Stage flooring

[edark]

Hi all,

we are replacing the flooring of our stage. Its currently tongue & grove boarding. Any advice on what is the best structure / materials to use?

The floor is on wooden joists, with an understage area below, so any structure must be fire resistant.

 

I have heard that some theatres have a system whereby there is a main floor covering with an additional layer of boards on top to take the battering, spiking, nailing and drilling and general abuse that stages are prone to taking. The top boarding is in sections that can be replaced easily and not too expensively.

Is this common practice? If so, what type of wood is usually used? MDF, Ply, Chipboard? and what thickness?

 

We are a multifunctional venues with a variety of acts, bands, ballet, dance, presentations, touring shows etc etc. What kind of weight should it be able to take? is there any kind of standard safe working load for a stage?

 

 

Your help is greatly appreciated.

[robloxley]

18mm plywood with 4mm MDF on top?

As for fireproofing this will probably down to the plasterboard lining below the joints, forming the ceiling of the understage.

[edark]

Is this a standard setup? 4mm sounds a bit thin?

[andy_s]

18+4=22mm, with the top 4mm replaceable - much much cheaper than replacing 22mm ply.... however it won't take a great depth of nail or screwhole without piercing the underneath, so yes, if you want to completely protect the underlayer, you need a much thicker top sheet. Personally, I wouldn't think this was necessary.

 

the other factor which might affect your decision is of course the gap between joists - Steeldeck uses metal joists to support the floor every 600mm, and their figure for 18mm tops (depending on the grade of the plywood) is 7.5kN per metre squared, or 2.25 tonnes on an 8' x 4' deck (according to maltbury's figures)

[erroneousblack]

6mm hardboard, as a top layer. Takes a lot of stick and easily replaced. Don't touch MDF with a barge pole, might be cheap but is regarded by many as the new asbestos.

[andy_s]

6mm hardboard, as a top layer. Takes a lot of stick and easily replaced. Don't touch MDF with a barge pole, might be cheap but is regarded by many as the new asbestos.

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this is true - there are recognized health and safety concerns about the dust caused by cutting operations - the risk assesment for this particular use could be low, as the activity "cutting sheets to size" would be infrequent, and the cutting could be done off site in a workshop with extraction equipment etc. Once the mdf is down and sealed, the noxious dust is not problematic until you start cutting it again. If using hardboard, use oil-tempered boards to avoid "bubbling" and warping.

[edark]

The top layer is very unlikely to be cut between renewals, except for being screwed into occasionaly. so besides the possible health risks involved with MDF, any ideas which actually makes a better floor covering? Is hard board prone to warping and bubbling?

 

thank you everyone for your help so far :(

[TomLyall]

Is hard board prone to warping and bubbling?

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Previous post... :(

 

If using hardboard, use oil-tempered boards to avoid "bubbling" and warping.

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[andy_s]

hardboard gives you a choice of surfaces, as there is a shiny side and a rough side. that's a once only choice of course, but it's a choice you don't get with mdf!

 

I think most good timber suppliers can supply oil-tempered boards, there is another way of getting it to lie flat - paint both sides before laying it. The other thing to remember with hardboard is that cut edges can swell up - to avoid this, smooth the edge with a bit of sandpaper, then seal the cut by painting a bit of PVA along it (says the hardboard king at the desk next to mine!!

[Joker7]

Question :

 

Would one still damp down oil-tempered boards 24 hours before laying ?

 

Brush water over the rough side of each panel. Leave for at least 24 hours to allow the boards to adjust to the humidity of the room. This will cause the boards to expand a little. When they dry out, they will pull tight and lay flat.

 

I would ,but would you do ?

 

Regards

Chris

[paulears]

There is one thing about MDF that doesn't get talked about much - the urea-formaldehyde used in the pressing process gets released into the air and can make eyes itchy and watery. It tends to go away once the surface has been sealed - but some people are quite sensitive to it - laying a whole stage floor means a lot of surface area open to air. I build a lot of project studios and tend to use MDF as one of the wall and ceiling layers. Depending on the design the inside faces could be plasterboard or MDF when there's a good chance of damage. If it's a fairly small area walking in when the doors have been shut over the weekend when first built, can really make you gag. I'm assuming that while we wear masks and goggles when cutting for dust inhlation reasons - it's the same chemical present in the air once the dust stage has passed?

[edark]

Thank you everyone for your much appreciated help.

 

I have now specified 18mm ply with 6mm oil-tempered hardboard top covering. The fire-proofing will, as suggested, be addressed by the plasterboard of the ceeling underneath.

Also, before laying, the hardboard edges will be sanded and sealed with PVA to help prevent swelling.

 

The hardboard will be fixed with counter-sunk brass screws.

 

Thanks again for all your help and hope this topic will help others in the future too.

;)

[edark]

The new floor has now been laid and looks lovely.