How's an alternating tread stairway for basement access?
June 5, 2020 5:55 AM   Subscribe

We need to change the access to our unconditioned basement. In the future, when people (plumbers, electricians, etc.) need to quote jobs and to use it, we don't want the access to be off-putting, including if they need to carry heavy, bulky things. Are alternating tread stairs a good solution in our situation?

We had an outdoor bulkhead that will be replaced by indoor access to the basement. The available space is too constrained for a typical stairway. The contractor who's building it talked with us about some options for making it easily navigable enough for anyone who needs to go up and down, including if they're carrying heavy and bulky things. (E.g., We have a giant water heater that presumably will need replacing someday...) We gave the contractor the go-ahead to get the job underway and finalize the details of the stairway as he opened everything up and had a better look.

He's created a new hatch in the living room floor and exposed the joists in the basement. He considered a stairway with 9.5" risers, 8" treads, and a turn at the bottom. But unfortunately, that still puts you one step too high when you'd have to duck under a joist as you make that turn -- it would be an excessively low duck.

At this point, there are three apparent options...
1. Make a straight ladder/steep stair with handrail. I'm virtually sure it would be steep enough that you'd have to go down backwards, which isn't what we hoped for when thinking about access that wouldn't be off-putting.
2. Make an alternating tread stair. I think that would end up being a good solution for our own use, since we'd get used to it, and it's the idea that the contractor favors. But would it be off-putting for workers because it's unfamiliar?
3. Go back to a good idea that the contractor had originally had, but decided not to pursue, and that now would cost extra and be a hack. A main beam is what constrains the length of the stairway. The hatch that's been created runs from the side of that beam towards the wall. The first step could be onto the top of that beam instead. That would gain the one step needed so that, at the bottom, you wouldn't have to duck so much. The contractor decided against that when he opened up the area and saw that a joist bisects that beam. So, the top step would have a joist in the middle, and you'd have to step on one side or the other of it. But that would be true of an alternating stair, also, so in itself it wouldn't be a deal-killer. What might be is that now it would mean a second part of the hatch that's already been built, and the extra time and cost to create it.

I'll start without dimensions and photos, because my main question isn't for further design problem-solving, but simply: Is an alternating tread stairway a good solution, or is it inherently off-putting for workers who encounter it? But I'll gather the dimensions and photos, so I can add them later if it seems like that would be helpful after all.
posted by daisyace to Home & Garden (21 answers total) 2 users marked this as a favorite
So, the top step would have a joist in the middle, and you'd have to step on one side or the other of it.

That sounds like a trip hazard. Unless I am misunderstanding the description, I do not like this option.

Realistically, you will have workers coming in maybe once every year, or even once every few years, right? So you should base your decision off of what is safe and convenient for you on a daily basis, and expect the workers to be able to deal with it on the rare occasion that they are there.

Of your options, the alternating tread staircase seems like the best and safest choice. You keep the headroom, there is no unusual tripping hazard or need to back down, and you will likely meet code -- I'm not sure your other choices would pass inspection in many places.
posted by Dip Flash at 6:10 AM on June 5, 2020

Dip Flash, that makes sense, and also makes me realize that I should clarify that since the basement is unconditioned, not living space, I think a to-code stairway and inspection isn't required. E.g., even a ladder would be allowed, if that weren't objectionable for us. Worker access is probably the most common use case -- we'll go down there if a circuit trips or something, but not frequently. (And an alternating tread stair also forces you to step on just one side or the other, though it does so all the way down, not just on the top step.)
posted by daisyace at 6:24 AM on June 5, 2020

You could also maybe reduce the hazards involved in getting heavy things in and out of the basement by designing a heavy-load hoisting point into the ceiling, as close to directly above the hatchway as your ceiling beams allow.
posted by flabdablet at 6:32 AM on June 5, 2020

I'll just chime in to say that another person who might need to get down there is a firefighter, so a built-in trip hazard could cost someone his life - which is one of the primary reasons we have building and fire codes. A quick google shows that the places that do allow them limit their use to lofts or attics that would otherwise use a ladder. The fact that there's heating and electric equipment is down there would put it off the table for me.
posted by bonobothegreat at 7:08 AM on June 5, 2020 [3 favorites]

Ok, I've added photos and dimensions here.
posted by daisyace at 8:03 AM on June 5, 2020

The legality varies quite a bit so I'll talk about the situation here, YMMV.

Here unconditioned space doesn't have different rules for stairs.

Your contractor's proposed stairs are already not code legal in Canada and IME even maximum steepness stairs are a hazard.

Alternate tread stairs aren't permitted in Canada. They are great for people who use stairs regularly but are a significant hazard over regular stairs for occasional users.

Ladders are legal. And a properly constructed, angled1 fixed ladder is safer than really steep stairs because you go down backwards. A trip generally moves you towards the ladder instead of away from the stairs. Worst case you sort of slide down the ladder; worst case on a steep set of stairs is you fall and rotate landing on your head.

As an electrician I'd much rather move material and tools up/down a ladder space than crazy steep set of stairs or some non standard layout. I can jut lower things with a rope and devote all my attention to navigating the ladder.

The code legalness of stairs is important two ways: Generally it creates less of a hassle during sales. It also protects against lawsuits.

Also I wouldn't angle the ladder towards the wall. That creates a narrow space that is tough to navigate. Put the ladder at the wall side of the hatch, have the hatch open towards the heater, you can have a grab bar/hand rail attached to the wall upstairs. The railing can be removable.

