Suggestions for making soundproofed doors

[Anonymous]

Hi,

I've been away from the woodworking scene for a while - and it seems you're all here now. Hi again - hope you're all doing fine!

I've just been given a task to make a set of double doors for a dyno-room (rolling road for motorbikes) which will be at the bottom of my brother's garden - lucky neighbours! He will be soundproofing the walls and ceiling but I've got the task of making the doors.

My plan was to construct the doors from a hardwood frame and MDF facing back and front. I can then sandwich soundproofing insulation in the cavity, and perhaps a membrane inside each MDF sheet. I was going to step the doors on both sides - obviously where the two doors meet, but also on the hinge side to allow two more surfaces to apply a neoprene tape seal to. The frame will need to be stepped as well.

Checking down at my local builders' merchant it seems all you can get hold of is meranti. This is not something I have worked with before, but I have heard it describes as quite a light density timber. If this is the case I am wondering whether a cheaper softwood might be a better option from the soundproofing point of view.

Does anyone have any suggestions about the best materials to use?

Thanks,

Phil (and his brother's neighbours!!)

 

[frank]

hello phil, mdf and rain on the doors dont mix why not use 13mm marine plywood instead, the frames can be made with soft wood ,as long as you treat them before painting they should last a long time .

 

[Anonymous]

Hello Frank - I forgot to mention that these are INTERNAL doors separating the dyno room from the rest of the workshop, so there is no requirement for weatherproofing.

I also forgot to mention that I have to put small viewing windows in each door! I figured I could probably manage quaruple glazing by setting a pane into each side of the frame and into the MDF back and front.

Phil

 

[Anonymous]

Phil

Welecome to the forum

I have used Meranti a lot and it is very light and not particularly hard. I would look elsewhere for a stronger hardwood such as Ash or even use poplar which is surprisingly cheap.

 

[ike]

A softwood frame with sheet or T&G cladding will be the most cost effective materials. Try to minimise internal bracing as this will increase sound transmission between the panel faces. Using hardwood seems rather extravagant since it won't make significantly better soundproofing. Stuff the door cavity with fibre wool, soft foam. or a low density board such as softboard (pinboard). Low density fill is best. The thicker the door section, the better the soundproofing. I'd aim at 50-75mm if possible.

Ike

 

[Philly]

Piquet,
Easiest answer for you is to use firedoor blanks. They are made from edge jointed hardwood, faced with ply. they are solid, and cheap!! Try Howdens Joinery if there is one near you. W
When it comes to soundproofing density wins, so two doors with a gap between them is far superior than trying to manufacture something with insulation inbetween. I know-Ive tried to insulate a drum room at home!
Double up the doors, and seal each door as airtight as possible and you will make a significant reduct in dB's
Hope this helps,
Philly

 

[Guest]

I believe boatbuilders use a lead sandwiched sheet for soundproofing engine compartments.I don't know the cost but I think it is very effective.

 

[ike]

When it comes to soundproofing density wins,

or lack of? :?

 

[mahking51]

Had to do some soundproofing on an engine room for a serious boat in the US some time ago and found that you can get a lead foil backed acoustic foam product that is self adhesive as well. Comes in several thicknesses and grades; has a sort of eggcrate shape to the side of the foam away from the foil. The results were superb.
Also I believe that you can get double glazed panels that have a vacuum between the glass.
I am afraid i cannot give you any brand names, search acoustic foam maybe?

regards
Martin

 

[Adam]

Also I believe that you can get double glazed panels that have a vacuum between the glass.

I thought this was the case with all double glazing.

Adam

 

[ProShop]

Philly's suggestion of using fire door blanks is a good one to consider,
the filling for these is (wait for it) plasterboard, yep, fire doors are filled with
plasterboard I've fitted hundreds of the things in the past, heavy work though.

I mention the plasterboard because it is also an excellent soundproofing material especially if the plaster used is barum plaster. it's more soundproof than chipboard or MDF.

 

[mahking51]

Adam
Pretty sure that is not the case..??
martin

 

[Keith Smith]

Double glazing units normally have air in the cavity, the aluminum strip which divides them has a desiccant to dry the said air to avoid condensation (till they leak), although it is possible to get argon gas filled units which have a higher insulation factor.

Keith

 

[ProShop]

Double glazing units normally have air in the cavity, the aluminum strip which divides them has a desiccant to dry the said air to avoid condensation (till they leak), although it is possible to get argon gas filled units which have a higher insulation factor.

Keith

I'll second that

 

[Anonymous]

Wow - a wealth of information - thanks a million!

The firedoor blanks is a good idea but I need to put a window in.

Ike - thanks for mentioning the bracing issue - I think I would've gone for too much of an internal framework.

Philly, I am beginning to think about having 2 pairs of doors, although space is quite tight and I'm not sure, unless the inner one is a sliding door, he'll have the room.

Lead sandwich! Wonder what that would do to your saw blades! I can imagine that's very effective though.

I've just been speaking to a very helpful guy at http://www.soundservice.co.uk who reckons you should use double or triple glazed glass with different thickeness of glass in each for maximum soundproofing effect. The wider the gap the better too.

The more you go into it, the more complex it becomes!

Thanks everyone,

Phil

 

[ProShop]

The firedoor blanks is a good idea but I need to put a window in.

No problem with putting windows in the top 1/3rd of the door, they are designed for that as well.

 

[Johnboy]

Adam, do some sums on the load the glass would have to withstand if it was a vacuum in the cavity. A 3ft square piece of glass would be loaded to about 20000 lbs :shock: I think the two pieces would touch in the middle

John

 

[Adam]

Adam, do some sums on the load the glass would have to withstand if it was a vacuum in the cavity. A 3ft square piece of glass would be loaded to about 20000 lbs :shock: I think the two pieces would touch in the middle

John

I was presuming only a partial vacuum!

Adam