how to raise attic floor 8 inches for insulation

batman1

hi. i am planning on topping up insulation in the attic and would like an opinion on raising the floor for storage.

I will be laying 8 inches of insulation across the joints. I want to use half the attic for storage so am looking to floor that half.

What's the easiest method? I am thinking that i need 8 x 2 inch planks, fitted across the existing joists, fit insulation between and then screw down light plywood on top for finished ' floor'.

Can i get 8 inch wide planks easily or is there an easier way of doing this job?

Mightymouse vs Dangermouse

woodies diy sell loft boards 1220mmx320mmx18mm in packs of 3. think there bout a tenner or less!
Just wondering, what insulation you suggest and how much would you lay, thickness wise?

ted1

The loftboards don't allow for insulation. It needs to be uncompressed. You could add some extra beams 8 inches above existing beams.

TPM

If you want to raise the floor level to fit 8" of insulation you can get 9"x2" easily from any building provider.
These dont actually measure much more than 8"
There is a fair amount ow work involved. You will need to notch the timbers anywhere there are wires or pipes crossing your existing timbers.
You will also need to put in bridging to support the new timbers and keep them upright. You need to be careful if you are fixing (nailing/screwing) them to the existing timbers as you can crack the ceiling below.

All this said it would be a good job.

Another option is to use something like this
http://www.knaufinsulation.co.uk/press_releases/knaufs_super_deck_-_loft_deck.aspx
again most building providers should be able to supply them

sullzz

You really need to get someone in to have a look at this , you would be adding a fair bit of weight onto the existing structure , get a chippy to have a look , you might need extra reinforcement

batman1

not worried about overloading. its only a small area and its dormer . i can run the new planks on top of where the wall timbers are upstairs. the area im flooring is only about 4 metres by 3 metres and will only be used for Christmas decorations and other light stuff.

im looking at 2 or possibly 3 lengths running at right angles to the joists and then screw down ply across them.

on the strength issue, would L brackets on every other joist be enough to keep them upright or will i need to put bracing pieces between the new planks anyway?

wayoutwest

Use the 9"x2" as suggested and screw them to existing joists at right angles to existing ones,using 5x60 or 80 screws to avoid damage to ceiling below [ pre-drill to get them nice and tight]. The distance you set them apart depends on the thickness of the sheet material -roughly 3/4"=500mm centres [position them so the edges of boards meet in the centre of joist]. Screw in some noggings[4"x2" should do] between joists at,say,1 metre spacings -this will prevent joists from leaning over if they warp a little bit. Make sure that you can fit the proposed materials through the loft hatch before purchasing!

stimpson

B&Q sell just the thing:

http://m.diy.com/mt/www.diy.com/nav/build/insulation/loft-insulation/loft_storage_stilt/Diall-Loft-Storage-Stilts-12-Pack-11837507?&action=detail&un_jtt_redirect

Worth ringing to see if they have them in stock. My brother had to drive to Newry to get some.

Bruthal

TPM wrote: »

If you want to raise the floor level to fit 8" of insulation you can get 9"x2" easily from any building provider.
These dont actually measure much more than 8"
There is a fair amount ow work involved. You will need to notch the timbers anywhere there are wires or pipes crossing your existing timbers.
You will also need to put in bridging to support the new timbers and keep them upright. You need to be careful if you are fixing (nailing/screwing) them to the existing timbers as you can crack the ceiling below.

All this said it would be a good job.

Another option is to use something like this
http://www.knaufinsulation.co.uk/press_releases/knaufs_super_deck_-_loft_deck.aspx
again most building providers should be able to supply them

When putting the new beams in at right angles to the existing, no notching should be needed for wiring. Just have to make sure not to pinch wires between the existing and new, and move any that would be pinched, out of the way an inch or 2 to one side.

kneemos

Easiest way is to just throw some sheets of styrofoam over it.Might be a bit uneven,but if it's just Christmas decorations what odds.

beldin

Or use insulated loft boards
http://www.electricirelandstore.ie/Product/Xtratherm-Insulated-Loft-Board/1282/602

These have the insulation already applied.

paddy147

beldin wrote: »

Or use insulated loft boards
http://www.electricirelandstore.ie/Product/Xtratherm-Insulated-Loft-Board/1282/602

These have the insulation already applied.

Still overpriced.:rolleyes:

20 euro in a builders providers.

Benster

Batman, I did something like this a few years ago, here's my experience:

http://www.boards.ie/vbulletin/showthread.php?p=54886772

chippengael

stimpson wrote: »

B&Q sell just the thing:

http://m.diy.com/mt/www.diy.com/nav/build/insulation/loft-insulation/loft_storage_stilt/Diall-Loft-Storage-Stilts-12-Pack-11837507?&action=detail&un_jtt_redirect

Worth ringing to see if they have them in stock. My brother had to drive to Newry to get some.

I have been trying to get these for ages from B&Q - finally got 3 boxes from Tallaght but now I need a 4th. Despite the huge demand, and despite advertising them in their last brochure, B&Q in their infinite wisdom, have discontinued this product. Perhaps they are making too much money. Anyway, good luck finding them.