sound proofing question

[jon s]

quick question...

in my basement i have walls: brick/cavity/brick and have found a table giving an STC of 50 for this construction

i don't have space for 'room within a room' construction and it's not that essential anyway. the room has a false ceiling suspended form the inner cavity which appears to be isolated, so i have an STC of around 54 in that direction

i'm considering putting double plasterboard to the inner face of the cavity walls, but i can't find a table giving an STC for this, can anyone help?

thanks,

jon

thanks,

jon

[knightfly]

I don't have established STC values for that either, but if you truly have the ceiling performance you mentioned and NO FLANKING PATHS, then two layers of wallboard over the brick should bring the wall up to (or maybe 1-2 dB over) the performance of the ceiling.

With those stiff brick walls, I'd start reading about bass traps, if you haven't already... Steve

[jon s]

thanks for the relpy

I'd start reading about bass traps, if you haven't already

oh yeah! i've been working on this in the studio design forum, the whole room is covered with one form of trap/absorber or another (except the floor!)

John suggested this "I think the easiest way is to bag it. That's a loose sand cement mix you wash onto the surface with a cloth. It seals the surface" as a quick and simple way of improving things, i've never heard of this, what's the method? is it better that plastering the wall?

thanks,

jon

[knightfly]

We're "passing each other in the night" here - I've not heard the term "bagging" before this, but generally you're just making a relatively thin mortar mix and wiping it onto the brick so that it soaks into the pores and seals the brick. And no, it's not better than plastering. If you put a thicker layer of plaster on, you not only seal the brick but add more mass which will improve STC also - about 2-3 dB per 1/2".

If you've not already, check your thread in the design forum for a couple more pointers... Steve