Author Topic: Advice for better soundproofing - first steps not enough!  (Read 7698 times)

ritzta

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Advice for better soundproofing - first steps not enough!
« on: November 24, 2011, 10:00:10 AM »
I have a detached home that about 25 ft from a road in the city (traffic around 35 mph).  The layout is big and open, with high ceilings.  The house sits between 2 similar homes, with a few feet on either side. Soundproof interior windows installed over all but 1 rear window (far from the noise).  I then had an acoustically rated storm door placed over my solid wood front door, which faces the street, some improvement (ISTC of 42). If there is anything running in the house (fridge, a TV) there road sound is virtually unnoticeable.  However when the house is quiet, the road noise is prominent.  I noticed that sound comes through unsealed areas around the front door frame, and my fireplace vent emits noise.  I have glass block on a few side walls which seem to be a sound leak as well. All brick construction. The front walls are 16+ in deep, 12 in on sides. Where do I go next?  Treat walls? I am feeling a bit desparate for a more total solution.

Randy S

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Re: Advice for better soundproofing - first steps not enough!
« Reply #1 on: November 25, 2011, 02:00:16 AM »
Are you on a raised foundation or slab?
do you have finished wood floors / tile or carpet and padding?
do the eves / over hangs of the house face the noise source?


glass block will have to be treated like a window....second panel needed with airspace.

You MUST seal all air leaks around all doors and windows..... soundproof systems rely on the dead air space to reduce noise, if one side of the system has a leak you will not get maximum reduction your assembly can achieve.





Randy Sieg

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Randy S

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Re: Advice for better soundproofing - first steps not enough!
« Reply #2 on: November 25, 2011, 02:00:58 AM »
also keep in mind that because you have a double pane window that you will not truly achieve the manufacturers rating...there are a couple factors in play here...1)the depth of air space dictates the STC value with mass of panel not the window rating. Example: 1/4" glass / 1" airspace / 1/4" glass = STC 37    same glass with a 2" airspace = STC 43.
also for window ratings STC and OITC are about an average of -8 STC difference. So you can view OITC as a more accurate value.
2) you still share the same window box.....inside and outside.  In a recording studio we build a double frame with double window box to avoid a structural connection.. This is not a cost effective assembly for a standard home so the maximum window reduction would be equal to the wall value at best and if you still look at the windows when you hear street noise then that is still the weakest point.
Randy Sieg

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888-942-7723
Ph. 760-752-3030
Fax.760-752-3040

ritzta

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Re: Advice for better soundproofing - first steps not enough!
« Reply #3 on: November 25, 2011, 04:13:51 AM »
Thanks for your comments.

I am on a foundation that is raised.  The first floor of the home is about 5 feet from the ground / road level.  It is a concrete foundation.

The first and second floors of the home have hardwood throughout.

The eaves do not face the road, however I have a front porch with a roof (5 foot deep) that does face the road. 

I was lucky - I have a lot of space between my primary and interior storm windows; about 6 inches.  I do not think those windows are the problem.  When I hear the sound, I look at the front door, which is under that porch roof! 

Good point on the glass block. I was thinking about getting laminated glass interiors over them, and having them frosted to make light boxes.  Glass block is homely anyway.

ritzta

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Re: Advice for better soundproofing - first steps not enough!
« Reply #4 on: November 25, 2011, 04:25:05 AM »
Do you think my porch is trapping sound and pushing it to the door?  Is there a way to soundproof the fireplace vent (which comes right out of the side wall away from the road into a square vent)? 

I had this thought of turning the open porch into an enclosed one and that would block the sound coming in through the door area.  Maybe that's a worthy few thousand dollar investment and a nice home addition as well.

When I open the soundproof window and listen, I hear cars.  When I close them, they are nearly silent.

I attached a photo of the front of the house that faces the road, for reference (before I added the storm on the front door!)

Thank you so much for your helpful comments!

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Re: Advice for better soundproofing - first steps not enough!
« Reply #5 on: November 25, 2011, 02:54:12 PM »
Ok keep in mind that there is no such thing as 100% soundproof...it comes down to diminishing point of return.
you could have a few potential culprits here...First and fore most, you must seal the front door correctly before investing on the patio. The patio is trapping street noise and allowing it to stay longer = more noise   
If the door is sealed properly, the noise(vibration that is trapped by the porch) can be transmitted through the structure.
It is critical that all your current leaks are sealed in order to attempt gaining any more value...

The fireplace can act the same way as the porch, which requires the same approach. Dead air space.

The raised foundation is acting the same way as the porch as well, I suspect that the underside is open joist and empty(no insulation).

