Finishing MDF

[Rich Torino]

A friend of mine is building a home theatre in the basement playroom of his home. The research he did says that using MDF on the walls will creates superior acoustics in the room. (I have no idea if its true or flase) The question is can/how do you the finish nail holes and seams in the MDF walls? Can it be taped like drywall or is there a "better way"? He plans on paining the wall when he is finished. Any help or suggestions will be appreciated..
Thanks
Rich in Florida

[Steve Cox]

Nail or screw holes, Bondo is great stuff. Drywall mud would probably work and I don't see why you couldn't tape it like drywall as long as you'll eventually have some texture to cover it. BTW what is under the MDF? If I'm not mistaken (and I very well could be ) code requires the use of drywall for fire protection. Something to think about.

[Rich Torino]

Thanks Steve.... didn't think about the fire protection.. I'll have to look int that.

[John Hemenway]

A new building at my workplace (Community College) has MDF walls in the lobby. Finish is poly. Looks pretty good till you walk up close. My first reaction was, OMG! that's MDF. I don't remember how they dealt w/ the seams. If you want I could take a walk over there this afternoon and take a couple of pics.

[Lars Thomas]

I know just enough to be dangerous here - I can't envision a scenario where MDF walls make an acoustically superior listening environment. MDF is denser then traditional drywall – which would lead to more reverberation of sound waves. In most cases, you want jus the sound coming from the speakers, not bouncing around the room. This is why theaters typically have fabric covered walls (they are also trying to keep the soundtrack from the latest action movie out of the theater next door playing a chick-flick – similar in many ways to what your friend is trying to do

But to answer your question, Put it up with finish nails and fill with drywall mud (watch the water content – especially near the edges). As for the seams, I suppose I would run a bead of latex caulk in between each sheet while it was being hung. Then wipe up any caulk that squeezed out. If he wants to put MDF on the ceiling (crazy), be sure to use some big honking screws. For the sake of ‘decorating’ the MDF, your buddy could spray it with a product like tuff-hide (self-leveling – high solids content)

Is your friend trying to keep sound in the room, or are they trying to keep it out? In either event, run two beads of a quality caulk under the sill plate. Also caulk around any openings (outlets, plumbing etc . . . ) Installing drywall (or MDF if you really want to go that route) on some J-Channel which will get the drywall off the studs to reduce sound transmission (do the same for the ceiling). Insulate the wall cavity with as much insulation as it will hold – even interior walls. Or, more aggressively, your buddy can build what equates to a room with-in-a-room (ie, does not share any walls with any other part of the structure.

[Keith Christopher]

To get an even drywall look, apply drywall "mud" to it. Sand it nicely and you'll get an AWESOME painted finish. Of course always keep fire and building codes in mind.

[Todd Burch]

Put MDF up with screws, then 1/4" sheetrock over that.

[Jay Knoll]

I have used a product called "Half Time" you can get it at auto finishers supply store. Sets up in 20 min or so, sands extremely well.

[Rich Torino]

Thanks everyone for all the input... I'll pass the info over to my friend...
I think headphones would be an easier solution ..
Rich in Fl

[Matthew Poeller]

MDF is a superior product for speaker enclosures. In fact many of the best speakers in the world use 1.5 in thick MDF for there enclosures. This makes them very heavy but article that I have read from places like Old Colony Sound Lab and such tout it as the best material.

That being said I am not sure that you would want to use that for the walls of the theatre room. I agree that I think that there would be wayyy to much reverberation for this to sound decent. Basically it would be like sitting in the box of the speaker.