Questions Re: stud partitions, soundproofing, and slabbing

Out Of Order

Hey all,
I'm at the stage in my new build dormer bungalow where I need to put in the timber stud partitions and I have a couple of questions.

I was reading online about building a staggered partition but my carpenter made the point that the extra expense mightn't be worthwhile in my case, as I have a door in each partition that will kind of defeat the purpose. He questioned the availability of door frames for a 6" stud and advised that a normal 4" stud filled with fiberglass would be sufficient.

I have timber joists and he reckoned it was more important to soundproof between floors and that a good spec would be to:
Slab underneath as normal.
Put insulation between the joists (I'm doing this anyway)
Fit acoustic strip on the top of the joists and ply over that, followed by floor covering.

My next question is whether to skim the plasterboards (inc ceiling) or to tape and joint them. I'm not familiar with taping and jointing but I imagine that it would be much cheaper.

Thanks in advance, any opinions are appreciated!

RKQ

Out Of Order wrote: »

I was reading online about building a staggered partition but my carpenter made the point that the extra expense mightn't be worthwhile in my case, as I have a door in each partition that will kind of defeat the purpose. He questioned the availability of door frames for a 6" stud and advised that a normal 4" stud filled with fiberglass would be sufficient.

I'm not quite sure what you are asking!
Its worth considering two stagger studs to form a soundproofing wall between bedrooms. Personally I'd agree with your Carpenter but would use Rockwool flexi between studs, as its less likely to settled / sink if laid vertically.But I'd also double slab partitions to corridor & between bedrooms to get good soundproofing.

Out Of Order wrote: »

I have timber joists and he reckoned it was more important to soundproof between floors and that a good spec would be to:
Slab underneath as normal.
Put insulation between the joists (I'm doing this anyway)
Fit acoustic strip on the top of the joists and ply over that, followed by floor covering.

Good spec above but again double slab the ceiling, also put 19mm thick slab between joists on metal top hats if you can afford extra cost.

Out Of Order wrote: »

My next question is whether to skim the plasterboards (inc ceiling) or to tape and joint them. I'm not familiar with taping and jointing but I imagine that it would be much cheaper.

Personal choice / budget really. Tape & fill is cheaper as you only skim the joints in the slabs (yes a little to top of slab with ceiling). The plasterboard takes a good paint finish. Its popular in Commercial applications.
Some people prefer a full skim - a 3mm coat of plaster to the board, which can look well if done right.

sinnerboy

Here are some Stud options . Note the db reduction values

This is a usefull guide to db volumes .

Note the db reduction value of the simple stud partition in Table 2 page 63 - a 35db reduction .

From the Decibel (Loudness) Comparison Chart - you can see that 30db is the volume level you will find in a Whisper Quiet Library .

Numerically one can see why people often describe such partitions as being like "paper thin"

Will you get value from a staggered partition ? - look at Table 3 Page 64

mfceiling

Price difference between taping and jointing and skimming is not really that much to be honest.
Skimming is considered to be a wet trade whereas taping is relatively dry in comparison.
Taping requires 2-3 coats plus sanding - skimming is done once.

Your call really......

morning delight

sinnerboy wrote: »

Here are some Stud options . Note the db reduction values

How does a 100m block wall plastered on both sides compare?

sinnerboy

have a look

morning delight

sinnerboy wrote: »

have a look

Sound
Concrete Blocks are an excellent sound barrier because of their density. The sound insulation of a wall is related to the "Mass Law Curve". Outlined below is the approximate sound insulation that can be expected applying this law to Roadstone masonry products. The importance of good standards of solid mortar jointing cannot be overstressed if the desired standard of sound reduction is to be achieved. Failure to achieve the required reductions have largely been due to the presence of voids in the mortar joints, a serious reduction in wall thickness due to poor detailing or careless chasing of services.
Sound Insulations (dB Reduction)

Product
Concrete Masonry
No Finish
Standard Block
Heavyweight plaster
Standard Block
Lightweight plaster

90mm solid

42
46
45

100mm solid

44
47
46

140mm solid

49
50
50

100mm hollow

41
43
41.5

140mm hollow

43
46
45

190mm hollow

46
51
50.5

215mm hollow

48
50
49

C&P from link. I've highlighted one of the key points. The table values assume the mortar layer has no voids!

CJhaughey

Regarding flooring the joists upstairs, in my experience a lot of problems can be created by using non T+G flooring on the joists. Any flooring that doesn'y have t+g IS likely to start squeaking at some points where the sheets are butted together.
You would be better to use the chipboard double T+G and glue and screw it down to the joists. No movement and no noise.
4" stud double slabbed and filled with 4" rockwool that is non sag will make a big difference to noise levels while still maintaining a reasonably thin wall section.