Help with New stage flooring

[Cob]

Hello,

 

I am hoping to lay a new stage floor in my college theatre. The plan is to use 29, 18ml ply, 8 by 4 sheets with 6.4ml, 8 by 4 sheets of oil tempered hardboard on top attached with countersunk screws. My problem is the current floor in the theatre is concrete and I am wary of glueing and screwing into this in case the floor ever has to come up. My original plan was to attach the 8 by 4 ply sheets together using corrugated pins on the joins and lay horizontally and then harboard on top lay vertically to help hold the ply together. Would this be enough to stop the sub floor moving or would it be better to attach to the concrete using glue/nails

 

 

Any thought appreciated,

 

 

Cheers

[ImagineerTom]

double sided tape?

silicon sealant?

[Brian]

Why do you need to fix it down?

 

In domestic and commercial timber floor installs it's very rare to fix down to any concrete. If the hardboard sheets overlap the ply correctly (ie all edges meet in the middle of the ply sheets) they will act to stop the ply moving apart. You might want to think about a damp-proof membrane on top of the concrete and maybe even something with a bit of 'give' to add warmth to the floor.

 

If you were worried about 500kg+ of timber 'walking' then you could always add a shallow timber lip fixed down to the concrete.

[Cob]

thought I would check but dont think I going to fix it.

 

 

 

Thanks

[Brian]

Just in case you don't know this...

 

8' x 4' sheet material isn't necessarily 8' x 4' big. It's not necessarily 2440mm x 1220mm big either (its quoted metric equivalent). Those are nominal minimum sizes. I've just used a load of 6/9/12/18mm ply for a job and it was bigger by around 3mm in the 4' direction and 6mm in the 8' direction. That soon introduces an error if you don't know about it.

 

You might also want to think about cutting your hardboard down to half-sheets to make future replacement of damaged sheets easier.

[the kid]

A matting between the concrete and the timber is a V good idea. You don't want to have a wobbly board because of a badly skinned floor.

[jonathanhill]

If the existing floor is polished concrete, then laying the boards straight on should be fine, without the need for fixing down. Remember to leave an expansion gap around the edges to allow for the contraction and expansion of the floor. It need only be 10mm.

 

For a posh version, if you have space, it would be nice to lay some thick rubber in strips underneath the 18mm ply to give and element of 'sprung' to the floor.

[Cob]

thanks all the suggestions and help really usefull.

[gyro_gearloose]

What about the chipboard sheets used for boarding out lofts? The edges are machined so that the boards interlock, so if you glue the boards together you'd effectively end up with one giant sheet of wood covering your concrete. It won't move about, and the chipboard has enough give to mould itself to any imperfections in the concrete.

[the kid]

Having a google its called cable floor. I personally would avoid that because of weight when moving it. When I got some 18mm stuff it was 8x2 sheets and weighed a tonne, good for a 100% permanent install, not good if there is a risk you will have to take it up every 6 months.

[kerry davies]

Couple of things I would take into account. Whichever materials have been mentioned are all highly susceptible to damp and water ingress, Brian's membrane suggestion is sound. So would be some form of treatment, especially of the edges. I have had WBP marine ply blow overnight. Lots of it!

 

For the same reason, and it being a college, experience tells me to keep the cleaning contractors well away from it. Mine just ended up like a skating rink but worse can happen.

 

I would start laying from the centre-front rather an edge, but that's just me.

 

I would prefer mats to strips of rubber since strips often roll up when sheets are shuffled round to position. Or if strips then glued down prior to laying sheets.

 

As an aside, I am old and it cracks me up when mixed standards are used and Brian gives a great example; "..3mm in the 4' direction and 6mm in the 8' direction." He is absolutely right but it fries my brain.

[DrV]

As an aside, I am old and it cracks me up when mixed standards are used and Brian gives a great example; "..3mm in the 4' direction and 6mm in the 8' direction." He is absolutely right but it fries my brain.

 

Try aviation then - "Descend 4000 feet and reduce speed 180 knots. You are 9 nautical miles from touchdown and the runway visual range is 800 metres"

 

Right Cedd?

 

Dave

[Dave m]

you could look at biscuit jointers.

 

Aldi/Lidl over here were flogging one for very little number and power tools seem cheap in the USA (where you are?)

 

this would be better than corrugated fixings and it might be better to use a brick bond pattern than a chessboard one