Haun_Larry_-_The_very_efficient_carpenter

Whether it's with notches cut in the side of a cliff, knots tied in a rope, ladders tied to­ gether with rawhide strips, or beautifully

crafted stairs in palaces, people have always found ways to get from one level to another. But no matter how they do it, they've always found that unifor­ mity in step height is important. Your feet get the message immediately when they come to an odd step -a Yz-in. difference is all it takes. When build­ ing stairs, make them uniform. The accident you avoid might be your own.

It isn't very difficult to build simple straight-flight stairs: All you need to know is the rise, the run, the height of the risers, the width of the treads and the amount of headroom. Transfer this information to the wood, cut and nail.

Stairwell framing was discussed on p. 49. A stair­ well is the hole in the floor through which the stairs pass. It must be at least as wide as the stairs and gen­ erally a minimum of 120 in. to 130 in. long to meet code requirements for headroom. Headroom is the vertical measurement from an imaginary line con­ necting the front edges of all treads to the ceiling overhead. It usually must be at least 6 ft. 8 in., al­ though 7 ft. is more comfortable for taller people.

Stairs need landings, that is, level places to plant your feet at the top and bottom, with enough room to open a door. If the stairway is 36 in. wide, the landing needs to be at least 36 in. square.

The distance that stairs travel vertically from one floor to the next (finish floor to finish floor) is called the total rise. You must know the total rise before you can figure out the height of each step (the unit rise). Measure from the rough upper floor to the rough lower floor, then check the plans to find out what kind of surface the finished floors will have. If they're both going to have the same surface, say %-in. hardwood flooring, then the measurement from rough floor to rough floor will be the total rise. However, if the upper floor is going to receive %-in. hardwood and the lower floor ¥a-in. vinyl, you need to adjust the total rise to account for the difference in finished floors. (In this example, you would need to add % in. to the rough-floor measurement.) A standard house with 92%-in. studs, three plates, 2xlO or 2x12 joists and a %-in. subfloor will have a total rise of either 107 in. or 109 in.

Rise and Run

-1 Unit run

Total rise

1oE1<'Total run------------

The total run is the total horizontal distance that stairs cover. Average stairs travel about 12 ft. on the level, and they take quite a bit of room out of a floor. Sometimes the total run is indicated on the plans, but often it won't be known until the stair­ builder figures it out.

A comfortable step up (riser) for most adults is around 7 in. This, coupled with a unit run (tread) of not less than 10 in. (some codes require a minimum of 1 1 in.), constitutes the average stair of today. If the risers are too steep you may feel like a mountain climber. If the risers are too low, you'll probably find yourself taking them two at a time. Always check your code for local regulations on riser height and tread width before building stairs.

The treads of stairs sit on diagonal stringers (or carriages). The number of stringers needed to carry the stairs in a house depends on the width of the stairs. For normal stairs, 36 in. to 42 in. wide, three stringers will be required. Some codes allow stairs to be as little as 30 in. wide, but that's pretty narrow. With a 36-in. width, two people can pass with rela­ tive ease. The width shown on the plans is usually for the finished stairway. The stairs must be framed wider than the finished dimension to account for drywall on one or both sides.

Straight-Flight Stairs 1 91

Dropping the Stringer

%-in. tread

Finish floor

Remove :y.; in.

With the stringer laid out, remove from the bottom an amount equal to the width of the tread This will bring each tread to the correct height.

Some carpenters like to back-cut the riser to make a deeper tread and give a different look to the finished stair.

Dropping the stringer

You now need to make an adjustment at the bottom of the stringer to keep the bottom riser at the same height as the others. This is called dropping the stringer, and the rule is to subtract from the bottom the thickness of the finished tread. Frequently this is %-in. plywood; if so, subtract % in. If tread sheath­ ing is 2x stock, subtract 1Y2 in. But note also what finish material will be going on the floor at the base of the stairs; if it's the same thickness as the tread sheathing, for example, it's not necessary to drop the stringer.

Once the stringer is set in place, the tread is a lev­ el cut and the riser plumb. They meet at the outside point, or nose, and form a 90° angle. Some builders vary this by giving the risers a backcut of % in. or so, mainly for aesthetic reasons, but also to widen each tread (see the photo at left). The risers can be back-cut by slipping the riser gauge down the blade until the tongue of the square rests % in. in from where the riser mark meets the tread mark. Then remark all the risers, making them slant back. The last tread needs to be cut % in. wider to allow for a riser board to be nailed against the landing header joist (see p. 199).

To help secure the bottom of the stair, lay out a notch for a 2x4 on the bottom front of the first riser. Just take a scrap of 2x4, hold it flush with the out­ side corner of the first riser and scribe around it. This notch will rest on a 2x kicker that is secured to the floor.

Cutting stringers

When cutting the tread and riser lines on a stringer it is more efficient to make all the cuts in one direc­ tion before turning and cutting back the other way. Start at the bottom and cut the treads, then turn around and cut the risers. There is no need to finish the cut with a handsaw unless the stringer will be ex­ posed, because most codes require that only 3Y2 in. of solid wood remain between the back of the cut and the back edge of the stringer. On a 2x12 with a 10-in. tread and 7Y4-in. riser, you will have more than that even if you overcut enough for the piece to fall out.

1 94 Building Stairs

Use a circular saw to cut out the tread and riser lines on the stringers.

Once you've cut the first stringer, check to see that it has the proper number of risers by putting it in place in the stairwell. Nail a temporary Ix fence to the back edge of the stringer so you can use it as a template to mark the others, as shown in the photo at right. Place the first stringer flat on the second, pull it forward and snug to the fence, and mark the second stringer. If you have access to a chainsaw­ type beam cutter (see pp. 145-146), you can use it to gang-cut the stringers.

