Construction of sprung dance floor?

[RickH]

I dance 3 or 4 nights a week on the Willowbrook Ballroom dance floor. It is a 6200 square foot bare maple floor constructed in the early

1920's. It has had dancers on it continuously since then dancing to all the great swing bands of the 20's through 50's and continuing to this day.

It is an amazing floor, it is mechanically sprung like no other floor I have ever been on. It has a wonderful thump, smoothness and bounce that is unheard of in these days of banquet halls where some dumb-ass restaurant owner simply applies some prefinished flooring to concrete and calls it a dance floor.

The Willowbrook floor is referenced in this wiki article about floor construction, but is not detailed enough for my project:

My dream is to install this same kind of floor in a building I own. I would love to see exactly how the Willowbrook is constructed, but that wont be possible. I've danced on sprung floors over foam, and it is simply terrrible, like landing on sand, there is cushion but no return in energy, foam sucks. The Willowbrook floor is somehow sprung using wood.

I will finish the with 1 inch T&G bare maple just like Willowbrook. Of course over 90 years of dancers feet does more amazing things to bare maple, which can never be replicated in ones lifetime.

Does anyone here have any knowledge on how the amazing dance floors of early the 1920's were constructed? In terms of the under structure? Possibly any old-timers who installed basketball courts in the 1950's, might be similar?

If you have knowledge like this, please share this lost art in the wiki article before you die.

[RickH]

Additionally, I get the feeling that the Willowbrook has a 3 layer basketweave spring system. One cannot detect any "studs" or solid spots anywhere, all is good and springy.

Here is a diagram of a triple basketweave spring system:

Based on this diagram what species/size would you use for the basketweave battens?

Also assuming 3/4 inch maple on top, would 1/2 inch plywood be a good load distribution layer (underlayment)? My fear is that 3/4 inch plywood would negate the effect of the basket springs by being too stiff.

[RickH]

Well here is an amazing time-lapse video of what I think I need to do, (you gotta see this video if you are a carpenter its really cool):

They actually go with a 4 layer basketweave, with the last batten weave getting fiberglass batting to give the floor a nicer sound tone and hide any rattles i guess.

The underlayment appears to be thin as I hoped so to take advantage of the basket structure, maybe 5/8 or 1/2 ply one layer.

It would be my guess that they shoot a screw through each intersection of the basket batens because I think nails would pull out and cause the battens to "slap", is this a correct assumption? The first layer of batens appears to be sitting on small hard rubber pads, maybe 1/8 to 1/4 inch thick neoprene squares?

I might be answering all my own questions, but appreciate any input from pros or others here.

[Jim Elbrecht]

-snip-

Pray tell, Why? You have the time, you are apparently mobile, and you are there 3-4 times a week. You are considering taking on a

*huge* [as in expensive and time consuming] job to do something that will give you pleasure for the rest of your mobile life- and probably will be enjoyed by a few others along the way.

If you can't make an appointment with the groundskeeper or whoever, then you don't have the skills necessary to build, or direct the building of the floor.

-snip-

I'll be waiting to see the photographs and notes you take when you go visit the floor.

Jim

[Robert Neville]

Google is your friend. Search on the terms "sprung dance floor construction"

Wikipedia notes: Early sprung floors often used leaf or coil springs whence the name, these floors tended to bounce, modern floors have suppressed this 'trampoline' effect and so are often called semi-sprung.

[RickH]

I teach ballroom dance thats why. When I retire from my day job I hope to get a studio started in this building rather than having to constantly meet up with students at other locations. That day may come sooner than I planned. Visit what floor? I said I'm on the Willowbrook floor 4 times a week, by "wont be possible" I meant they certainly wont "rip up" a few floor boards for my convenience to see whats under it. Thats why I'm looking for input from someone who has useful advice like someone making basketball courts, etc. Got any useful advice?

[Robert Neville]

One suspects there probably is an access point for inspections or maintenance. Wouldn't hurt to ask the management.

[Jim Elbrecht]

-snip-

Yeah. 4 days a week you work in a building that has exactly what you want in a floor. As far as we know you haven't asked the guy who keeps that floor in shape if he can show you how it is put together. I can't imagine that there are no access points. If you're lucky he will share the same passion for the construction that you do for dance. The worst case scenario- he says 'no'.

Y'know how a picture is worth 1000 words? Looking at the real thing is worth a million.

Jim

[Larry Fishel]

Have you asked if there is access beneath the floor for maintenance? It's hard to imagine that anything that flexes that much could possibly last 80 years without it.

[RickH]

If it is constructed like the video I posted then there would be no inherent access as everything is nailed or screwed together. I know pretty much every square inch and there are no trap doors or anything like that, all is nailed tight. The basement just shows steel I beam joists on 12x12 concrete pylons spaced approx 16 to 20 feet in a grid. The perimeter (for seating) is raised to the floor level and is concrete with tile, so whole dance floor is sunken so to speak with tables surrounding it.

