on the longest wall of the foundation.
Then mark the inside corner, and align the laser over that point.
Next, they place a target over the line at the far end of the wall and rotate the laser until the front beam hits the target dead center.
Finally, they locate the perpendicular line by placing the target on the adjoining wall so that the side beam hits it dead center, mark that location, and measure in one inch to account for the offset between the down beam and side beam on the PLS5 laser.
A line between this point to the inside corner will be square to the original line.
In the past we located this line using the 3-4-5 method or by calculating the length of the hypotenuse between the far ends of these walls. Now we use a PLS5 laser (Pacific Laser Systems, 800/601-4500, www.plslaser.com), which projects reference lines that are perfectly straight and square. It's faster than drawing right triangles and there's no need to worry about inaccuracies caused by a sagging tape.
Using the laser, we can create square layout on a large foundation in a matter of minutes.
Aligning the beam. We begin by making a mark 5 5/8 inches in from the end of the line we made on the longest wall. This represents the inside corner where two sills will meet.
Next, we place the laser on the wall, align the downward beam with the corner mark, and aim the main horizontal beam toward the far end of the wall.
Our goal is to position the horizontal beam directly over the line on the wall. To do this, we position the laser target on the far end of the wall so that the pointer lands on the line. Then we rotate the laser so it projects a dot on the centerline of the target.
On a long wall, adjusting the laser takes very little movement; for fine adjustments, we tap lightly on the side of the laser. When the beam hits the target's centerline, we know it's aligned with the chalk line.
Projecting a perpendicular line. The next step is to project a second line at a perfect 90-degree angle to the first and mark it on the adjoining wall.
The PLS5 projects three horizontal beams, two of which are perpendicular to the main horizontal beam. The main beam is already aligned with the line on the foundation, so to create a square layout we just have to determine where the side beam passes over the intersecting wall.
We do this by taking the target to the far end of the intersecting wall and positioning it so that the side beam hits it dead center. Then we mark where the pointer lands on the concrete.
With the PLS5, the side beams project at a one-inch offset from the vertical beam (in this case, one inch too close to the outer face of the wall), so we measure over an inch and use the new mark to snap a line back to the corner where the two sills will meet.
Laying Out the Remaining Walls
Now that we have two lines that are perfectly square to each other, laying out the rest of the walls is simply a matter of measuring off the first two lines. Difficulties arise only in places where the foundation walls step up and down or where we need to drop our layout onto a basement floor slab.
The traditional way to handle these areas is to stretch a tape horizontally and then use a plumb bob or level to carry the layout down. We find it faster and easier to stretch the tape and use the laser's up and down beams (the plumb beams) to carry the layout down.
To lay out sills on a stepped foundation, most carpenters stretch the tape horizontally and use a level to plumb down.
A faster method is to stretch the tape, position the laser so the up beam hits the desired mark, then mark where the down beam hits the foundation.
Once layout is snapped, we gang up on the mudsill. If the sill is to be attached with anchor bolts, three framers mark bolt locations while one carpenter drills holes.
Anchor bolts. To locate the holes, we place the sill against the bolts, align a square with a bolt, and scribe a line across the sill at that location. We then measure the distance between the layout line (on the foundation) and the center of the bolt and make a mark that far in from the edge of the sill on the line we just scribed. The mark will be the center of our hole. It's important to do this accurately because the hole should not be greatly oversized.
A carpenter butts sill stock to the bolts, squares in from them.
Then measures the distance between each bolt and the layout line.
After marking that distance on the stock, he drills the bolt holes.
We have tried using a specialized marking tool, the Bolt-Hole Marker (Big Foot Tools, 702/565-9954, www.bigfoottools.com), but found it difficult to balance a 2x6 plate on the stem wall while making the marks. This tool is much better suited for marking plates for slab foundations.