Hi,
Does anyone know if you should insulate between the ground and first floor?
Is there any advantages or disadvantages? Someone told me its not done for new homes but i have no idea?
Cheers
Cobber
Printable View
Hi,
Does anyone know if you should insulate between the ground and first floor?
Is there any advantages or disadvantages? Someone told me its not done for new homes but i have no idea?
Cheers
Cobber
If you are planning a first-rate job, then yes. There should be some kind of moisture barrier over the soil, and ideally a membrane between the floor boards and the insulation. (with good sub-floor cross ventilation this may be overkill.)
Installing fiberglass bats under a floor is a huge pain-There might be some kind of spray applied foam that would be better.
There are many aspects to good insulation...the floor is probably down the list after attic/walls/glazing/spray foam in gaps.
Greg
On second thought, the moisture barrier under the sub floor isn't nescessary in a climate like this...it IS important though where freezing temperatures are typical because of condensation saturating the fiberglass and ruining it.
Greg
Thanks Greg. The sub floor is currently being built and the builder reckons they dont normally use insulation between the first and ground floor. I have left overs from when they ripped up the roof and am thinking about using them.
Builders don't normally do that because its hidden, and buyers don't know enough to ask for it. Most locally built houses are little better than tents when it comes to energy efficiency.
For your information insulating timber floors is now compulsory under the new invironmental requirements on all new homes and is in force for home additions over $100,000.00 and after June 2007 for additions over $50,000.00 and after June 2008 will be compulsory on all home additions.
Each home will have to earn 100 points under these new invironmental laws. More red tape.
Hi Barry...
What R value do the regs call for?
Greg
(who watched weatherboard being nailed to ripped and flopping tinfoil "insulation" just today.)
Barry - I was referring to the upstairs addition which will have chipboard as I will carpet it but you raise an interesting point. My extension is over 100k and they are not going to insulate the ground foor under the tongue and groove timber floorboards. What do you insulate it with? Im interested because the builder has said they dont usually do it. He said the timber will sweat if you put sisalation paper underneath for example?
cheers
Cobber
Not to sure on that but have heard R3.0 being bandied about.Quote:
Originally Posted by gregoryq
Cobber
In answer to your question just using foil wouldn't suffice as it wouldn't come up to the R factor.
The proper way to insulate any way is to have a vapour barrier between the inside cladding of the house and the insulation and to use a perforated foil on the outside of the insulation and the external wall cladding.
Cobber, I'm not Barry, but you can do a Google search on this stuff. "Fine Homebuilding" magazine, often covers this topic. Your builder claims the timber will sweat? Normally a well-sealed house has a higher relative humidity that the outside air. This water vapour will make its way through the membrane of the house to the outside air. In very cold climates, this water vapour is problematic with traditional fiberglass batting insulation, as it causes clumping, reduces the "R' value, and promotes mold growth.
The current method of coping with that is to line the joist cavities with heavy plastic, then install the batts. Chicken wire can be stapled to the bottom of the joists to hold the insulation in place, unless you can find paper-backed batts which can be stapled directly.
What spacing did the builder use on the joists? If its greater than 400mm you may have trouble with standard batts.
Greg
Barry/Greg - you guys have lost me there. There is no room to put thick insulation under the ground subfloor because I wont get the ducted heated in? I guess the issue is the timbe floorboards will have cracks in them later on and air will get through.
Barry - do you know where is says that its required by todays regulations? Do you have a link as it would be useful to show the builder.
cheers
Cobber
CobberQuote:
Originally Posted by Cobber
If the extension was approved by council before the 1/7/06 it doesn't have to meet the requirements for extensions.
Bazza - I reckon the extension was approved before then....doh.
Do you recommend putting foil underneath the joists maybe after the wiring? I saw in another post it was recommended. Cheers
Cobber, what's the distance from the bottom of the joists to the ground? I'm only talking about insulating the bays between the joists-you'd still be able to run the ducts between the bottom of the joists and the ground given 300 or so clearance.
I don't know how much you'd need for the installation...600 mm?
As a matter of personal opinion, I think foil is not worth the trouble-it has a very low R value, and even that is dependant on rip-free installation.
foil will help a bit especially with drafts. Foam board to the underside of the flooring can also help.
Greg - at the front of the house - the old part its around 700mm and then goes to 300mm...in some places in the new subfloor its 200mm.
I did ask the question to the builder about insulating in between floors and he said theres not point as the ceiling downstairs needs to be replastered and it will fall through...good point I dodnt think of.
cheers
Cobber
I would go the way of the foam board as it will be easier to install and if you had a fire in the house the last bit thats going to burn will be the floor on the bottom story unless you have kids playing under the house with matches.Quote:
Originally Posted by thebuildingsurv
Yes but there's nothing stopping him from putting the insulation in as it's being replastered. Sounds to me he just doesn't want to do it. It would be an extra that he could charge you for and make a bucket out of.Quote:
Originally Posted by Cobber
Cobber, It is the floor in between the ground and first floor you're asking about isn't it??
Thermal insulation - this would not really be needed unless you really kept one storey at a different temperature to the other.
Sound insulation - for general noise then increase the mass of the ceiling eg two layers of plasterboard and use rockwool batts, for impact sounds from footsteps then use isolated mounts for rondo furring channels - they really help.
Cheers
Pulse
Oh, maybe I am barking up the wrong tree here...
My posts were made on the assumption that you were talking about the floor suspended above the ground (i.e.: soil ).
There is no benefit to thermal insulation between stories in a house as the stairwell alone would undo any benefit, and the difference in temperatures across occupied levels would not warrant any effort in this regard.
Greg
Actualy I think he is talking about both floors. The ground floor for thermal insulation and the first floor for acoustic insulation.Quote:
Originally Posted by gregoryq
Thanks everyone. Bazza is right I started off talking about in between the ground and first floor and also spoke about the ground floor (under the house).
cheers
Cobber