Floor Insulation in straw new build 2 storey barn

[Strawman]

13.5 x 5 m chipboard floor on void with gabion baskets. What floor insulation? I have read a few of the previous messages on this topic but they are not helping much. I thought just go for cheapest as the budget has all but gone but polystyrene is meant to be worthless. Any product ideas welcome please?

Edited July 13, 2020 by Strawman

[Gone West]

2 hours ago, Strawman said:

I thought just go for cheapest as the budget has all but gone but polystyrene is meant to be worthless.

What type of polystyrene and worthless in what way?

[joe90]

Polystyrene is an oil based insulation which is unusual in a straw build!!!!, not worthless but which type as they have different qualities?

[Strawman]

Thanks @PeterStarck and @joe90 do you have any product suggestions? Polystyrene or otherwise?

Many thanks

[Gone West]

Is the insulation to go on top of or underneath the chipboard flooring as that would have a bearing on the type of insulation used.

[Strawman]

Under, thanks 

[joe90]

How was the floor designed, surely insulation was included in that design?, as @PeterStarck says it depends where in the floor buildup it was planned. With such a “green” build method I would have thought a “green” insulation was planned for. You mentioned gabions so there is a void under the floor, rodent proofing will be another consideration.

[Gone West]

3 minutes ago, Strawman said:

Under, thanks

What is the depth of the void and what type of joists do you have. A sketch might be useful.

[Conor]

14 hours ago, joe90 said:

Polystyrene is an oil based insulation which is unusual in a straw build!!!!, not worthless but which type as they have different qualities?

98% air tho. It's certainly not as bad in terms of composition as phenolics.

 

Second your comment tho, would have though an opportunity for something like sheep's wool stuffed between joists? Or blown cellulose?

[Onoff]

A GD build at Lammas use recycled EPS beads as floor insulation I seem to remember. Justified on the basis it would otherwise have gone to landfill. All they had to do was collect. 

 

They also used rammed earth tyre walls, again gotten free. 

[Strawman]

60mm void   joists  47 x 197 C24 floor joists at 400c/c, nogged at mid span

[Strawman]

There is no roof atm so that is a concern re natural products getting wet. Also now time is against us too so loose material v boards becomes trickier and as I said cost. At this stage i just need to get it in. I am trying to be as green as I can but i mindful of other real pressures

[jfb]

WHy 60mm void if the joists are 200mm?

Diagram useful here.

If you only have space for 60mm insulation it is going to be well below building regs.

[Cpd]

50 minutes ago, jfb said:

WHy 60mm void

I expect this is the air gap below the joists..... but I may be wrong. 
 

[joe90]

Drawing please.........

[Gone West]

6 hours ago, Strawman said:

60mm void   joists  47 x 197 C24 floor joists at 400c/c, nogged at mid span

 

6 hours ago, Strawman said:

There is no roof atm so that is a concern re natural products getting wet. Also now time is against us too so loose material v boards becomes trickier and as I said cost. At this stage i just need to get it in. I am trying to be as green as I can but i mindful of other real pressures

Am I correct in thinking the joists sit on a plate on the gabions where the joists are 60mm above ground and that the chipboard floor is fitted. If so I would consider leaving insulating the floor until the house is weatherproof and then possibly blowing in EPS beads if the oversite is suitable.

[Strawman]

thanks Peter. Just seen this. That would have been a good idea worth thinking of but I was under pressure. In the end I have gone for celatex. Thanks again for your time and advise. I really like having this community, just need to make sure I use it earlier in future!