Installing soundboard

I'm replacing a ceiling with some pine wood panels.
I also want to soundproof it a little bit as the ceiling is comletely open to the floorboards above.
The room above has painted floorboards, no other floor.
The joists are also not level so I need to put in some strapping.
Where in the layering should the soundboard go?
If I put joists-->soundboard-->strapping->panels then there are 2 air gaps.
If I put jpoists-->strapping-->soundboard-->panes then there is only 1 air gap.

 

What type sound board are you installing? What is its rating? How thick is it? How do you propose to install it? Screws?

 

I was just going to use dry wall unless soundboard would be better?
I would intall it with screws onto the strapping probably but it could also be above the strapping.

 

Strap the joists, install Roxul between the joists, then sheetrock. About as good as it will get without decoupling the ceiling from the joists.

 

Do you put the Roxul in first and then put the strapping on after?
Also, is there any need to use drywall under the joists if you;ve used Roxul? There would then be panelling underneath the drywall also.

 

Well,no. I made the reference to sheetrock in error. Forgot you were using wood panels. I would install the Roxul before strapping.

 

So, is Roxul better than just drywall, abosrbs sound and also keeps in heat?
I can see through the gaps in the floorboards of the floor above at the moment so is there any need to seal ofs those gaps or will the Roxul do the job?
I'd like to stop dust coming through from the floor above into the ceiling space but also be able to vacuum some of the dust that collects in between the floorboard gaps.

I've heard 2 layers of drywall with green glue in between might also be an option?

 

Roxul is insulation batts. Drywall is flat sheets 1/2" thick. Apples and pears. If there are spaces between the flooring above, then it must be covered with solid flooring above.

 

The flooring above is the final flooring though...it is painted floorboards.
I thought maybe adding thin strips of cardboard on the underside just in the gaps but not sure if that passes building code.

 

I'd shy away from cardboard. You could insert plywood or styrofoam in between the joists underneath the flooring.

 

to completely fill the 16inches between joists or just glue it to the underside to fill in the gaps in between floorboards?

 

Since you have gaps in the flooring above I'd cut sheets to go from joist to joists, either that or install new flooring above that wouldn't have the gaps.

 

How do you secure the foam in place especially if the joists move a little bit under load from walking across them?
Eventually, this might push a tight fitting styrofoam loose?

 

I'd cut and nail cleats under the foam to hold it in place.

 

Cleats? Like a small metal right angled support?

 

A 1x2 or whatever, just some wood to hold the foam in place.

 

The problem I have is that the 2 ends of the walls are panelled but they are not lined up correctly. So, if I run panels along the ceiling in a straight line, then it will look like everything is misaligned as the 7inch wide panel on the ceiling will not line up with the 7inch wide panel on the walls.

Also, there are wires that have been fished, if I move these to holes in the joists, I am worried that there will not be enough wire to reach the outlets or junction box. Can I just secure the wires alongside the strapping?

 

I don't know what the code is in regards to the wiring but you need more strapping if you wish to attach the ceiling to it. 16" centers is best but absolutely not more than 24" centers.

 

No, I haven't put any strapping on yet, that is some old strapping for the original suspended ceiling.

 

You are walking on the floor boards above??? They seem awfully thin for the span without a plywood subflooring on top of it.

 

Yep, it's a bedroom above so not much weight.
They are pine - I think 7 inches wide around 3/4 thick.
The joists even have some bark on them!

 

Is cardboard not allowable under building code? Just looking for a cheap option as Styrofoam seems more for insulation?

 

What is it you think the cardboard would do for you? I don't see a problem with it but I'm just not figuring out where it fits in the overall solution.

 

I'm simply trying to block the gaps in between floorboards so that dust does not style in the cavity when I then create a ceiling from below with drywall and planks. The cardboard between floorboards on the floor above would allow me to vacuum dust out. I did also want to soundproof between floors but the drywall should do a bit.

 

Without flooring or plywood on top of your subflooring, you won't be able to stop stuff from falling through. Not sure why you only have subflooring anyway.

 

I think when it was put in originally it was put in as cheaply as possible.
So, the subfloor (pine planks) is also the primary floor.
I don't see a problem with that in a kind of rustic look but the gaps are obviously bigger.
Even with a hardwood floor over it, some dust would get into the cavities?
There must be some way to stop that or insulate against it from underneath?

So far, I have
-cardboard, which some said I couldn't use but not sure why not (water damage maybe). Would have to be glued/nailed to the underside of subfloor.
-styrofoam cut to fit in between joists - more expensive and might move over time with the joists flexing. Secured with cleats, nails or something.
-drywall - heavier and probably more expensive but has some soundproofing properties. Screwed into subfloor or secured with cleats. Makes it more difficult to pull up sibfloor from above in future.
- Roxall - very expensive and dust would collect.

 

You're not going to stop the dust from getting through from below - this is the same process as people who wanted to stop water getting in their basement by painting the inside wall. You need to put something over the boards so the crud can't get between the boards in the first place.

 

The floor is painted and finished now so the only option seems to be from underneath without an expensive hardwood flooring put on top.

 

When hardwood is laid over the subfloor you lay down roofing felt [mainly to eliminate squeaks]. That and the fact the hardwood should have smaller cracks [if any] would prevent dust from settling thru to the floor below.

I would have applied a bead of caulk in between the cracks prior to painting which while not an ideal solution - it would stop the majority of dirt/dust falling thru.