Insulating and Boarding Loft - Am I along the right lines

[chameleon001]

Hi All,

The next job on my house is going to be getting the loft sorted. I've attached some pictures which shows the general state of things now. For the most part there is about 25-30cm of insulation but the section that is boarded (onto the ceiling joists) just has maybe 1-2 inches of very old insulation in it.

So, my plan is to take up the existing boarded area and remove the old insulation below as it looks pretty knackered (think it's fibreglass type stuff), replace this with 100mm Earthwool, then install loft legs, then cross over with 170mm on earthwork before boarding onto the loft legs. Hoping to get a 4x4m area done which should give me the storage space I need for now.

One question I have it the ceiling joists are 3x2 (80mm deep), so wondering would fitting 100mm of earthwool between joists be too thick and compress it too much, or could it just rise above the joists given I'm just sticking 170mm of insulation across it anyway?

Another question is what insulation would be reasonable to use, been looking at Knauf Earthwool?

Thanks for your help,

Dan

 

[foxhole]

It can just rise above joists.

 

[endecotp]

Another question is what insulation would be reasonable to use, been looking at Knauf Earthwool?

All "wool" type insulations have similar thermal properties. Unless you need particular acoustic or moisture properites (and you probably don't) then choose based on price, availability, "eco" credentials, and handling characteristics. Regarding the last point, some materials are much more pleasant to handle (e.g. sheep's wool) than others (glass fibre).

 

[chameleon001]

Thanks for your help, much appreciated.

 

[chameleon001]

Hi all,

Still planning this, having (stupidly) had a few of the house dry lined I now have an additional job of sealing behind the plasterboard from above to reduce the issue of warm air entering my loft. I am going to go around with low expansion foam to try and insulate the gaps then reinstate.

So my plan is to do this, plus re-insulate the inadequate areas and board a 5x5m area of the loft.

As I am using loft legs, the most economical way to use these is to board with 600mm wide chipboard (as oppose to 300mm wide loft boards).

Am I ok to use sheets of 2400 x 600 x 18mm chipboard for the boards? I have checked and they will go through the loft hatch!

Cheers,

Dan

 

[chameleon001]

It begins. Pulling back insulation to foam in around room perimeters where plasterboard is dabbed to wall.

Had to re route the shower cable as was buried under the insulation .

 

[Doggit]

The insulation you had there was rockwool, and could have been reused quite happily. I would have suggested using ordinary expanding foam, but more sparingly. The low expansion stuff is more used as an adhesive, but should be okay. You already routed the shower cable so that there is no insulation around it, so that's good. You can use the larger boards, but you've got to make sure that you use the right number of legs, and that may mean fitting a leg in the middle of a board, where it's not so easy to screw into. As Endecopt has already said, the insulation will settle slightly and be fine, so basically, I'd say you're on the right track.

 

[chameleon001]

Cheers. Yeh I needed to shift the rockwool to get to perimeter of rooms to seal. I’m going to reuse it underneath my raised platform.

Boards are 600mm wide and loft legs are fine at that width so hoping is ok?

Managed to get all the 100mm layed and 2 widths of 170mm, started on the legs but given in for today, tough going on your own!

Thanks for your help!

 

[chameleon001]

(nearly) finished product.

Just need to figure out the around around the hatch (and insulate the hatch).

Certainly better than it was anyway.

 

[Doggit]

Depending on the construction etc of the hatch, you'd normally glue some PIR or polystyrene to it.

 

[chameleon001]

Yeh thinking a sheet of celotex would do the trick