Mid-Floor (in-between floors) Batts

Hi,

We are building a double storey house on a suspended timber floor in Victoria. I've just been told by my builder that to meet 5-star energy compliance in Victoria I need to get mid-floor batts installed (We already have sub-floor batts included in our original quotation).

My understanding was that mid-floor batts are only good for sound insulation and that it has minimal thermal benefits. Is this true? Is installing mid-floor batts a bona fide method of achieving 5-star compliance?

Thought I would ask the question here before hassling my builder about it.

Any advice or experience would be helpful! Thanks..

The only time you may need upper storey floor batts is when the floor is exposed to the exterior (cantilevered out over the lower floor) or over a garage or the like.

Hey

Not sure what the regs are in Victoria but I agree that mid-floor batts will have minimal thermal benefit. Is there a standard you can refer to for information?

Pix

Thanks for the comments.. I spoke to an energy rating consultant who tells me that whilst uncommon, it can be prescribed to get across the line for 5 star compliance. I am told they bang all the factors into a software program which zones your home into discrete living areas and computes an overall 5 star score. For our design and orientation on the block the mid-floor batts, I am told, do have an effect on the overall score and the alternative was to re-size certain windows.

We have accepted the insertion of mid-floor batts as it wasn't overly costly anyways but I admit the jury is still out in my own mind as to their ultimate effectiveness.

I suppose, irregardless of thermal performance, it will still at least provide some sound proofing between floors.

I'm in NSW and didn't need to install any mid-floor batts but I did it in the hope of making everything more sound proofed. It was a waste of $2k as far as sound goes, it all goes straight up the stair well, we laid solid timber flooring on the builders particle board, no carpet in sight.

Without any scientific measurements, just by feel, I do believe it is at least providing thermal shielding.

We wanted to install Sub flooring insulation but ran out of time have it done before the gyprockers appeared to do the ceilings. We REALLY wanted it to reduce the noise from the kids upstairs and the garage. It seems that we didn't miss much as far as A. Ryder says. We are having carpet and top level underlay upstairs so hopefully that will help. I will probably even have a few rugs on top of that as well. We had insulation stuffed into every cavity in the house we could though. Fingers crossed all that plus the carpet will help. Too late now anyway

The carpet will make a big difference and most will probably be all you need.

If and only if you've blocked all other avenues for the sound to travel through then yes mid-floor batts will add icing to the cake but if the sound can just rush straight up the stairs or across solid timber flooring then there's not much point

A.Ryder, you probably ARE benefiting from it, because I guess it would be worse if you DID NOT have it. You would probably really notice the difference.

A.Ryder,

Yeah, to my mind, the thermal shielding between upstairs and downstairs was the only real thermal benefit I could think of, but even then I suppose the heat can simply charge up the stairwell void. Maybe the closed off rooms upstairs might benefit.

Jury is out regarding noise, we won't know until we live in it I suppose.

My parents have timber floors on top of particle board on the second storey and it is quite noisy. In the rooms which have carpet though the noise transference seems to be significantly less. Anyways, its just anecdotal, like yourselves, we do not have any measurements.

We have mid floor batts but we used R2.0 soundscreen, we have carpet on 10mm underlay and unless my boy is jumping off the bed then it is pretty silent.

I also encased the office and laundry in soundscreen batts combined with soundchek gyprock. Brilliantly quiet, can barely hear the washing machines and don't realise that I have kids when I am in the office.

As for thermal when you walk from upstairs downstairs it is like walking into a fridge. By biggest problem is trying to work out how to cool upstairs?

any tips?

Dan