1st time building finshed stairs questions

[Frank Di Sessa]

I am building my first set of stairs and need some help with some general questions. I already have a rough set of stairs that go from the main floor down to the basement with a 135deg turn after 2steps down and then two winders (67.5degrees) and then 9 straight steps to the basement floor.
Stairs are in a stair well finished with drywall on each side with exposed studs on both sides below the stringer level. I want to add a 2"x4" on the lower outside of each stringer to fasten to the studs on either side of the stair well. I then want to slide a 3/4" baltic birch plywood skirt board between the drywall and the stringers that I will secure to the drywall with brads. The stair treads will be 1-1/4" cherry and the risers will be 3/4" baltic birch plywood.

Q1.) What is the best way to attach the stringers to the stair well studs? I was thinking of using 2" brads to attach 2"x4" to the bottom of the stringers temporarily and then drive two 5-1/4" x 5/16" GRK RSS screws thru that assembly into each of the wall studs in the stair well to secure the stairs. I don't own a nailer and already have the 5" screws on hand.

Q2.) I want to protect the bottom of the stringer from water damage so wanted some ideas on how to do that. So I thought about using a couple of pieces of treated 2"x4"s that I would attach to the basement cement floor with three TAPcons (2-1/2") each and then cut the stringer by 1-1/2" to accommodate the height difference. then I would attach the stringers to the treated 2"x4"s using right angle brackets (Simpson, etc) to secure the stringers to the ground.

Q3.) Should I glue the skirt board to the wall or will the brads be enough to hold it in place? I just don't want those skirt boards coming off the wall in time.

Q4.) How should I do the support for the winder steps on the wide side? I was thinking of using regular stringer on the narrow side and then use two pieces of 2"x12" cut down to stair unit height and unit run length that attach directly to the wall studs spaced with 2"x4"s at the bottom to keep the same offset from the wall studs.

Please let me know if you need more clarification.

Thanks,
Frank

[Jim Dwight]

I can't picture your stairs but I will add a couple comments from my experience building a set of stairs for my house. When I tore out the badly framed original set, I noticed whoever put them in (suspect the previous home owner based upon the grossly wrong rises) fastened the stringers to the studs with a 2x4 laid flat in between. He spaced the stringers off the studs by 1.5 inches with the 2x4. That gives plenty of space to slide a skirt board in without a need to cut it to follow the stairs. I just butted the treads and risers to the skirt. I dado'd the back end of each tread for the riser to fit into. Makes a secure connection. My 3 stringers were cut from 2x12s, not 2x10s like the original stairs. I don't think there is enough meat left in a 2x10 after the notches are cut.

I fastened the stringers to the studs through the 2x4 with framing nails. Framing nails flat spacer stud to studs then skirt to flat spacer stud. I do not see why you could not use long structurally rated screws. I don't think brads will hold much of anything, however. You could try tacking them with them I guess. I would definitely have pressure treated touching concrete. Easiest would be to screw a pressure treated 2x4 or 2x6 from the bottom up into the stringers before they are installed and then tapcon the pressure treated to the floor after the stringers are fastened in place. Remember the stringer already has to be shorter at the bottom by the thickness of the treads. So if you put a 2x on the bottom you have to reduce it for both. Brad nails are inadequate for framing connections but fine for finish work like a skirt board. I put the skirt over top of the drywall, don't know what you are thinking.

[Rob Sack]

I have built several sets of stairs, both interior and exterior. First of all, I don't use nails for attaching stringers, I use structural screws. If it's a situation where I think the structural screw heads would be too unsightly, I use high quality trim head screws. GRK has a large selection of both, as do other manufacturers. I will only use nails for non-structural trim, and even trim head screws sometimes if it's paint grade trim. As far as having the bottom of the stringer coming in contact with concrete or any exterior surface, I glue and screw a piece of composite decking to the bottom of the stringer using something water proof like Titebond III, construction adhesive, or even silicone along with stainless steel screws.

[Cameron Wood]

I'll just add that when the treads and risers are scribed to the skirt boards, it's important that they be tightly fastened to the wall.

If not, the treads can wedge them over,, creating a gap at the treads already installed below.

Since the skirt will change angle at the winders, there needs to be good backing for the point made above and to keep the joints from opening up. I would use trim head screws and shims to keep the skirts straight and plumb.

Brads don't really belong in the mix- 14 or 15g finish nails do.

Since the stair is mainly supported from the walls, there doesn't need to be that much at the concrete floor. Traditionally, the bottom of the stringers would be notched around a 2x4 kicker fastened to the floor. Some sturdy stick-on flashing should be enough to protect the stringer ends from the concrete.

[Thomas McCurnin]

By winders, if you mean landings, usually the lower landing is supported by 4x4s nailed or tapconed to the floor.

The stringers can be made from PT lumber and covered with a skirt to protect the stringer from water damage. I think I would want the stringers to be one piece as opposed to cobbling them to a base and using mechanical fasteners, but your idea isn't so bad.

