underfloor insulation help!!

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houstonwehaveaproblem

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Part of our integral garage is partitioned off and the floor has been raised with timber joists which are covered with chipboard. There is no insulation underneath in the cavity which is a concrete floor base however there is a Damp proof membrane across the entire concrete floor. Getting the floor up will be quite a task.This cavity is just under this floor. It does not flow through the rest of the house as its the old garage floor which is lower than the house floor thus being raised.

Do I need to insulate this cavity?? Is there an alternative method to insulate other than lifting the floor??
 
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If you're planning to heat that space you should insulate. The best way to insulate that floor is to install a radiant barrier right over the chipboard.
This 1/4" barrier will give you a R-14.5 and it works great under laminate floors and carpet. It's also a moisture barrier. I've used this product in many of my client's homes and my own.

Wishing you success.[/url]
 
Just a note, as you may have missed the part where I said that I have no affiliation to that particular website. But your call.
 
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houstonwehaveaproblem said:
Do I need to insulate this cavity??
Click to expand...

Surely it only needs insulating, if it needs insulating - ie as part of some controlled work?

If its already built and furnished, then why would it need to be insulated?

If you choose to insulate it, then you will have to lift the boards, lay an appropriate insulation to fully fill the void and leave no air gaps, and then relay the floor
 
hmm

Its cold in the room which is coming from under the floor. The cavity beneath which is the old garage floor is about a foot deep. Its a concrete floor under there.

:confused:
 
The cavity beneath might be supplying ventilation to the underfloor in another part of the house, you could still stick a few inches of polystyrene or such in between the joists though. Furniture moved carpet up, unscrew the chipboard, will take a couple of people a couple of hours to do.
If the chipboard is nailed, count your blessings, as you will then have to break it to get it up and have the perfect excuse to replace it with proper floorboards or plywood.

You do have carpet underlay I presume?
 
yes we have underlay fitted. The cavity only serves the room which was previously part of the garage and the underfloor void does not lead anywhere else. What has happened is the floor has been raised by means of wall plates fitted with joists and hangars so it is suspended above the old garage floor. The garage is integral and was only accessed before by way of an up and over door. Since then a doorway has been knocked through from the house and a stud partiton wall has been constructed thus creating a new room but still keeping part of the garage at the front with an up and over door still in place
 
Ok some photos to make it a bit clearer

playroom%203.JPG
 
So as you can see from the photos the floor of the new room is suspended over the original garage floor and this new cavity is just in this garage and does not provide a void to the rest of the house

Question is do I need to insulate under there?? Should underlay and carpet provide good enough barrier to prevent heat loss etc??

Any other ideas as to provide insulation other than lifting the chipboard floor. (this is down solid and the retaining screws are behind the bottom of the plasterboard fixed into the wall plate)

Cheers
 
From your text and pictures, I might guess that the only ventilation
to this floor is from the holes at one end?
Therefore the question you need to ask is, is there a damp proof membrane under the garage floor?
As ventilation will only take place if there is another vent in the oposite wall. It there is no cross flow then your woodwork may rot.
Probably the best move, is pull up the floor, lay a plastic dpm over the garage floor and tight fit polystyrene sheets between all the joists, making sure there are no holes for the heat to escape through.
 
There is a damp proof membrane fitted over the top of the garage floor and up the sides of the walls to the base of the new floor.
 
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