About movie seat construction

[Frank Angel]

We have two screening rooms with about 100 seats in each. Unfortunately, the architect specified sloped floors (nice) but then whoever speced and purchased the seats come to find, they are designed for a flat floor instillation. So now, all the seats are pitched forward. To make matters worse, they are smooth, plastic seats, not upholstered fabric, so given those two elements, one butt tends to want to constantly slide forward. Patrons unconsciously keep using their leg muscles to try to counteract their butts from sliding off the seat. After a two hour movie, people come out with strained muscles and cramps in their legs. I've inspected these seats hoping there was some hidden design that allows the seat legs to be adjusted to match the slope of the floor, but if there is such a mechanism in this design, it certainly is well hidden...or most likely in this case. there simply is no such adjustment.

Which got me thinking, is there a "standard" for sloped floors? That seems pretty unlikely to me and even on the same auditorium floor the slope varies. One theatre I worked in actually had the slope gradually reverse toward the front of the theatre so that a few rows were actually tilted backward. So I am guessing there must be some mechanism in theatre chair design that allows seats to be adjusted to level them regardless of the grade of the slope, yes? Life would be a lot easier for this operator if these seats could indeed be adjusted. Without such an adjustment, it's just slip and slide or just admit defeat and replace all the seats in both screening rooms. Yes, same problem in each room!

[Frank Cox]

Seats come with different degrees of slope built into the side pieces (the part with the armrest and the floor bracket). My seats have a little degree-of-slope number printed under the armrests. The first couple of rows of seats have a different slope than the rest of them so the people in the front couple of rows sit with a slightly greater back tilt than everyone else.

If you used the wrong side pieces for the slope that you have you'd either have people sliding out of the seats or sitting too far back. I suppose the first would be a worse outcome than the second, though.

As far as the actual slope on the floor, when I made my theatre I measured the slope in the existing theatre that I worked in at the time and just used that. The construction guys made stage rafters that extend from the back of the auditorium to about ten feet from the screen; put a couple of layers of plywood on top of that, paint 'er up and call it a sloped floor. I have no idea if it's standard but it's the same slope as the theatre I measured for it.

[Steve Guttag]

Frank is correct, you need the seat standards to be be for the pitch of the floor you have and there is NOT a standard pitch. Localities can have regulations for overall rise over run (think wheelchair patrons having to wheel up some steep slope). Having dished floors is also not too uncommon. I've seen them be greater in the rear and then level off towards the front and, as you described, dish back up in the front. Most large theatres did that so one didn't break their necks looking at that tall screen.

You don't need new chairs but new seat standards...or, see if you can make suitable wedges for them (or perhaps such at thing exists commercially). However, with a wedge, likely, your anchors/studs would be too short in the front now.

[Gordon McLeod]

Wedges do exist Seating Concepts used to be the go to for them. What we do now up here is cut the standard base and re weld them

[Lyle Romer]

Just glue some sandpaper to the seat bottoms. That will stop people from sliding forward! I'm sure it will be very comfortable.

[John Eickhof]

Lyle, wouldnt that wear on the hiney? but, american, and seating concepts used to make wedges that were generally needed when installing used seating in a different auditorium, you can experiment with plywood squares as shims under the front of the seat standard, generally the seat armrest slopes to the back about 3 to 5 degrees for the most comfort, irwin and americans used to have adjustable seat backs for comfort also but the prevalence of rockers has made that a moot point. most ada rules say no more then .75" : foot slope it all depends on the sightlines in the theatre to the screen. I have sold thousands of seats, it is normal practice to furnish the seat manufacturer with final building plans, they do the layout and figure the slopes etc. unless you are installing seats from another theatre...and of course, like Steve said, the anchors may be too short if the shim is very thick, i have done what Gordon suggests, removing the shoe plate and rewelding at correct angle, but it will be a long process and a lot of work...

[Frank Cox]

Lyle, wouldnt that wear on the hiney?

Maybe he has stock in Levi Strauss.

[Frank Angel]

Yah, that's what we were batting about -- wedges on the front foot. The bolts that are sticking out of the floor that go thru the front feet would, like Steve says, be do short if you raise the front legs up, in this case about 2 inches to get the seat level. I am thinking getting threaded stand-offs -- basically a metal cylinder that is has a threaded center all the way thru it. The internal thread allows it to be screwed into the anchor bolt in the cement floor. The standoff screws onto anchor bolt in floor, the seat's foot that has a hole in it that sits thru the floor anchor bolt now sits on the stand-off, raising the seat enough to level it off appropriately. Then finally a bolt screws the foot to the stand-off. Seems like it would work fine, IF the rear foot that it is also screwed to the floor allows itself to be bent, which it will have to do as soon as you lift the front foot the necessary 2 inches. The length of the stand-off is the key to adjusting the seat to be level.

