need advice: how to insulate below floor on addition

[n_o_s_p_a__m]

Hello All,

I bought a home that has an addition which is built on concrete pillars, much like a deck would be. The builder put fiberglass insulation between the floor joists, and it just fell out onto the ground (brilliant, eh?).

The room is cold in winter and hot in summer, and I need advice on how to better insulate the floor.

I was planning on putting new fiberglass insulation between the joists, then covering it with foam sheet insulation. I don't know if this will make it any better or worse, but I am at a loss as to what to do here.

Any comments, advice appreciated.

-KJ

[Art]

The foam sheet needs to be covered since it is flamable.

[tm]

Chicken-wire.

[Roy Starrin]

As discussed, chicken wire will work. There also used to be what I was brought up to call "tiger teeth"---springy pointed single wires about the diameter of the bottom of a wire clothes hanger. One just popped them up between joists and they spring loaded themsleves and held the insulation in place. I used them in my current house 20+ years ago and they are still there. You could ask at a hardware store, or call an insulator and ask.

[Clark Griswold]

HD sells two lengths of the wire or you could make them yourself.

[borgunit]

I would replace the insulation, then staple plastic over it and then use treated plywood to cover over that. I would worry about insects and rodents if it is not "sealed" (but I also do not know how it is protected from the outside).

[nicksanspam]

So would foil, for downward heatflow, eg thin double-foil foamboard with no other insulation.

Nick

[n_o_s_p_a__m]

So just nail foamboarn to the (ground-facing) edge of the joists - or to the underside of the floor?

[nicksanspam]

Sure. Warm air rises, so we only need to reduce heat loss by radiation.

Nick

[m Ransley]

Where do you live , what Zone, what are winter temp lows. This will determine what you need to do.

[n_o_s_p_a__m]

Upstate NY. Winter temp lows here hit about -13F