Attic Insulation Question

engrish?

Hey,

I have 100mm insulation between the joists and I am going to add 200mm across the top of the joists. A small section of the attic has plywood on it which is great for storing suitcases etc. I would not like to lose that space.

Is it possible to raise the joists or can I just pu the ply down on top of the insulation? Is raising the joists a difficult job?

Thanks

DublinDilbert

engrish? wrote: »

Hey,

I have 100mm insulation between the joists and I am going to add 200mm across the top of the joists. A small section of the attic has plywood on it which is great for storing suitcases etc. I would not like to lose that space.

Is it possible to raise the joists or can I just pu the ply down on top of the insulation? Is raising the joists a difficult job?

Thanks

If you compress the insulation under the ply you'll loose its effectiveness. If its only a few square meters of ply (like my attic) I would just leave it as it is and do everything else with the extra layer.

If you want extra insulation under the floored area you've 2 options, you can get attic flooring with insulation on the under side, its about 4" tick and is quite pricey. The other option is to lift the flooring you have there already, and run some say 3 x 2's going the opposite way to your existing joists. You can secure the 3x2's with right angle brackets to the existing joists. Then put 100mm of fibre glass in between the 3x2s and pop your flooring back down on top.

engrish?

DublinDilbert wrote: »

If you compress the insulation under the ply you'll loose its effectiveness. If its only a few square meters of ply (like my attic) I would just leave it as it is and do everything else with the extra layer.

If you want extra insulation under the floored area you've 2 options, you can get attic flooring with insulation on the under side, its about 4" tick and is quite pricey. The other option is to lift the flooring you have there already, and run some say 3 x 2's going the opposite way to your existing joists. You can secure the 3x2's with right angle brackets to the existing joists. Then put 100mm of fibre glass in between the 3x2s and pop your flooring back down on top.

Hi,

The floored section is quite small but it's the area all above the landing which is the area of most hestloss. Would it be a bad idea to lay one three by two on top of the other so that I can get an area of 6" to insulate below the flooring?

Thanks

DublinDilbert

If it's a small area just buy the insulated panels. You could use get ticker than 3x2, was just using that as an example. If you want you could just get 4x2 or 6x2, just cut some small pieces up and use them as cross pieces (noggins), to stabelise it. I think there's a tread here showing some pics of it...