That's a lot of rigmarole to go thru...the other option I am thinking about is simply getting 2x4s, sheering off the floor bolts altogether, sticking the 2x4 under the front legs of the seats and drilling thru the wood and into the cement below, maybe two inches into the cement, then sticking lengths of externally threaded rods thru the wood and into the hole in the cement in the floor that is filled with liquid cement. The cement in the hole hardens, anchoring threaded rod which you cap with a nut, counter sinking it in the 2x4 so the surface of the wood remains sooth & unobstructed. Then it is a simple matter of screwing the front foot of each chair into the 2x4. Eezzy peezzy.

The only question would be if when the cement in the hole in the floor hardens on the threaded rod, will that be strong enough to secure the plank to the floor. That is not the kind of question you want to get the answer to when a whole row of football players all lean back on the seats and the whole row of seats, 2x4 plank and all, rip out of the floor. Maybe the safest thing is to just let their asses slide off the seats like they've always done.

BTW, i am told years ago when they first realized there was a problem, they went out and got seat cushions that tied to the plastic seats. I assumed that would be an interesting solution; when I asked why they stopped using them, they answered with one word. Bedbugs. Although I don't see why that would be any more or less of a potential risk than it is in any theatre with upholstered seats -- just ask the Regal manage of their 42nd street theatre in Times Square that had to be closed for a week do to an infestation. Think about THAT next time you choose to relax in one of the massive recliner seats...hehe

[Frank Cox]

Don't forget that in addition to having those football players leaning back you also have the teenagers in the row behind putting their feet up against the seat backs in front of them and pushing them forward. You have to allow for a lot of pressure on that mounting both forward and back.

[Paul Finn]

Where are the responsible parties in this debacle? Shouldn't the seats be replaced with a correct model for the application instead of trying to devise a patch-it-up fix that may not last? This appears to be a new facility with an architect etc. involved and I would want it done correctly.

Paul Finn

[John Eickhof]

you should consider liabilty when making changes to the seat anchors and hold downs considerable liability rests on the two mounting points, failure could result in injury! what make and model are the seats? i would look into contacting the manufacturer with the correct slope (which appears quite excessive if a 1 5/8 shim would 'level' the seat! and have the proper standards made then switch them out, thus you would retain the designed specs and anchors.

[Randy Stankey]

you should consider liabilty when making changes to the seat anchors and hold downs considerable liability rests on the two mounting points, failure could result in injury!

I had that happen! In the smaller recital hall at Mercyhurst (a stadium style concert hall) there are two seats in the back row at the top of the room that stand by themselves. All the other seats in the house are connected in full rows, as one would expect. As we know, strength comes from every seat in the row sharing the load. No seat actually takes all the weight of the person sitting. It's distributed between "your" chair and the two seats on either side of you.

Since those last two seats don't have any partners to share the load, they don't stand up to the strain of people leaning back and moving around. It wasn't long before the anchor bolts started pulling out of the concrete and the metal flanges that mate with the floor started to get all chowdered up. One of them eventually pulled right out of the floor! The person who was sitting there fell and almost did get hurt! (Mostly just their pride. )

We re-drilled and re-installed the seats but it wasn't long before they pulled out again.

In the end, we just removed those two seats and designated them as wheelchair spaces.

So...Yeah! Do be sure that your seats are properly installed and anchored to the floor according to manufacturer's specs!

It would not have been funny if the person fell out of their chair and tumbled down ten rows of stadium seats!

[Mike Blakesley]

With our last seats, we'd had them installed for a couple months. At the end of the show, this hefty dude reached out and grabbed the seatback in front of him and hauled himself up that way. Wound up snapping some internal parts on the seatback and basically ruining that seat's lean-back feature. We were able to fix it somewhat but it was never quite the same again.

[Gordon McLeod]

There are several variables The grade of concrete and does it have any epoxies mixed in it and the quality of anchor
We use UCAR or Hilti and with a extra long anchor length to give more grip length

[Jesse Crooks]

Where are the responsible parties in this debacle? Shouldn't the seats be replaced with a correct model for the application instead of trying to devise a patch-it-up fix that may not last? This appears to be a new facility with an architect etc. involved and I would want it done correctly.

Paul Finn

Probably too late, but this should have been addressed in the initial installation phase. Whoever specified (or failed to specify) the slope is to blame. The seat manufacturer would have been cognizant of this issue and would have manufactured the seats according to the provided specification.