[Frank Di Sessa]

I can't picture your stairs but I will add a couple comments from my experience building a set of stairs for my house. When I tore out the badly framed original set, I noticed whoever put them in (suspect the previous home owner based upon the grossly wrong rises) fastened the stringers to the studs with a 2x4 laid flat in between. He spaced the stringers off the studs by 1.5 inches with the 2x4. That gives plenty of space to slide a skirt board in without a need to cut it to follow the stairs. I just butted the treads and risers to the skirt. I dado'd the back end of each tread for the riser to fit into. Makes a secure connection. My 3 stringers were cut from 2x12s, not 2x10s like the original stairs. I don't think there is enough meat left in a 2x10 after the notches are cut.

I fastened the stringers to the studs through the 2x4 with framing nails. Framing nails flat spacer stud to studs then skirt to flat spacer stud. I do not see why you could not use long structurally rated screws. I don't think brads will hold much of anything, however. You could try tacking them with them I guess. I would definitely have pressure treated touching concrete. Easiest would be to screw a pressure treated 2x4 or 2x6 from the bottom up into the stringers before they are installed and then tapcon the pressure treated to the floor after the stringers are fastened in place. Remember the stringer already has to be shorter at the bottom by the thickness of the treads. So if you put a 2x on the bottom you have to reduce it for both. Brad nails are inadequate for framing connections but fine for finish work like a skirt board. I put the skirt over top of the drywall, don't know what you are thinking.

Hi Jim, Thanks for your response. Not sure about screwing the 2x4s to the bottom of the stringers from the bottom up and still keeping everything aligned properly! Yes. Skirt is on the drywall. I was thinking of using brads just to keep 2x4 on the stringer temporarily as it will be driven in by structural screws at the studs when I put the stingers up.

[Frank Di Sessa]

Thanks for your response. I agree with your comments about using the trim head screws to hold connections at the miter in the skirt. Is it OK to use brads or 15gauge (air gun) nails for the rest of the skirt board?

[Kevin Jenness]

A plan drawing would help. Be sure that your stair will be passed by the local inspector if that is an issue. Winders are tricky. Codes typically call for 6" minimum tread width at the inside stringer and a consistent width along the walking line 12" to 15" outside the stringer.

[Jim Dwight]

There should be zero stress on the skirt board at least there is the way I did it so I don't think it matters much what you put it up with. The stringers support the treads and the riser. The skirt board is part of the trim carpentry and I use mostly 18 gauge brad nails on trim. If the 18 gauge pins hole the 2x4 spacer in place OK and you screw through to the studs with good structural screws then the pin nails would be OK. But be careful putting the stringers in position, you could knock the 2x4 out of position. I would use at least a 16 gauge nail. I think HF pneumatic nailers work OK and they are really cheap. If you are using the 18 gauge because you don't have a bigger nailer I would just get a HF 16. Should be $20-30. Even a 15 gauge will be under $100. If you ever do window stools or hardwood flooring (the first rows before the flooring nailer will work) you will have to have at least a 16 gauge.

I like trim head screws too and used a bunch on both the staircase and the posts and railing. They hold well and the holes are easy to make unobtrusive with the right color wax crayon.

[Jim Dwight]

The skirt board is different if the end or ends of the staircase are open - do not go into a wall. Part of my staircase is that way and I mitered the skirt board and the risers to get a good fit. But the risers are still supported by the stringers, not the skirt board. The stringers are supported by the floor and in my case a framed landing.

[Tom M King]

I didn't read the whole thing but will just add this for a first time stair builder. The most common mistake made by new stair builders is not to allow for the tread thickness on the first step. They cut all the risers the same on the stringers which ends up with a taller first step in the finished stairs. Every step needs to be the same rise, and a straight edge should be able to be laid where it hits all the step noses as well as at the top landing.

The easiest way to make perfectly fitting steps is with housed stringers. They might seem like more trouble, but they really aren't. These were some I built in 1991. In the picture they are 23 years old. I like to buy boards wide enough so the parts are not joined up pieces.

[Bradley Gray]

+1 on housed treads. There is an excellent article in an early FWW. Squeak free for decades.

[Cameron Wood]

Spiral stairs are cool, have you considered that?

(since we're getting close to bringing up almost every non-applicable stair issue...)

[Frank Di Sessa]

Wanted to do the housed stringers initially, but did a cost analysis and it turned out to be more expensive including the winder portion (Wider stringers to assemble). But I agree would be faster to build using a router and everything would be square right out of the workshop.

I am now looking at how to fasten the risers and treads. I think I will tack on the risers with PL premium and do some pocket holes on top back of the risers to drive into the tread bottom front. I will attach the tread with some PL premium (will need some way to keep it in place - maybe someone standing on the tread) and use some pocket screws to hold them in place from the bottom riser and the back riser thru the back of the tread. I think this is probably the scariest part as the glue is a mess and things tend to slide around in the wrong way some times.

[Kevin Jenness]

The construction adhesive will minimize squeaks. If you don't mind a few face nails in the treads you can pin them in place with an 18 ga nailer, then drive screws through the risers into the back of the treads and pocket screws into the underside. You can use pocket screws through the stringers as well. I would use PL on all those joints, but sparingly where it can ooze visibly. You will want some kind of adjustable template to get the length and angles of the treads and risers correct. This is where housed stringers have an advantage as the tread and riser lengths can be looser. You can also install the housed stringers and wedge the treads and risers in place one by one. I know you have rejected that approach but it is easier to achieve good fits. Here's a thread showing a housed winder staircase. https://sawmillcreek.org/showthread....ancing-winders