Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
Well hollow core doors are not literally hollow. They are stuff with something inside thats not dense enough to block sound.
It depends. Some have (rigid) foam inside, in which case they are as soundproof as they're going to get, and the other suggestions about air-sealing the gaps are all that can be done.
Many have irregular zig-zags of cardboard producing some stiffness for the surfaces, and a half-dozen injection points should get dense foam into much of the door space, reducing its transmissiveness and tendency to boom/drum.
I built a set of double/french doors to acoustically isolate half a house. I had the advantage that there were no contiguous walls (the noisemaker was in a room that adjoined the rest of the house on an inside corner, and a garage wall). I built a double-thickness divider wall, put in two layers of isolated foam, and had a double-door unit built that, when shimmed and trimmed, had gaps you couldn't get a credit card into.
They were also 40+ pound solid doors.
It all kept the grand piano from deafening everyone in the protected half of the house quite well.
Buy and install some solid wood doors, not the pressed-fiberboard-with-a-bit-of-corrugated-fiberboard-inside crap you've got now. When you need extra quiet, put a couple towels or an old blanket down at the bottom of the doors.
Even completely air-sealing a door doesn't make a hollow-core any less sound-transmissive and 'boomy'.
You might try drilling holes into the core and filling it with the densest can foam you can find. Drill holes just big enough for the nozzle in the bottom, top, and through where the hinges attach. Holes along the edges would let you get more foam in between the cardboard spacers, but would have to be refinished, as might the top holes if they can be seen from an overhead location.
No, the interior of those types of doors is a heavy duty cardboard, which shouldn’t get wet. Spray foam insulation would absolutely make that wet, and then because it expands it could probably easily delaminate those doors and you’d have an exploded mess. My husband used to break those doors very easily into multiple little pieces using his foot and a hammer in like two minutes.
No, the interior of those types of doors is a heavy duty cardboard, which shouldn’t get wet. Spray foam insulation would absolutely make that wet, and then because it expands it could probably easily delaminate those doors and you’d have an exploded mess. My husband used to break those doors very easily into multiple little pieces using his foot and a hammer in like two minutes.
Spray foam doesn't contain water; I don't believe the trace of solvent would affect the interior door structure in any negative way; I've done it without problems.
Very difficult to "soundproof". You can achieve some improvement in STC by using good seals all around the perimeter, but the doors need to be replaced with solid core to make a noticeable difference. Hollow core doors typically have a honeycomb cardboard internal structure that will never be improved by spray foam.
Adding a heavy fabric to one or both sides will help some. It's all about decoupling surfaces to reduce vibration transmission.
If the seals around the perimeter don't do the job, install a drapery rod and soundproofing drapes.
They cost about $100 per panel, are about 4" wide and come in a variety of colors.
Just an update, sealing the air gaps properly helped tremendously. I don't even think I need to install solid doors at this point.
Thank you!
Please register to post and access all features of our very popular forum. It is free and quick. Over $68,000 in prizes has already been given out to active posters on our forum. Additional giveaways are planned.
Detailed information about all U.S. cities, counties, and zip codes on our site: City-data.com.
Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
Solly says — Be nice!