TL;DR: if you aren't going down there every day put in an angled ladder.

[1] the ladder should be angled no steeper than a step ladder. 4:1 or a bit shallower.
posted by Mitheral at 8:14 AM on June 5, 2020 [13 favorites]

Ladder, definitely. Greatly reduced risk of injury.

Most (not all, but most) of the alternating-tread stairways I've personally encountered had to be navigated like a ladder anyway, so they really offered nothing but danger and a cooler visual appearance. If you want to be mega-super-friendly to future contractors, you could buy a confined space hoist and stash it somewhere out of the way so that it's available on the rare occasions you need it.

You may want to consider making the ladder removable (eg: attach it to a steel plate with bolts), so that if you really are loading some big chunk of plumbing/HVAC in and out of the hatch you can get the ladder out of the way for maximum ease of lift, but that's starting to get pretty fancy for occasional use.
posted by aramaic at 9:13 AM on June 5, 2020 [2 favorites]

You might also want to check that the beast of a heater isn't too wide to fit through that hatch before committing to making that your only basement access.
posted by flabdablet at 9:26 AM on June 5, 2020 [4 favorites]

I would go with a ladder or a stairway with a low duck over an alternating tread situation, personally. Both seem more usable.
posted by amaire at 11:05 AM on June 5, 2020

I'm gonna echo the chorus, especially after having seen your pics, and say that a ladder is best. It would be great if it could fold out of the way for hauling things up and it would be great if it was securely attached at the top. There are homes in my area where the utility systems are reached with a vertical ladder through a floor hatch in a closet. They are pretty terrible. Yours looks better.
posted by amanda at 11:08 AM on June 5, 2020 [1 favorite]

Consensus indicates eliminating options 2 & 3, got it. To amaire's point, and since we really didn't want a ladder we'd have to back down, should we revisit the option I mentioned right before the numbered ones: a stairway that turns at the bottom, but where you have to duck down as you make that turn? I'm figuring it might come out to only ~55-60" high at the front edge of the second-to-last stair, right before you step down another 8-9.5", and then to the ground. Obviously not great. Worth considering anyway if it makes a stairway possible instead of a ladder, or no?

(And flabdalet, yup, the heater width does fit.)
posted by daisyace at 11:20 AM on June 5, 2020

Oh -- and if it's not worth considering at that height, but my calculation's wrong, or the contractor can find a way to get a few more inches of head-clearance, then what's the lowest duck when you WOULD say it's worth considering?
posted by daisyace at 11:33 AM on June 5, 2020

I'm not sure if regular code applies to a condition where you'd legally be able to install a ladder or alternating tread device (or even a 8" tread/9.5" riser stair) in the first place, but normally you'd need 80" clearance for the length of a regular stair.
posted by LionIndex at 11:34 AM on June 5, 2020

80" would be a lot more than in the basement itself. You already have to duck down there if you're above-average height. I probably should have called it a crawlspace, which is what they considered it when they insulated it. The bottom of the beam is maybe 67"-ish high.
posted by daisyace at 11:43 AM on June 5, 2020 [1 favorite]

Just out of curiosity, what is it about backing down a ladder than makes risking a faceplant off a steep staircase preferable?
posted by flabdablet at 12:26 PM on June 5, 2020 [1 favorite]

Regardless of how you plan to access the basement, you might want to consider adding some sort of heavy duty reinforcement in the ceiling above the hatch. That way, if you need to lift something out of the basement, you don't have to jury rig something.
posted by Marky at 1:39 PM on June 5, 2020

what is it about backing down a ladder than makes risking a faceplant off a steep staircase preferable?

As you rightly imply, it’s not, so I eliminated options 2 & 3 as everyone advised. There’s some amount steep above which a ladder is preferable, but below which stairs are, right? I think we could keep stairs on the acceptable side of that line if the stairs turn, but then you’d have to duck under the joist. So the choice now is between that vs. backing down a ladder.

I think with some steep stairs/ships ladders (and maybe some alternating stairs), people can choose to go down them backwards or forwards. But unless ours turn under the joist, they’ll be too steep for that and we’ll have to go backwards. Which isn’t the end of the world, but isn’t as desirable as an acceptably pitched stairway.
posted by daisyace at 2:07 PM on June 5, 2020

I think you need to adapt an attic ladder to this application.
posted by Thorzdad at 2:45 AM on June 6, 2020

isn’t the end of the world, but isn’t as desirable as an acceptably pitched stairway

Given the space constraints that apply and the intent to make getting bulky things in and out of there less fraught, if your house were my house I'd consider a ladder I could hoist stuff up the face of, or possibly even quickly unbolt altogether, much more desirable than a permanent bulky lumpy obstacle in the form of a staircase. So I'm still curious as to why, in your mind, it isn't.
posted by flabdablet at 5:27 AM on June 6, 2020

So I'm still curious as to why, in your mind, it isn't.

Only for the usual reasons that stairs are preferable when they fit (i.e., easier to go forwards than backwards, more accustomed use, easier if you've got something in your hands...). Nothing specific to this space. Moving something massive is the toughest use case that we want to ensure isn't unnecessarily tough, but it's not the one-and-only, defining use case.
posted by daisyace at 8:19 AM on June 6, 2020

Fair enough.

Still, if that were my house, and I were semi-regularly carrying smallish things up and down through the basement hatch, I'd be inclined to install the facilities required for handling enormous things and then make a game of using them for the tiniest :-)
posted by flabdablet at 10:52 PM on June 7, 2020

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