09-28-2020, 09:16 PM
(09-28-2020, 07:49 PM)ijmorlan Wrote:(09-28-2020, 07:03 PM)danbrotherston Wrote: There are generally fire code regulations for common walls and floors, that are usually pretty strong. That's also the reason for the roof edge you see on some (but for some reason, not all) townhouse condos, it's to prevent fire from spreading from one unit to another across the roof.
I suspect this fire rating should provide some sound isolation, but it would be good if there were specific codes for sound insulation as well, not the least because of class issues with townhomes.
That being said, yeah, I can imagine wooden towns without concrete construction, stacked townhomes could have substantial floor noise.
Just a single data point (well, 2 data points), but the townhouses I have lived in had common walls made of a single layer of concrete blocks with drywall glued directly on. Excellent sound transmission (which is bad, obviously), although probably OK for fire isolation.
I suspect that year of construction is strongly correlated with method of construction, but I don’t actually know anything about this.
I'm certainly no building expert, but you're right that probably provides some measure of sound insulation. To be honest, I'm a bit surprised that's a valid form of construction, drywall is a product that cannot touch moisture, while brick/concrete is a pourous material that can transmit water (even from the ground), so I wouldn't think gluing drywall to brick would be ... a good idea.
But you're certainly right, codes change over time (and also location), possibly that was permitted at one point and isn't now (or maybe it isn't even against code and I'm totally wrong here).
I've not lived in a townhome, but am in a concrete apartment building, the walls are drywall over studs over concrete walls, no insulation, and we get very little sound transmission.
Either way, it should evolve.