Posted: Tue Feb 15, 2005 7:06 am
Kevin, from what little I fully understand about elastomers, one thing you don't want to do is run them continuous in this case - part of what makes them work for isolation, is being able to "squish", or deform. The larger the square surface area being compressed, the less compressible they are, and the less the "give" -
If you use a "puck" made from 3/8 thick material with a Durometer hardness of 60 and the puck has 1-1/2" of surface contact (as in, 1" wide strip with a piece of 2x lumber resting on it) then, if you've calculated total weight so each of those pieces is compressed by 15%, it will deform to 85% of 3/8", or about 0.319" - adding thickness to the same "footprint" and the same weight would add to the amount of deflection (I think) if the same amount of loading would cause the same PER CENT of deflection; I really need to find more time to study this phenom in depth, so please don't quote me on this.
Elastomers, in order to "work" as they do, can NOT be constrained in the directions they are not being compressed; so for a floor, you can not "box in" the elastomer sideways; it has to be allowed to "squish" or it will act much harder. This is why the continuous sheet isn't a good idea - it will act the same as if you put a box around the rubber, except at the very edges.
If you think you want more depth, simply contact cement two layers together - this part I'm sure of.
For the main part of your floor, I would cut your 3" wide 3/8" thick stuff into 1-1/2" strips and contact cement two layers for each puck, making them 3/4" thick - this will keep them wide enough to not want to "fall over", from any side loading during construction - then, for under the wall area of the floor, just put them closer together.
Don't forget to calculate total weight of the walls, spread over their length; and if you're also building a second ceiling that will bear on those walls, that total weight will also need to be averaged into the weight per puck along the perimeter.
BTW, "contrite" means apologetic or sorry, "trite" means over-used and boring - and neither should apply here. The goal of this site is edification,and the absence of expensive and time-consuming mistakes that can be accomplished by learning BEFOREHAND how to, and NOT to, do things.
To this end, you should NEVER stop asking questions until YOU are satisfied with your understanding. Only YOU know when that is, so ask until you fully understand. If that takes more time than usual, it's more than likely MY FAULT for being a crappy teacher, so don't give up until you get what you need... Steve
If you use a "puck" made from 3/8 thick material with a Durometer hardness of 60 and the puck has 1-1/2" of surface contact (as in, 1" wide strip with a piece of 2x lumber resting on it) then, if you've calculated total weight so each of those pieces is compressed by 15%, it will deform to 85% of 3/8", or about 0.319" - adding thickness to the same "footprint" and the same weight would add to the amount of deflection (I think) if the same amount of loading would cause the same PER CENT of deflection; I really need to find more time to study this phenom in depth, so please don't quote me on this.
Elastomers, in order to "work" as they do, can NOT be constrained in the directions they are not being compressed; so for a floor, you can not "box in" the elastomer sideways; it has to be allowed to "squish" or it will act much harder. This is why the continuous sheet isn't a good idea - it will act the same as if you put a box around the rubber, except at the very edges.
If you think you want more depth, simply contact cement two layers together - this part I'm sure of.
For the main part of your floor, I would cut your 3" wide 3/8" thick stuff into 1-1/2" strips and contact cement two layers for each puck, making them 3/4" thick - this will keep them wide enough to not want to "fall over", from any side loading during construction - then, for under the wall area of the floor, just put them closer together.
Don't forget to calculate total weight of the walls, spread over their length; and if you're also building a second ceiling that will bear on those walls, that total weight will also need to be averaged into the weight per puck along the perimeter.
BTW, "contrite" means apologetic or sorry, "trite" means over-used and boring - and neither should apply here. The goal of this site is edification,and the absence of expensive and time-consuming mistakes that can be accomplished by learning BEFOREHAND how to, and NOT to, do things.
To this end, you should NEVER stop asking questions until YOU are satisfied with your understanding. Only YOU know when that is, so ask until you fully understand. If that takes more time than usual, it's more than likely MY FAULT for being a crappy teacher, so don't give up until you get what you need... Steve
- nuthin' new...
