Cheapest Way to insulate a timber floor in a qlder

Howdy guys,

We have pulled up all our carpets and polished the floors. The results are great there are only two or three downsides.

1. The floor is cold
2. The floor has changed the acoustics of the room
3. Need new skirtings.


Now number 1 and 2 are the ones I want to address.

I want to install acoustic insulation underneather the our little post war home.
Easy access underneath so that is not the problem.

The problem is I really need some way of securing the batts in between the floor joists. I had thought of ply then remembered how much it cost, then thought thin mdf or even fibre cement. I have at minimum 30m2 in the living room and 16m2 for our bedroom.

What does everyone reckon ?

Thanks
Tom

Why not fix building foil up to the underside of the floor joists and as you do each run push batts into the recess.

The best way to fix the foil is with Maxbond and use it like a contact cement by running a bead onto the bottom of the floor joist, push the foil onto the Maxbond bead and then pull it off let it tack off and then push it back on and it will stick like contact cement.

For a tempory fix while the Maxbond goes off you could use a staple gun with a small square of cardboard with the staple.

Tom,
the insulation under your floor will help with heat loss, but how much I'm not sure. I doubt it will do anything for the acoustics as the change has been brought about by changing the absorbent carpet for a reflective hard surface.

Mick

Mick,

I reckon you are right - from what I have read on the audio sites, the best I can hope for is to cut down on the echo the floor produces.

My main concerns are heat loss during the winter and cool air loss (or air con loss) during the summer

Barry I like your idea - just use the blue backed foil as if it were a giant roll of gladwrap and stick that in place with with batts sandwiched in the cavity

Tom

Quote:

---

Originally Posted by tcns

Barry I like your idea - just use the blue backed foil as if it were a giant roll of gladwrap and stick that in place with with batts sandwiched in the cavity

Tom

---

Yes just like that. If you wanted to make it quieter you could use Bradford Rockwool Mineral batts.

Look here. http://www.bradfordinsulation.com.au...eace+%26+Quiet

I,ve used acoustic insulation a couple of times and even built a professional recording studio. As stated earlier placing batts under the floor wont do a thing to improve you noise problem. You could change your ceiling coverage. There are hundreds of products and systems out there. Try to reduce parralel surfaces or surfaces at right angles to each other using furniture and artwork.
The way i've put batts between joists before is to drill holes (in a line) say and tread a wire along. Create these lines of wire about 1 metre apart then place your batts up inside them.They will sit up there and you can then line the bottom of the joist to form a ceiling if you want. the height of the hole in relationship to the bottom floor boards should be the thickness of the batt plus a generous amount to allow you to manouver the batt into position. If your using fiberglass batts you will want to do this as easily as possible. Go the white polyester rolls -easier and less itch. Also with the white poly rolls the material is stronger and lighter than say the green Acoustic batts so you can just staple them to your floor boards without using wire. Hope this is a help.

If you were to walk on a timber floor that is installed on ply over a concrete slab, the step noise level is low due to the solid substructure that prevents and absorbs sound travel.
If you were to walk on a standard tongue and grove on joist with out any acoustic insulation components fitted ,you will get a loud hollow sound due to reverberation and sound bounce. Similar to a loud speaker, signal is delivered to the cone and the vibration of the signal is amplified into the air. Same as a timber floor. Signal from the step is delivered to the timber board and the combination of fiber structure, framing structure and air cavity on the reverse side causes a amplification and is delivered into the air.
The solution is to reduce or eliminate the sound bounce and echoing.
This can be done , however not that easily and cheap. First you need to isolate all connections to the floor from the framing system. The board is attached to the joists, but the joists need to be isolated from the bearers and any vertical surfaces such as walls, skirting and and detail that comes in contact with the floor. You need to stop sound transferal through attached components to the floor. Wit the added benefit of acoustic matting attached to the underside of the floor is a bonus. This mat Will absorb any air Bourne sound coming of the board, It is a sponge. If you joists are exposed from the under side then you can perform the separation with lifting device and install products such as 10mm impactamat, shearflex or regupol . These are rubber pads that are designed to separate framing components to resist sound transferal. You will need to remove any skirting first . it would be best to get a professional in to do the job.

Go to www.timber.org.au and under the search field type in "acoustic"

How bout foil faced foamboard, will help both problems and you can just glue or staple it on.

Yep that will be an advantage in the absorption on the under side, but still need to isolate timber floor from rest of framing for it all to work effectively. Both need to be taken into consideration. Actually if a rockwool mat plus the foam board will be a help even if he does not isolate the floor from framing.

Quote:

---

Originally Posted by tcns

1. The floor is cold
2. The floor has changed the acoustics of the room

---

Larry I think that the point is the changed acoustics of the room not the acoustic properties of the floor.

Tom correct me if I'm wrong but I am guessing the acoustic problems of the room was very noticable when the room was bare but once you refurnished it they have diminished.

Quote:

---

Originally Posted by thebuildingsurv

How bout foil faced foamboard, will help both problems and you can just glue or staple it on.

---

What sort of foam are we talking about

http://www.spec-net.com.au/styrofoam/index.htm

Wont help the accoustics much, think it would do a bit though, a rug would probably be better.

You would have to be game to put polystyrene under your floor.

If you had a fire you'd be VSF.

I looked at the link and nowhere does it mention fire ratings. You would have to assume that if its for sale in Oz then it complies with the relevent standards. If it's been treated with retardants I would be equally cautious of using the product.

Most of these products have a fire retardent that prevents them from combusting. At the most they will just melt.