The hardwood floor (especially nail down) are major conductors of street noise vibration which can take vibration and expedite it through out the home.
Randy Sieg

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888-942-7723
Ph. 760-752-3030
Fax.760-752-3040

Randy S

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Re: Advice for better soundproofing - first steps not enough!
« Reply #6 on: November 25, 2011, 02:57:33 PM »
You can get an idea of what Im talking about by taking a regular drinking glass and using it to expedite the LF that is going through the structure....the glass creates the triple leaf effect...put the glass to the floor and your ear to the bottom...see if it is the frequency range you are hearing...most likely a low drone.
Randy Sieg

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www.soundproofing.org
888-942-7723
Ph. 760-752-3030
Fax.760-752-3040

Randy S

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Re: Advice for better soundproofing - first steps not enough!
« Reply #7 on: November 25, 2011, 02:59:30 PM »
one more thing.....if the home is mostly hard surfaces than sound that does get in will stay longer and therefore sound louder.
You must have some value of absorption or you become the sound sponge.
Randy Sieg

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888-942-7723
Ph. 760-752-3030
Fax.760-752-3040

ritzta

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Re: Advice for better soundproofing - first steps not enough!
« Reply #8 on: November 25, 2011, 03:10:11 PM »
Thank you - all quite interesting.

The basement ceiling aka floor joists are insulated and drywalled.  The basement is pretty silent in general.  How does one create dead air space for the fireplace? 

I do have a significant amount of carpet, but maybe some more interior fabrics (aka drapes, etc) would help cut down on the echo.

I think I'll start by sealing up all the door leaks, maybe replace the weather stripping, add a second window to the glass block and figure out something for the fireplace.  Would a few foot stone wall offer any protection for the raised foundation of the basement?  I know it won't cut down on noise that rolls over it, but would it deflect some?

I would love to just pay an acoustic engineer for their opinion, but finding one has been a challenge (Chicago).

Thanks again!  Very informative and great forum.

Randy S

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Re: Advice for better soundproofing - first steps not enough!
« Reply #9 on: November 25, 2011, 03:24:59 PM »
Great to hear about the basement ceiling!..that is quite a common problem...

Absolutely, get all your current leaks sealed ..this will make a noticeable difference.

You are in the right mind set,,, the wall is only as good as the height/ distance to source and mass of the wall. So it might not show a noticeable value due to height. Not cost effective.

You might be disappointed hiring the engineer, (no offence to fellow engineers) however you must understand that once you have achieved a 50% reduction of noise the chances of you achieving 50% more are slim to none...at that point you only achieve small increases (10%-20%) at best..and you must be careful due to cost vs. reduction gained...I normally take alternative measures like cancellation or absorption.   
Randy Sieg

Super Soundproofing Co
www.soundproofing.org
888-942-7723
Ph. 760-752-3030
Fax.760-752-3040

Randy S

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Re: Advice for better soundproofing - first steps not enough!
« Reply #10 on: November 25, 2011, 03:26:44 PM »
seal up the door AIR tight!.... after that let me know what the results are...you can reach me direct during the week.

Randy S.
1-760-752-3030 ext 104
Randy Sieg

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888-942-7723
Ph. 760-752-3030
Fax.760-752-3040

Idlewild

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Re: Advice for better soundproofing - first steps not enough!
« Reply #11 on: December 01, 2011, 11:30:37 PM »
i have a related problem with road noise being about 75 feet from a road where loud trucks can vibrate the walls and even the bed!  There are no windows on the road side in the bedroom.  I have 2x4 walls with a fiberboard fake woodgrain type sheathing.  As a DIY project I would like to add another layer of siding to the outside.  would I lose the usefulness of green glue because of the uneven nature of the outside siding or could this be overcome with 3 tubes per sheet?  Would I gain by applying plywood or OSB first or by using 2 layers of green glue?   Or would one layer of MLV and one layer of green glue be better?  What do you think Randy?
Jack

Randy S

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Re: Advice for better soundproofing - first steps not enough!
« Reply #12 on: December 01, 2011, 11:38:42 PM »
Jack,
For the outside just use 3 tube green glue and 3/4" OSB or you could use stucco!
The real solution for you will be treating the room inside after you have added mass to the outside...if you can feel the vibration we have to decouple from the structure to get a decent reduction otherwise it will be like you putting your hand on a speaker while its playing....its still playing just not the same way...muffled.
you need to unplug the drywall from the structure.
Randy Sieg

Super Soundproofing Co
www.soundproofing.org
888-942-7723
Ph. 760-752-3030
Fax.760-752-3040

 

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