I live next to a train track. I have an amazing view but on occasion, the trains sit in front of my house and just idle, drives me crazy. I plan on building in about a year and am researching the most soundproof homes, this is the most important aspect so if there is any difference in these , please educate me. I am curious about pricing as well. I see a lot of info saying that ICFs are 2-6% more than wood construction but I see wood houses in my area range quite a bit. The plan is a simple rectangle with 1200 sq. foot basement/garage and 1200 sq. foot living area on top of it. I know any figures thrown are just shots in the dark but will probably more accurate than what I've been able to come up with. I would just have it built to shell and wire, plumb, and do the interior myself. I am leaning towards the sandwich concrete walls like thermomass and easi-wall as I like the look of bare concrete and would save me some money for siding. Any thoughts or help is appreciated.

If you want thicker insulation, consider standard poured concrete walls with EPS and then stucco on the exterior. Also consider formliners to make the concrete look interesting.

Posted By Floundering on 29 Nov 2014 03:16 PM
I live next to a train track. I have an amazing view but on occasion, the trains sit in front of my house and just idle, drives me crazy. I plan on building in about a year and am researching the most soundproof homes, this is the most important aspect so if there is any difference in these , please educate me. 

I built my house with Buildblock 11" forms, 2.5" foam both sides and 6" concrete. I live less than 1/2 mile from a busy rail line. My experience is that 90% of the train sounds we hear, which is both the horns and rolling rumble, come in through the window glass. The sound level is not very high, and I probably don't hear most of the trains since I'm sure I just tune them out. The sounds are most noticeable at night when things are quiet and the cooler air carries the sound better. My windows are Andersen 400 series.

So I'm going to suggest that your choice of wall construction is by far a secondary consideration to the size, placement, and type of windows you use. If you can avoid it, don't put any windows on the side toward the railroad, or at least minimize the size and number as much as possible.

It's the mass of the solid concrete that makes the difference in noise. I knew an architect who designed and built a home 15 (fifteen!) feet away from a freeway overpass. It was made with simple CMU block, and the cores were filled solid with grout, and it was a concrete flat roof with a built-up commercial type finish. On the outside the freeway overpass was deafening, but when you got inside it was peaceful and quiet. And like dmaceld says, there were no window or door openings on the freeway side of the house.

Unfortunately my view and the railroad track is right in front of me. I live in a cabin built in 1941 with single pane windows so whatever I build will definitely be better. I researched the window issue a little and appears that a secondary window with an air gap 4" or more could bring the stc rating up to that of a 6" concrete wall (depending on the window quality). I like the idea the other poster mentioned of pouring regular concrete walls and lining the inside with close cell insulation. I could do 2" and then a regular 2x4 wall with open batt. This would allow me to do almost everything but the structure bringing my cost way down.

This is about a 1/3 of my view. You can see how close I am to the tracks.

Are the tracks used constantly or just a couple of times a day? We have tracks about 1/4 mile away that they only use about 2x a day. It's been no problem at all. The only time I even hear them is around 11pm when everything is quiet. You do have an 'amazing' view!!

From a thermal performance standpoint, it is much better to have the wall mass on the inside of the insulation rather than the other way around. ICF is a good practical compromise. Having all of the insulation on the inside of the thermal mass negates many of the thermal benefits of the concrete mass.

Depending on location, ICF walls generally cost around $12-$15 per sq ft of wall area installed. I installed mine doing it mostly by myself for around $6/sq ft of wall area (I paid an experienced crew to do the actual pour and run the pumper hose).

The tracks are used very often but I got used to the trains going by after living here a few months, no biggie. The real problem is they put in a staircase a mile away to do shift changes a few months ago so very often, the other end of the train is right in front of my house. I've had a train idling in front of my house as longs as 3 days and they have to relieve their air brakes every so often; it's so annoying.

I'm not opposed to ICF but I can't seem to find anyone in the area that's doing it around here (Tacoma/Seattle area). When you say $15 a sq ft, I'm to understand the shell of a 2400 sq ft home would be $36,000?

Has anyone priced out sandwiched concrete like easi-wall or thermomass?

What about roofs? ICF roof for noise as well or are there less expensive options the are just as quiet?

The cost is for wall area, not floor area, but for a square house with the configuration you specified it is about the same. It will be more expensive for anything but square.

Posted By Floundering on 30 Nov 2014 07:48 AM
.. When you say $15 a sq ft, I'm to understand the shell of a 2400 sq ft home would be $36,000?

It is based on sq ft of wall area, not floor area.  In your 1200 sq ft two level case assuming dimensions are approximately 30'x40' and 8' ceilings in the basement with 12" allowed for the upper level floor system and then 8' ceilings on the main floor, then the wall square footage almost exactly equals the floor square footage.  But if you change the wall height to say 9' ceilings on the main floor then your wall area jumps up to 2520 sq ft.  Just add up the length of all walls to determine your total wall length then multiply by the height of the walls.

Posted By Floundering on 30 Nov 2014 07:48 AM

What about roofs? ICF roof for noise as well or are there less expensive options the are just as quiet?

ICF roofs can get quite expensive.  A conventional truss roof with about R60 of blown cellulose on the ceiling should provide considerable sound attenuation due to the mass of the cellulose insulation.

You know, another lower cost option for your walls could be a double 2x4 stud wall with dense packed cellulose in the cavity.  If you make the framed double wall 8" thick with independent 2x4 bottom and top plates this would result in a 1" gap between the wall studs and would help to upcouple sound transmission from the outside wall to the inside wall.  And the dense packed cellulose at ~3.5 pounds per cubic foot would significant attenuate any noise transmission.  And you would have a wall with an R value of ~R25 whole wall.  On the wall facing the tracks you could double the thickness of the interior drywall to further attenuate the noise.  With a dense exterior siding such as cement fiber board siding, you could have a wall with a comparable to or better STC rating than an 8" concrete wall.  Another advantage is that conventional wall framing techniques are used here and any competent framing crew in your area can do this.

Since you care about low frequency noise, don't put any stock in STC ratings.

Thanks for correcting my math. I fully understand the pricing now. I've been researching a little on the double wall arkie6 had mentioned. It seems it's so successful due to the decoupling and the air space in between. Similar with the windows, two windows with a larger than 4" air gap in between is much much more soundproof than a triple pane one. A couple of articles mentioned that insulation is pretty much the same as air space as far as sound goes. I wonder if the thermomass wall would act like two independent concrete walls with air space in between or if the ties negates the decoupling effect? The concrete wall on the outside, then insulation, then 2x4 wall with sheetrock may not be good thermally but now understanding soundproofing better, might be the most effective.

To minimize sound transmission on an icf wall it is important to vary the thickness of material on each side of the wall. Adding resilient track to the inside before drywalling decreases sound transmission further from an already fairly effective icf wall. Definitely as mentioned above the windows will still be a big issue. No windows on the train side would be optimal ...not sure about practical.
Good luck

This could be a case where window shutters make sense. Ie, a view during the day and quieter at night.