Wall STC could be a limiting factor ?

[rixensart]

Dear all,

I have just bought an old house (1960) with a "regular" wooden frame. Walls are not in brick: just plywood and shingels. The house is facing a very noisy street and I would like to change the thin old single pane windows. I have read a number of posts and I have seen that STC is a Key Performance Indicator for window accoustic insulation however accoustic insulation is a "global" problem meaning wall accoustic insulation should also be taken into account when buying windows with "high STC".

For instance vendor X sells windows with STC= 37. Is it worth for me to shop for windows with an higher STC ? Or are my wooden frame walls going to be the bottleneck STC wise ?

Thanks for your help.

[Windows on Washington]

A 37 window is pretty darn good.

Perhaps going to a 40-42 might not be overkill in this case depending on wall construction.

http://www.stcratings.com/assemblies.html

Check the attic insulation levels as well.

[rixensart]

Many thanks for the URL.
It provides me with the STC estimates/numbers I was looking for the walls.

However your feedback about attic is quite interesting and I have another question. However I realize that my question is not strictly related to windows replacement. So apologize for sidetracking this thread.

My bedroom is just below an attic with "normal insulation". Normal means nothing special. The roof is made of 20 year old shingles (facing the busy street). It has two small windows (not facing the busy streets, orthogonal to it) that will be left a bit open when it gets very hot.

I have planned to change the roof. Would it be a better idea to add up another shingle layer (to increase the accoustic insulation of the roof) versus removing the old shingles and adding new shingles ?

Again thanks for your help.

[Windows on Washington]

No.

Add more insulation...unless you are sleeping in the attic.

Insulation should be across the attic floor and about 14" tall in total. That will keep the noise at bay from that surface of the home.

[Soundview]

Rixenstart
I can tell you that just adding new double pane windows will make a big difference. I cannot tell you how many customers of mine were pleasantly surprised by how much outside noise was reduced when simply replacing their old windows; especially since you only have single pane. Believe it or not, adding foam to a windows extrusion( foam filled frame) helps reduce noise as well as having a non metal spacer system.
You can also try triple pane but going to a laminated glass with a 35 stc will render a remarkable difference unless you live under train tracks.lol
Also, be prepared for almost a $200 upcharge for laminated glass.

[HomeSealed]

If you currently have leaky single pane units you should see a marked improvement by simply upgrading to an airtight double pane window. Laminated glass is great, but generally overkill unless you have a pretty extreme circumstance.

[Windows on Washington]

I would be prepared for more than $200 for laminated glass to be honest.

+1

Air-tightness counts. Sound moves on air. A window with a higher air infiltration rate will leak more noise as well when compared to a similar window with a lower air infiltration number.

[TheWindowNerd]

That explains why the first thing my customers notice with a .01 AI window is that they can no longer hear their kids outside.

[Brewster]

I have just bought an old house (1960) with a "regular" wooden frame. Walls are not in brick: just plywood and shingels. The house is facing a very noisy street and I would like to change the thin old single pane windows. I have read a number of posts and I have seen that STC is a Key Performance Indicator for window accoustic insulation however accoustic insulation is a "global" problem meaning wall accoustic insulation should also be taken into account when buying windows with "high .

Rixensart
I had laminated glass windows installed in march and it made a very noticeable difference.
The laminated glass was a 35 stc and the standard windows were a 28 or 29 stc that we had replaced in the back only. I can tell you that the back windows are much quieter than i thought and its a standard stc rating not laminated. I am close to a main road with loud trucks and buses and the difference is amazing. Most window companies dont really test for stc from what i remember, its just common logic that laminated will wipe out most of the sound unless you live next to a major airport.
As the other guys talked about already, laminated is very expensive( i used 1/4 inch which is most common Im told). So only use laminated where you really need it. If i had to do it over again, i would of done fewer windows with laminated as the 28 or 29 stc was fine especially going from single pane , non insulated glass.