I suspect that it is a 4 layer basket weave of 1x3 douglas fir (or even oak) like the video. Since commercial plywood was in production for about 20 years at the time of construction (1921) I'm assuming the underlayment is also plywood. Top wood is 1 inch bare strip maple laid in a diagonal pattern forming a 6200 square foot "big diamond" on the whole rectangular floor. Based on how 3/4 inch plywood typically feels and sounds on a joist floor, I dont think the underlayment is that thick. This floor gives back a lot of energy and has a very low pitched thump when stomped indicating that the maple skin and underlayment is like one big bass drum; completley unlike flooring on joists which is solid and only rings to the extent it can vibrate joist to joist. The basketweave support allows the whole floor to not have any "hard spots",( like when you can tell where the joists are on a joist floor by knocking). I dont think it can be sprung on real springs as it is so old steel springs could not have lasted 90 years of 400+ patrons doing the lindy each night simultaneously.

It is truly the "Stradivarius" of dance floors in the USA, and I've danced most all the ballrooms that are still left in existence.

[RickH]

Like all finer dance floors it is bare hardwood, no maintenance other than a sweeping and occasional board replacement, which they probably have to custom rip since the strips do not look like any modern standard size. I'll ask the Polish lady that owns the place if there is access.

[Steve Barker]

i assure you, someone, somewhere, knows all about that floor. Check around with the old timers.

[Hell Toupee]

The ballroom may still have the original blueprints and construction paperwork from when it was built. If they don't, I'd next recommend contacting a research library or historical society in your area. A lot of times they have archives containing blueprints and articles about buildings constructed in the surrounding areas. Architects often donate their blueprints and notes to the local research library or historical society when they retire.

Both the research library and historical society in my area have such information available on one heck of a lot of the old buildings in this state - not just commercial buildings, but a good many of the private homes, too. It's always worth checking such resources if you're renovating an old building or looking for information on how to replicate something.

[The Daring Dufas]

I always knew there was something special about some of the floors for dance halls, basketball courts and such but I never knew those floors were THAT special. I'm glad you brought it up, I have now learned something new.

TDD

[RickH]

Great idea, sounds like something I'd actually enjoy doing.

[mm]

That's a big "if", expeciallly regarding access from underneath.

Regardless of how much evidence you have, you should ask. I long ago lost track of the many things I've learned by asking, even when I thought there was no answer.

Are you being shy? People like to be asked and they like to help, especialy if your opening a *small enough* dance studio that won't damage their business but which might provide more customers for their business. And especially if you start off with a few compliments.

[RickH]

I have no problem asking, just thought I'd ask here first as the people there are simply restaurant owners, not carpenters.

In the basement under the main ballroom there is another banquet room with a low ceilng, you can see the underside of the main floor there. It is a steel Ibeam system with smaller steel joists running on 24 inch centers between larger Ibeams that are pocketed into concrete pillars in a grid. Laying on all that appears to be 2x lumber to form the base of main ballroom floor (under the basketweave system). All this underside is sprayed with fireproofing insulation except in a few spots where I can see 2x lumber (might even be 3x lumber). So you cant see much from under side IOW.

This ballroom is also legendary for the "Ressurection Mary" ghost legend BTW.

So this thread gets even more interesting for you ghost lovers... My parents used to drag me along to Willowbrook in the 1950's when they wanted to go dancing and had no baby-sitter, so you might say I've been coming here for over 50 years myself.

Al Capone also hung out at Willowbrook a lot during prohibition and was thought to have an escape tunnel from Willowbrook, I'll find out about that too. Willow Springs is well-known as a place where mobsters dropped dead bodies in the 20's and 30's as it was right down Archer ave. from the city and at the time was considered remote, there are waterways, ponds and filled quarries where autos and bodies were often dumped by Chicago gangsters to this day. Additionally the local govt and police dept in Willow Springs for many years had close ties to the mob.

I doubt that any of the original carpenters are alive but I may be able to do some research locally for things not yet available on the web.

[Jim]

Check this site out here

and also Google "Horse Hair Dance floor" as it was made in the '20's......Hope that was of some help... Jim

[RickH]

Thanks,

The foam underlayment floors are better than a hard floor I guess but nowhere near as good as a real wood sprung floor. Firstly there is no "thud" the foam floors are dead silent useless for soft shoe or tap, and secondly the surface is not bare maple or oak, it is usually a plastic laminate or poly coated wood. Most dancers do not like the foam floors much. Thirdly the foam does not really give back enough, it pads, but doesnt give back, kind of like dancing on sand all give with no bounce regardless of what the brochure says.

Thanks for the horse hair info though, I dont think this is an option but it is nice to know some of those are still in service. I know the Willowbrook is not horse hair as there is a definite ring and thud when stomped.

[sligoNoSPAMjoe]

Check with someone who puts in true professional wood basket ball floors. Today most that I know of use rubber donuts to absorb the shock. I have seen severl designs for the rest.

I put in two for dance studios. For both I used rubber blocks (sorry I forget where I got them) under 3/4 plywood with interlocking parkay wood tile. Between the two they have lasted over 20 years now.