Installing stringers Tohang the stringers one riser down, begin by mea­ suring down from the top edge of the landing joists and striking a line on the face of the header where the stringer will land. This line will be down one

Once the first stringer is cut, it can be used as a template to mark the others.

riser height, 714 in., plus or minus any necessary compensation for differences in finished floor and tread surfaces. There are several ways to fasten stringers to the header joist, as shown in the drawing on p. 196. One method is to use metal straps (18 in. to 24 in. long), which are nailed along the back edge of the stringer at the top and then bent around the stringer so the upper end can be nailed to the joist (see draw­ ing A and the photo on p. 1 9 6). This method re­ quires 2x6 blocking between the stringers at the top to hold them plumb. For 36-in. wide stairs with three stringers, you will need two 151 4-in. blocks. Nail a block through the side of the first stringer, flush with the top. Pull it up to the line on the header joist and secure it with nails through the block into

Straight-Flight Stairs 1 9 5

Stair stringers need to be fastened securely to the header joist.

the joist. Then nail the strap to the joist. Pull up the second stringer and nail it to the first block and to the joist. Finish by nailing in the second block and the third stringer.

Another quick method of installing stringers is with 2x8 or 2xlO joist hangers (drawing B). Just make a horizontal cut about lYz in. deep on the back of the stringer to house the bottom of the hanger. Nail the hanger to the stringer, place the stringer on the line below the landing and nail the hanger into the header joists.

A third method (drawing C) is to use a hanger­ board, which is a piece of %-in. or %-in. plywood about 15 in. wide by the width of the stairs (36 in. in our example). Nail the hangerboard to the face of the joists, flush with the landing. It should hang down no lower than the bottom of the stringer, so that it won't interfere with drywall on the under­ side of the stairs. Then draw a line across the hanger­ board one riser height below the landing. Secure the stringers with nails driven through the back of the hangerboard.

Three Ways to Install Stringers

Hang stringers to this line.

A. Using metal straps

Blocking

B. Using joist hangers

1%-in. saw cut

Saw cut allows you to insert a 2xBjoist hanger.

C. Using a

hangerboard

Hangerboard nailed to header joists and stringers

1 9 6 Building Stairs

A 2x4 kicker at the bottom of the stairshelps to hold the stringers in place.

With the stringers nailed on at the top, cut a 2x4 kicker for the bottom the width of the stairs. Slip it into the notches on the front end of the stringers and fasten it to the floor. Then toenail the stringers to the kicker.

Drywall and skirtboards

If one or both sides of the stairs is a wall, you need to make some adjustments before hanging the stringers. By holding the stringer 1 Yzin. from the wall framing, you will leave plenty of room for Yz-in.

drywall and a Ix skirtboard (or /I finish stringer") to slip in between. If the space under the stairs needs

to be drywalled, you can slip the drywall all the way through to the bottom plate.

The skirtboard serves the same function as base­ board: It protects the drywall and covers the joint where stairs and wall meet. The skirtboard can be built like a reverse stringer that can fit down on top of the stairs. But it is much quicker to hold the first stringer off the wall enough to let the board slip down between it and the drywall. Hold the skirt­ board up above the nose about 3 in. to 4 in. and mea­ sure its length down the stringer. Make a plumb cut at the top of the Ix skirtboard and a level cut at the bottom, and then slip it down alongside the stringer after the drywall has been installed. Any remaining

Adjusting for Drywall and Skirtboard

Drywall

Skirtboard

Stringer

Installing the stringer 1);2 in. fromthe rough wall leaves room for drywall and a 1x skirtboard to slipinbehind.

Straight-Flight Stairs 1 9 7

Pony Wall

to 48 in.

Width of

stairs

gap between the stairs and the drywall or skirtboard will be covered with carpet or finish treads and risers

later on.

It's a good idea to build a pony wall between the walls that enclose most staircases. A pony wall is a

short wall that closes off the inaccessible area at the bottom of the stairs and helps to support the

stringers at midspan (see the drawing above). Mea­ sure back about 3 ft. or 4 ft. from where the stairs

and floor meet and build the pony wall under the stringers, again holding it away from the walls so

that the drywall can slip past.

Installing Treads and Risers

A backcut can be

maintained on the topriser
bynailing a txt	behind it

Riser

Sheathing

A small gap between tread and riser helps eliminate squeaks.

1Y4	-in.		/

overhang -----

(max.)

Nosing

Cutting and installing risers and treads

If the stairs are going to be covered with carpet, they

can be sheathed with material left over from the floors (at least !Va-in. stock for risers and %-in. stock for treads). Rip the stock along the long edge on a table saw, or use your circular saw (carefully follow­ ing a chalkline or using a guide). Both the risers and the treads will be easier to install if they are ripped

slightly narrower than the actual rise or run (Yll in. or so). Rough risers and treads don't need to fit to­

gether perfectly, especially on the backside. In fact, one potential source of stair squeaks can be elimi­

nated if the treads and risers are prevented from touching and rubbing against each other.

Normally the treads and risers will be the same width as the stairs, but if one side of the stairway is going to be left open you may want to let them hang over so the drywall can butt up under them.

Nosing, a part of the tread that protrudes beyond the face of the riser, is generally not used when stairs

are to be carpeted, but if it is desired, rip the treads accordingly. Most codes allow treads to hang over

up to 1% in.

Hardwood boards can be cut and secured direct­ ly to the stringers or to the rough-sheathed risers

and treads. Many builders like to rough-sheathe their stairs and then apply the finish boards when

the house is almost complete.

1 9 8 Building Stairs