I have a bouncy floor that needs to be insulated and stiffened up. Currently, it consists of only 50x150mm floor joists with 580mm c/c. The problem is the span that stretches over three meters, making the floor quite bouncy. Below the floor is the basement, and there's not much ceiling height to spare—maybe 50-60 mm, but that involves quite a bit of work. In the room above, the ceiling is already low, so I'm quite stingy with millimeters there.
To make it even more complicated, I have a ground source heat pump and an ejector pump in the basement, and the room above is intended to become a bedroom. Therefore, the floor should be reasonably sound-insulated. I'm not expecting studio-quality insulation, but you do your best
I was thinking of installing asphalt board as a subfloor, then placing windproof paper in the compartments and filling them with ground slab to obtain a heavy insulation that hopefully dampens the worst of the noise. Then, glue and screw down chipboard on the joists, and over that, hydronic underfloor heating and 40-50 mm fiber material. On top, it will likely be wall-to-wall carpet or possibly vinyl flooring.
The joists may need further stiffening, so I'm considering whether to reinforce each joist with plywood on each side, using plenty of screws.
Could this work?
Would a 3 mm metal sheet do a better job, or is 12mm plywood sufficient? 16?
Would plasterboard in the basement be better instead of asphalt board?
Is it worth the hassle to use ground slab instead of regular mineral wool?
To make it even more complicated, I have a ground source heat pump and an ejector pump in the basement, and the room above is intended to become a bedroom. Therefore, the floor should be reasonably sound-insulated. I'm not expecting studio-quality insulation, but you do your best
I was thinking of installing asphalt board as a subfloor, then placing windproof paper in the compartments and filling them with ground slab to obtain a heavy insulation that hopefully dampens the worst of the noise. Then, glue and screw down chipboard on the joists, and over that, hydronic underfloor heating and 40-50 mm fiber material. On top, it will likely be wall-to-wall carpet or possibly vinyl flooring.
The joists may need further stiffening, so I'm considering whether to reinforce each joist with plywood on each side, using plenty of screws.
Could this work?
Would a 3 mm metal sheet do a better job, or is 12mm plywood sufficient? 16?
Would plasterboard in the basement be better instead of asphalt board?
Is it worth the hassle to use ground slab instead of regular mineral wool?
There is a method called cross-nogging to increase the stability of the joists. There is a picture in this thread http://www.byggahus.se/forum/golv/28518-absolut-baesta-saett-att-laegga-stavparkett.html.
In bathrooms (or rather on ceramic boards), 300mm centers between floor joists are commonly used.
When soundproofing rooms, double mineral wool with an air gap in between is used. The boards on the wall must not have the "same" stud, otherwise sound travels through the stud.
Everything depends on how much time you have for your project and what end result you desire.
You are thinking of casting on stone, which will give a very heavy floor that is difficult to set in motion. Additionally, it requires stable joists that can handle the weight and deflection.
If you believe that the joists can handle the load without reinforcement, proceed without any reinforcement. The entire upper layer will be incredibly stable.
If you still have problems with sound, you can place rock wool (not glass wool) in your basement ceiling. Hold the rock wool in place with a combination of staples and wire.
If you are still having problems, nail new studs into the basement ceiling perpendicular to the floor joists. Place rock wool between the studs, and then I would suggest installing a gypsum ceiling board or similar.
In bathrooms (or rather on ceramic boards), 300mm centers between floor joists are commonly used.
When soundproofing rooms, double mineral wool with an air gap in between is used. The boards on the wall must not have the "same" stud, otherwise sound travels through the stud.
Everything depends on how much time you have for your project and what end result you desire.
You are thinking of casting on stone, which will give a very heavy floor that is difficult to set in motion. Additionally, it requires stable joists that can handle the weight and deflection.
If you believe that the joists can handle the load without reinforcement, proceed without any reinforcement. The entire upper layer will be incredibly stable.
If you still have problems with sound, you can place rock wool (not glass wool) in your basement ceiling. Hold the rock wool in place with a combination of staples and wire.
If you are still having problems, nail new studs into the basement ceiling perpendicular to the floor joists. Place rock wool between the studs, and then I would suggest installing a gypsum ceiling board or similar.
Hello,
I have just reinforced our 45x145 joist that spans about 3.5m. I glued and screwed 12mm P30 plywood on each side of the beam and applied cross-bracing. I haven't laid the floor particleboard yet, but I already feel a big difference. I think one of those actions would have sufficed, but since the floor is already up, I thought it might as well be good to do both. We'll see in a couple of weeks what the final result will be
Best regards,
Y
I have just reinforced our 45x145 joist that spans about 3.5m. I glued and screwed 12mm P30 plywood on each side of the beam and applied cross-bracing. I haven't laid the floor particleboard yet, but I already feel a big difference. I think one of those actions would have sufficed, but since the floor is already up, I thought it might as well be good to do both. We'll see in a couple of weeks what the final result will be
Best regards,
Y
I hadn't even thought about cross-battening, it's probably a good idea. Combined with some plywood like yllom did, it might just work. There's no space for air gaps and other luxuries; unfortunately, I only have 150 mm to work with, so it'll have to be as it is.
yllom, what did you screw and glue with? My beams were probably straight fifty years ago, but today the wood has dried and warped into a bowl shape, so it will likely require some force
yllom, what did you screw and glue with? My beams were probably straight fifty years ago, but today the wood has dried and warped into a bowl shape, so it will likely require some force
If there aren't too many studs, I suggest you replace them..
If they are crooked, they easily crack when you try to screw on ply..
Then switch to kertobalk instead.. or if you have time, saw strips of plywood
and make your own kerto beams.. possibly if you place them between the ones you already have..
But as magnu writes.. it will be difficult with soundproofing. But markskiva should probably be the best at damping..
If they are crooked, they easily crack when you try to screw on ply..
Then switch to kertobalk instead.. or if you have time, saw strips of plywood
and make your own kerto beams.. possibly if you place them between the ones you already have..
But as magnu writes.. it will be difficult with soundproofing. But markskiva should probably be the best at damping..
I used waterproof wood glue and screwed the plywood so that it lay as tightly as possible against the stud. My studs were also not completely straight, but replacing them was not an option since the under ceiling is nailed to it. Therefore, it was plywood + cross-bracing.
Best regards, Y
Best regards, Y
The key with soundproofing is to avoid areas where sound can easily get through. Holes and gaps are completely unacceptable.Strip said:
A large part of the sound is dampened by forcing the sound to change its transport medium. My understanding is that 70+50mm stone wool with a 20mm air gap in between dampens sound better than 150mm stone wool.
My idea was that you should press in 100mm stone wool between the studs at the top.
If that wasn't enough, you could lower the ceiling those few mm with new ceiling joists placed across the existing floor joists.
On top of the ceiling panels, you can then place a thin layer of stone wool, which dampens the vibrations. Then you have an air gap of 20-30mm.